Posted in Bacteriology, General Microbiology, Microbiology, Science/Nature

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A Multimedia Presentation  on  Shigella

Image result for microbiologist cartoon


Chakra Bhandari

Bikram Shrestha

Amrit Science College,

Department Of Microbiology  Tribhuvan University Nepal


Shigella is named after the Japanese microbiologist Kiyoshi Shiga who isolated the first member of the group in 1896 from epidemic dysentery in Japan which was then called Shigella shiga and is now called as S. dysenteriae.

Shigella is an Enterobacteriaceae

  • Gram-negative, Non-motile
  • Facultative anaerobes
  • Nonspore forming
  • Non-capsulated
  • Non-lactose fermenting except S. sonnei.
  • Catalase positive except S. dysenteriae type1 and Oxidase negative.

Deoxycholate citrate agar and xylose lysine deoxycholate agar is useful selective medium (Shigella do not have a black center in this medium as Salmonella).

Cultural characteristics

Temperature range for growth 10-40°C(Optimum temp 37 °C)

In Nutrient Agar (After overnight culture)

  • 2 mm in diameter, circular, convex, smooth and translucent.

In MacConkey  agar

  • Colorless Colony except for S. sonnei (Pink colony)

In Shigella-Salmonella agar

  • Colorless Colony

Viability:  Death point (56°C for 1 hour), 1% phenol for 30 min,

Viable in water for days and in ice for 1-6 months, In feces, it dies within few hour due to acidity produced by growth of coliform.

Biochemical reactions

  • Catalase positive except dysenteriae type 1.
  • Methyl red positive
  • VP negative
  • Urease negative
  • Citrate negative
  • Oxidase negative
  • No production of H2S
  • sonnei is a late lactose fermenter.

Image result for salmonella and shigella XLD

Classification: based on biochemical and antigenic characteristics.

  1. Subgroup A: S. dysenteriae: 15 serotypes:
  2. Subgroup B: S. flexneri: 8 serotypes.
  3. Subgroup C: S. boydii: 19 serotypes
  4. Subgroup D: S. sonnei: only one serotype


Family Enterobacteriaceae

  1. Shigella dysenteriae: most serious form of bacillary dysentery (Shiga toxin)
  2. Shigella flexneri: shigellosis in underdeveloped countries
  3. Shigella sonnei: shigellosis in developed countries
  4. Shigella boydii: Less frequently isolated from dysentery patients.

Virulence factors:

  • Plasmid antigens: Effectors of plasmid transmit from the bacterial cytoplasm to epithelial cell cytoplasm of the colon.
  • Invasiveness: Virulent Shigella penetrate the mucosa and epithelial cells of the colon in an uneven manner. Intracellular multiplication leads to invasion of adjacent cells, inflammation, and cell death. Cell death is probably due to cytotoxic properties of shiga toxin that interfere with protein synthesis. The cellular death and resulting phagocytosis response by the host account for the bloody discharge of mucus and pus and shallow ulcers characteristic of the disease.
  • Other toxins: It has a Shiga toxin which may be neurotoxic, cytotoxic, and enterotoxin. The enterotoxin property is responsible for watery diarrhea. 

Clinical symptoms

Ranges from asymptomatic infection to severe bacillary dysentery

Two-stage disease: watery diarrhea changing to dysentery with frequent small stools with blood and mucus, tenesmus, cramps, fever

Early stage:

  • Watery diarrhea attributed to the enterotoxic activity of Shiga toxin
  • Fever attributed to neurotoxic activity of toxin

Process involves:

  • Ingestion
  • Non-invasive colonization and cell multiplication
  • Production of the enterotoxin by the pathogenic bacteria in the small intestine;

 Second stage:

  • Adherence to tissue invasion of large intestine
  • Typical symptoms of dysentery
  • Cytotoxic activity of Shiga toxin increases severity


  • Source: Man: Case or carrier.
  • Mode of spread: Contaminated  fingers, food, flies, fomites
  • Person to person transmission
  • Infective dose: 10-100 viable bacilli
  • Highest concentration in stool during early/acute infection 103 to 109 viable bacilli per gram of stool

Laboratory diagnosis

Sampling: fresh stool, mucus flakes, and rectal swabs

Selenite F broth(0.4%) is used as enrichment and transport media (for 9-12 hours)

Culture media: Non-Selective Bromocresol purple lactose agar, Low selective MacConkey agar, High selective Deoxycholate citrate agar and SS agar.

Reservoir: Man only

Transmission: Faeco-oral route

Distribution: Developing country: S. flexneri

Developed country; S. sonnei

Treatment and control:

Ciprofloxacin, Fluoroquinolone,  Azithromycin, Pivmecillinam, Ceftriaxone

  • Preventing infected individuals from handling food
  • Thoroughly washing hands after changing and disposing of an infant’s diaper
  • Disinfecting surfaces handled by infected individuals
  • Not allowing infected children to play in community swimming areas
  • If traveling, consuming boiled or filtered water, fruits peeled by self and hot meals
  • Proper storage of food


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Posted in Health/wellness, Many More, Microbiology, Pharmaceutical Microbiology

एन्टिबायोटिक रेसिस्टेन्ससँग लड्न नेपालले के गर्ने ?

-डा. समीरमणी दीक्षित (सबैको जानकारीको लागि स्वास्थ्य खबरबाट साभार)


जनस्वास्थ्यको पाटोबाट हेर्दा, मानिसले खाने एन्टिबायोटिक कसरी खाइरहेका छन् ? त्यसमा कसको पहुँच छ ? राज्यले एन्टिबायोटिक प्रेस्किप्सनमा ध्यान दिएको छ कि छैन ? हामी आफैँ पनि सुसूचित छौँ कि छैनौँ ? भन्ने पक्षबाट हेरिनुपर्छ ।

यसैगरी, जनावरमा मनोमानी ढंगले एन्टिबायोटिकको प्रयोग भइरहेको छ । त्यो एन्टिबायोटिक लिएको जनावरको उत्पादन हामीले खाँदा (मासुजन्य पदार्थ) एन्टिबायोटिक रेसिस्टेन्स ब्याक्टेरिया हामीले लिइरहेका छौँ कि छैनौँ ? मानव शरीरमा सरेको छ कि छैन भनेर हेर्नुपर्छ ।

एन्टिबायोटिक रेसिस्टेन्स नेपालमा मात्रै होइन विश्वव्यापी समस्या बन्दै गइरहेको छ । केही समययता विकसित र विकासोन्मुख मुलुकमा एन्टिबायोटिकको प्रयोग यसरी गरियो कि त्यसैले समस्या निम्त्याउँदै छ । बेलैमा सोचिएन भने, हामीले भोग्ने समस्या भयावह हुन समय लाग्दैन । चिकित्सकहरुले सामान्य भन्दा सामान्य समस्यामा एन्टिबायोटिक सिफारिस गरिदिए भने परिणाम आगामी दिनमा भोग्नुपर्ने हुन्छ ।

बालबालिकाहरुमा पनि एन्टिबायोटिकको प्रयोग ज्यादा गरियो । स–साना रुघाखोकीमा पनि एन्टिबायोटिकको प्रयोग ज्यादा भयो । कुनै थाह नै नभएको रोगमा पनि सोझै एन्टिबायोटिक प्रयोग गरिदिए । रोगको पहिचान हुनुभन्दा पहिले नै एन्टिबायोटिक सिफारिस गर्न थालियो । अल्पविकसित र विकासोन्मुख मुलुकमा यो समस्या बढ्दो छ । किनकि यस्ता मुलुकमा रोगको पहिचान गर्ने प्रणाली निकै कमजोर छ । हामीहरु भ्याक्सिन त्यति धेरै प्रयोग गर्दैनौँ । भ्याक्सिनको प्रयोग ज्यादा हुने मुलुकहरुमा रोग कम लाग्ने भएकाले एन्टिबायोटिकको प्रयोग पनि कम हुन्छ ।

नेपालको सन्दर्भमा हेर्दा खोप अभियान प्रभावकारी बन्न सकेको छैन । खोपको प्रयोग प्रभावकारी हुन नसकेपछि रोगको समस्या बल्झिन्छ । फलतः एन्टिबायोटिकको प्रयोग बढेको छ । यसैगरी, रोगको पहिचानका लागि ‘डाइग्नोसिस’ गर्ने प्रणाली पनि कमजोर छ । कतिपय अवस्थामा जाँचका लागि विदेशमा पठाउनुपर्ने बाध्यता हुन्छ । एक हप्तासम्म लाग्छ । एक साता त्यो बिरामीले के गरेर बस्ने ? अनि डाक्टरले रिपोर्ट आउनुभन्दा अघि नै एक्टिबायोटिक सिफारिस गरिदिन्छ । जे पर्लापर्ला भनेर उसले एन्टिबायोटिक दिइहालेको हुन्छ ।

हामीकहाँ देखिने रोगसँग जोडिएका अधिकांश समस्या ब्याक्टेरियासँग सम्बन्धित छ । एक्टिबायोटिक दिएपछि रोग कम हुन्छ । बिरामी पनि खुसी । डाक्टर पनि खुसी । यस्ता कारणबाट जनताले एन्टिबायोटिक बदाम खाएझैँ खाइरहेका छन् । बजारमा बदाम र एन्टिबायोटिक किन्नुमा कुनै भिन्नता छैन । बदाम र एन्टिबायोटिक दुवैलाई प्रेस्किप्सन चाहिँदैन । फरक यत्ति हो, बदामभन्दा एन्टिबायोटिक महँगो छ ।

अर्कोतर्फ उपभोक्ता पनि उत्तिकै दोषी छन् । डाक्टरले पाँच दिन भनेर एन्टिबायोटिक सिफारिस गरेको हुन्छ । त्यसको निश्चित समयसीमा हुन्छ । तर हामी भने दुई दिन खाएपछि ठिक लागेजस्तो भयो भनेर छाडिदिन्छौँ । जस्तोः डाइरिया हुँदा एन्टिबायोटिक लिइन्छ । दुई दिनमा नै निको हुन्छ अनि एन्टिबायोटिक छाडिन्छ । पूरै मात्रामा लिने त नगन्य नै हुन्छन् ।

पूर्ण अवधिभर एन्टिबायोटिक नखाँदा सबै ब्याक्टेरिया मर्दैनन् । ती पछि झन् बलिया भइदिन्छन् । मानवभन्दा अघि संसारको अस्तित्वमा रहेका ब्याक्टेरियाहरु आफू जोगिन विभिन्न उपाय अपनाउँछन् । शरीरमा बाँकी रहेका १० वटा ब्याक्टेरिया एक महिनामा नै करोडौं भइदिन्छन् । ती शाखा सन्तान ब्याक्टेरियाहरु आफैँले एन्टिबायोटिक नझेले पनि त्यसको प्रतिरोधका लागि तयार भएर बसेका हुन्छन् । किनकि तिनीहरुले ‘जेनेटिक इन्फरमेसन’ पास गरिसकेका हुन्छन् । अर्को पटक हामीलाई फेरि त्यही रोग लाग्यो भने पुरानै एन्टिबायोटिकले निको हुने सम्भावना कम हुन्छ । त्यसपछि डाक्टरले अझै सशक्त एन्टिबायोटिक दिन थाल्छ । यसरी नयाँ एन्टिबायोटिक पचाउँदै ब्याक्टेरिया सशक्त हुँदै जान्छ र एक दिन कुनै एन्टिबायोटिकले पनि नछुने अवस्थामा पुग्छ । यसलाई एन्टिमाइक्रोबियल रेसिस्टेन्ट भनिन्छ ।

टिबी, डिसेन्ट्री, कलेरा लगायतका रोगमा ब्याक्टेरियाले आफूलाई हिजोको तुलनामा निकै सशक्त र जब्बर बनाएका छन् । अस्पतालमा हुने संक्रमणमा पनि यस्तै घटना सुनिन्छ । यसमा चिकित्सकहरु, नीति निर्माता, अस्पताल प्रशासन र हामी सबैको चासो हुनु अनिवार्य छ ।

धुलोको काणमा पनि ब्याक्टेरियाहरु हुन्छन् । हामीले हाच्छिउँ गर्दा र सास फेर्दा शरीरबाट निस्किएका ब्याक्टेरियाहरु वायुमण्डलको धुलोमा मिसिएका हुन सक्छन् । दोस्रोकुरा, सडकमा जथाभावी फालिने मलमुत्रमा रहेका ब्याक्टेरिया पनि विभिन्न कारणले धुलोसँगै टाँसिएर वायुमण्डलमा डुलिरहेका हुन सक्छन् । एन्टिबायोटिक रेसिस्टेन्सका कारण मानिसको शरीरबाट निस्किएका ब्याक्टेरिया यस्तै धुलोको कणमा मिसिएर अरु मानिसमा सरेमा स्थिति भयावह हुन्छ ।

केही वर्षयता काठमाडौँमा बढ्दो धुलोमा फैलिएका ब्याक्टेरियाले विभिन्न रोगको जोखिम बढाएका छन् । दमको बिरामी बढ्नुको कारण पनि धुलो हो ।

न्टिमाइक्रोबियल ब्याक्टेरिया पनि एक अर्कामा सर्ने क्रम बढ्दो छ । एकै ठाँउमा निस्क्रिय रहने ब्याक्टेरियाहरु पनि धुलोको कणका कारण हाम्रो वातावरणमा फैलन अनुकुल भएको छ ।

अचेल कुखुरा व्यवसायीहरुले पनि कुखुरालाई एन्टिबायोटिक खुवाउने चलन छ । त्यसको रेसिस्टेन्स भएका ब्याक्टेरियाहरु कुखुरामा रहेका हुन्छन् । कथंकदाचित त्यो कुखुरा मारेर फालिएमा वा नपाकेको मासु खाएमा एन्टिबायोटिक रेसिस्टेन्स भएको ब्याक्टेरिया मानव शरीरमा सर्ने अवस्था हुन सक्छ ।

एन्टिबायोटिकका सन्दर्भमा अहिले प्रेस्किप्सनको कुरा उठेकै छैन । प्रेस्किप्सनबिना एन्टिबायोटिक दिन नपाउने नियम बन्न जरुरी छ । बल्ल अहिले नियम बन्न लागेको छ । औषधी व्यवस्था विभागले जुन मन लाग्यो, त्यो एन्टिबायोटिकलाई स्वीकृति दिनु भएन । प्रेस्किप्सनबिना एन्टिबायोटिक दिन नपाउने नियम मात्रै कडाइका साथ कार्यान्वयन हुने हो भने धेरै समस्याको समाधान हुने थियो । १६ वर्षदेखि बजारमा नयाँ एन्टिबायोटिक आएकै छैनन् । यो अवधिमा संसारभर नयाँ एन्टिबायोटिकको आविस्कार भएको छैन । फस्ट, सेकेन्ड, थर्ड जेनेरेसन, लास्ट रिसोर्टका नाममा मात्रै एन्टिबायोटिकहरु बजारमा प्रचलित छन् ।

विभागले कति एन्टिबायोटिक केका लागि बेचिरहेका छन् भनेर अनुसन्धान र जाँच गर्नुप¥यो । डाक्टरको प्रेस्किप्सनमा पनि परीक्षण हुन जरुरी छ । कुन डाक्टरले कति एन्टिबायोटिक किन सिफारिस गरेको छ भन्ने नियमन हुन आवश्यक छ । यहाँसम्म कि फर्मास्युटिकल कम्पनीहरुले पनि एन्टिबायोटिक उत्पादन र खपतमा संवेदना अपनाउनुपर्छ । कोटा तोकेर महिनामा यति चलाइदिए कमिसन दिन्छु भन्नु भएन । कमिसनको लोभमा डाक्टरले चलाउनु भएन ।

एएमआरको सवालमा हामीले मानवका साथसाथै पशुपंक्षीलाई पनि एकसाथ हेर्न आवश्यक छ । त्यसलाई ‘वानहेल्थ’का रुपमा हेर्नुपर्छ । स्वास्थ्य मन्त्रालयले यो शब्दलाई सम्बोधन गर्न सकेको छैन तर पशुपंक्षी मन्त्रालयले यसरी हेर्न थालिसकेको छ । विकसित मुलुकमा पनि वानहेल्थको अवधारणा अगाडि राखेर नीति बनाउन थालिसकेका छन् । अब स्वास्थ्य मन्त्रालयले पनि यसरी हेर्न जरुरी छ । अबका रोगहरु र जनस्वास्थ्यमा चुनौती दिने विषयहरु मानिसबाट मानिसमा सर्ने मात्रै होइन, पशुपंक्षीबाट पनि उत्तिकै रुपमा मानवमा सरिरहेका छन् । यसतर्फ सम्बोधन हुन आवश्यक छ ।

(दीक्षित ग्लोबल एन्टिबायोटिक रेसिस्टेन्स पाटर्नसिप कार्यक्रमका निर्देशक हुन्)

यो पनि पढ्नुहोस्

Posted in General Microbiology, Microbiology


Nepal is a least developed and land locked country. Ecologically it is divided into Mountain region, Hilly region, and Terai region. The majority of the population living in remote and village area and these areas are lacking many facilities and there is unplanned urbanization in developed part resulting in the lack of health care facilities, places, and water supply. Most of them have poor economic status and have little or no knowledge about proper sanitation so that infectious can be prevented. About 70% of all health problems are attributed to infectious diseases. Many children are dying from easily preventable and treatable diseases such as diarrhea and/or dysentery, and acute respiratory infections. Of the various infectious diseases, intestinal parasitosis alone constitutes one of the major public health problems in Nepal. Roughly, over 60% of Nepalese are infected with one or more than one species of parasites. In some rural areas, infection rate can be over 90%. Prevalence of intestinal parasites is 52% in children i.e. at least one intestinal parasite infection and 49% infection rate as the whole population and varies with ethnic group and race. It is peck in during rainy summer and post-rainy season. In Nepal, half of diarrhoeal stool samples show some kind of parasites and polyparasitic infection is common. Among the different intestinal parasitic infection, Ascaris lumbricoides, Giardia lamblia, and Trichuris trichiura are predominant. Overall, intestinal helminths infections alone rank fourth in Top Ten disease in Nepal.
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There is seven institution conducting the study in microbiology discipline and producing nearly 400 manpower in this fields. As per as University requirement to get a master degree, every student should conduct a research based dissertation in the respected field. Many students confused what to do in thesis and how to do. Every year repeating the same work and due to some technical problems, the paper rejected by the publisher to publish in a journal paper.

  1. Mr. Rajan Pd. Adhikari   1994       Microbial Quality of fruits of Kathmandu valley and their utilization in wine making and upgrading protein content of fruits peels by using Aspergillus niger, Trichoderma and Penicillium spp.
  2. Bidya  Shrestha                 1994       Study of campylobacter in diarrheal and non-diarrheal Nepalese children and detection of  in diarrheal children
  3. Anjana Maharjan             1994       Bacteriological investigation on ice-cream of Kathmandu
  4. Anjana Shrestha               1994       Study on the water pollution of Ranipokhari and use of fish culture as a biological control of pond pollution
  5. Kedar G.C.          1994       An indigenous fermented food of Eastern Nepal
  6. Shova Shrestha                 1994       Study of physical composition and bacteriological analysis of solid waste of Kathmandu city
  7. Dwij Raj Bhatta                 1994       Isolation and characterization of thermophilic and amylase positive bacteria from hot spring of Nepal
  8. Pradeep Kumar Shah     1994       Biotyping of coagulase-negative staphylococci (CONS)
  9. Peare Banmali   1994       Bacteriological study of food and water of Pode community of Kirtipur
  10. Bimmi Shrestha                1995       Epidemiology and microbiology of lower respiratory tract infection among adult patients in Nepal
  11. Gyanendra Bd. Karki       1995       Bacteriological study of chicken and buff meat of Kathmandu valley
  12. Indu Bikram Joshi             1995       Preliminary survey of dominant bacterial flora of indoor air of Kathmandu
  13. Arjuman Shrestha           1995       Proteolytic Activities of mesophilic Bacteria
  14. Sangita Shakya 1995       Study on the impolite activities of fungi isolated from different oil mill areas
  15. Prakash Ghimire               1995       Prevalence of Bacteriuria and UTI in Nepalese women
  16. Dev Kumar Ranjit             1995       Study of antimicrobial resistant Escherichia coli
  17. Buddhi Pudasaini             1995       Study of solid waste of Kathmandu Valley and its impact on Kathmandu
  18. Motilal Shrestha              1995       Microbiology of wound infection, a hospital-based study
  19. Durga Ghimire   1995       Bacteriological profile of bacteremia patients visiting Patan Hospital
  20. Ira Tuladhar        1996       Bacteriological study of cheese of Kathmandu City
  21. Bishwa Kala Aryal             1996       Serological analysis of Escherichia coli isolated from various clinical specimens with special interest in gastroenteritis
  22. Sabina Dangol    1996       Microbiology of worm infection at Tribhuvan University Teaching Hospital
  23. Rabindra Acharya             1996       A research on integrated fish culture utilizing human wastes in Nepal
  24. Pradipta Udas    1996       Bacteriological study of ice-cream butter and raspberry of Kathmandu city
  25. Pravin Malla “Shrestha”                1996       Improvement of nutritional value of soybean by fermentation  using Aspergillus oryzae
  26. Amod Kumar Pokharel 1996       Micro-Biological Study of paper industries effects
  27. Bihnesh Shrestha             1996       Screening of thermophiles from hot spring of Nepal for thermostable proteases.
  28. Kusumabati Bagracharya              1996       Bacteriological analysis of intestine of fish and its environment
  29. Usha Joshi           1996       Hazard analysis critical control points module of traditional Nepalese meat based street foods
  30. Sagarika Manandhar       1996       Microbiology of urinary tract infection a hospital based study
  31. Sarita Manandhar            1996       Isolation of pectolytic microorganisms from citrus fruits and characterization of the pectic enzymes
  32. Rashmila Prajapati           1996       Fermented soybean: A possible replacer of fish meal
  33. Rina Pradhan     1996       Isolation of Bacillus thuringiensis from soils of Nepal and its insect toxicity.
  34. Paru Joshi            1996       Bacteriological study of fresh vegetables of Kathmandu valley
  35. Bashudha Shrestha         1996       Isolation of salmonella species from blood and study of its antibiotic sensitivity patterns
  36. Pradipta Bhushan Pokhreli Udas               1996       Bacteriological study of ice-cream butter and Rasberry of  Kathmandu city
  37. Chandra Prakash Bhatta                1996       Study of different diagnostic methods and prevalence of Pulmonary tuberculosis among Nepalese population
  38. Deen Bandhu Bhatta      1996       Hazard analysis critical control point process in milk chain
  39. Gyanendra Ghimire        1997       Studies on amylolytic activity during solid state fermentation of morcha a traditional yeast starter of Nepal
  40. Manoj Thapa     1997       Bacteriological study of water and its treatment using plant products
  41. Kishor Manandhar           1997       Serological survey of hepatitis B surface antigen among the healthy Nepalese males
  42. Sarala Joshi         1997       Microbiological study of bodily-fluid
  43. Rakesh Kumar Jha           1997       Fermentable soybean a suitable protein source in fish diet in relation to its enzyme system
  44. Batu Krishna Sharma Kuinkel      1997       Study on air microflora of Kathmandu valley and its seasonal and location variation
  45. Era Shrestha       1997       Study on B-Lactamase activity by microbiological and biochemical methods in Staphylococcus aureus from healthy Nasal carriers and Hospital Isolates
  46. Bikash Pandey   1997       Microbiological and chemical analysis of food beverages (alcoholic and non-alcoholic) of Kathmandu valley
  47. Manju Shree Shakya      1997       Microbial analysis of burn injuries at burn unit of different hospitals
  48. Chandana Gurung           1997       Study of etiology of acute diarrhea with special interest in Salmonella and Shigella
  49. Rajeev Mani Nepal          1997       Nutritional improvement of soybean by fermentation for its possible use in feed for developing state of carp family
  50. Puspa Man Shrestha      1997       Bacteriological analysis of fish and its environment and enzymatic activities of fish isolates
  51. Kalpana K.C.       1997       Isolation of antibiotic-resistant enteric bacteria from community ponds and their antibiotic transfer mechanism in such environment
  52. Sushilman Singh pradhan             1997       Optimization of Nutrient conditions for thermostable protease production
  53. Rishi Prakash Niraula      1997       Hazard Analysis critical control point (HACCP) process of cheese manufacturing in Nepal
  54. Binod Lekhak     1997       Study on industrial effluent and its biological treatment using LEMNA species
  55. Sampurna Singh Dangol                1997       Cauterization and Optimization of amylase produced
  56. Leela Shrestha  1997       Microbiology of Burn Wound in Children at Kanti children’s hospital
  57. Kritika Gautam 1997       Prevalence of urinary tract infection on children
  58. Rumu Amatya   1998       Studies on mesophilic and thermophilic microorganisms commonly found in compost piles of Kathmandu valley
  59. Bishnu Raj Tiwari              1998       An epidemiological study of antibiotic resistant enteric bacteria in a suburban community of Kathmandu valley.
  60. Anjana Shakya 1998       Microbiology of oral cavity with special interest to B-Hemolytic Streptococcus
  61. Kiran Shah           1998       Characterization of E-coli isolated from urinary tract infected patients
  62. Keshab Parajuli                 1997       Study of causative organisms from pus sample and its antibiotic sensitivity pattern
  63. Luna Bhatta        1998       Study of antimicrobial properties of Punica granatminum
  64. Makhan Maharjan           1998       Assessment of groundwater quality and study of antibiotic resistance and oligodynamic action against some isolated enteric bacteria
  65. Reshma Tamrakar            1998       Antibacterial activities of antinomy cetes isolated from soils of Kathmandu valley
  66. Sunil Manandhar              1998       Impact of effluents on rivers and reduction of biochemical oxygen demand using Cladosporium oxysporum
  67. Archana Shrestha            1998       Cervicitis and cancer of in Nepal
  68. Kaushal Joshi     1999       A prospective study on the bacteriology of lower respiratory tract infection among the patients visiting T.U. teaching hospital Kathmandu
  69. Jyoti Amatya      1998       Study of urinary tract infection and cancer of urinary bladder
  70. Krishna Lal Kandel            1999       Infection of foot ulcers in Leprosy Patients
  71. Archana Katuwal              1999       A perspective study on bacteriology of would infection among impatient at Bir Hospital (A Hospital Based Study)
  72. AnJali Tibrewal 1999       A perspective study on etiological agents causing infective endocarditis and related bacteri\aemic and septicemic cases among patients visiting Bir Hospital
  73. Hirdaya Ratna Shakya     1999       Prospective study on etiology of childhood diarrhea based on clinical features and laboratory investigation
  74. Monika Joshi      1999       Seroprevalence of hepatitis B And hepatitis C infection among blood donors in Kathmandu valley
  75. Puspa Raj Dahal                1999       Utilization of fruit wastes for the production of citric acid via fermentation by using Aspergillums
  76. Buddhi Sagar Ghimire    1999       Utilization of tea wastes as a substrate for microbial protein production
  77. Rupa Acharya    1999       Production of aflatoxin by Aspergillus flavus isolated from different edible foodstuffs of Kathmandu
  78. Deepak Singh    1999       Antibacterial activity of actinomycetes isolated from the various geographical region of Nepal and characterization of their antibacterial agents.
  79. Bijaya Kumar Dhakal       1999       A prospective study of urinary tract infection based on culture and direct microscopy of urine along with the antibiotic sensitivity test of urinary pathogens
  80. Krishna Prashad Subedi                 1999       Insecticidal activities and immunology of delta-endotoxins of Bacillus thuringiensis isolated from insect samples of Nepal
  81. Roshana Joshi (Shrestha)             1999       Preliminary test of bacteriocins from Pseudomonas sps isolated from potato
  82. Sandesh Regmi                 1999       Isolation, screening, identification and selection of best fermentative yeast from m0rcha sample
  83. Aarati  Karki        1997       Prevalence of acute diarrhoeal episodes in Kathmandu valley during 1997
  84. Pallavi Sthapit    1999       The Isolation and identification of antibiotic producing bacteria in the compost samples of Kathmandu valley
  85. Shaila Basnyat   1999       Studies on effect of pesticides on soil inhabiting bacteria of pesticide applied cultivated fields of Kathmandu valley
  86. Palpasa Tuladhar              1999       A perspective study on bacteriology of wound infection at Tribhuvan University Teaching Hospital
  87. Reena Lamichhane          1999       Study of Methicillin-resistant Staphylococcus aureus  (MRSA) isolated from different clinical samples
  88. Chenu Gongol   1999       Fermentation of grape juice by using brewing yeast isolated from Nepalese starter-murcha
  89. Leena Rajbhandari          1999       Efficiency of alcohol fermentation of Herdemu  vulgate (Naked barley) from traditional murcha
  90. Sanchita Sapkota              1999       Antibacterial Activity of natural honey: A preliminary study
  91. Thakur Prasad Paudel    1999       Drug-resistant enteric bacteria in poultry samples of Kathmandu valley and their epidemiological study by plasmid profiling
  92. Harish Chandra Shrestha              2000       Screening of aflatoxin-producing Aspergillus flavus isolated from maize and study on their growth suppression by various chemical agents
  93. Nawa Raj Banjade          1999       A prospective study on etiology of bacteremia septicemia at Tribhuvan University Teaching Hospital
  94. Anand Bahadur Chand   2000       A prospective study on Aetiological agents of diarrheal disease in children in relation to parasites and to determine the antibiotic sensitivity pattern of isolates
  95. Binita Panta        2000       A study on sexually transmitted infections among the patients visiting at Tribhuvan University Teaching Hospital
  96. Sujan Piya           2000       A study on diarrhea in children in relation to behavioral and environment factors
  97. Dev Raj Joshi      2000       Studies on the role of exopolysaccharide of Xanthomonas campestris V. campestris, isolated from cabbage seeds, in pathogenesis and correlation of exopolysaccharide in pathogenicity on host plants
  98. Abhignya Subedi              2000       Prevalence of multiple drug resistant enteric bacterial pathogens in diarrhoeal patients of Kathmandu and study of their relations by plasmid profiling
  99. Priyambada Paudyal       2000       Study on the relationship between the infections of Helicobacter pylori and Epstein-Barr virus and the carcinogenesis of the gastric cancer
  100. Chandra Kala Rai               2000       A perspective study on antibiotic sensitivity profiles of the organisms associated with clinical infections among the patients attending T.U. Teaching Hospital; A hospital based study
  101. Arishma Rajkarnikar (singh)         2000       Antibiotic resistant Vibrio cholerae isolated from Kathmandu valley and characterization of the isolates by biotyping and serotyping
  102. Shiva Raj Pokhrel             2000       Microbiological and chemical analysis of mineral water sold in the Kathmandu valley
  103. Naba Raj Pokhrel             2000       Screening and evaluation of the antimicrobial activity of some medicinal plants of Nepal and isolation of pure antimicrobial compound four bushfire variegate
  104. Pankaj Acharya 2000       Microbiological study on street fried foods and isolation and identification of some microorganisms of public health importance
  105. Purushotam Prasai          2000       Microbiological study of raw meat of Kathmandu valley with public health and veterinary importance and serological study of the isolated Salmonella species
  106. Sunita Pokhrel   2000       Serodiagnosis of Syphilis among clinically suspected patients visiting Bir Hospital and the Risk of HIV and Hepatitis B infection among syphilitic patients
  107. Munman K.C.    ——-    Bacterial analysis of street food in relation to child health
  108. Bhupesh Khadka              2000       Immunodiagnostics for tuberculosis
  109. Sapana Sharma                 2000       Antimicrobial activity of essential oils of some common species
  110. Rajandra Prasad Aryal    2000       Study on viruses in relation to skin cancer among Nepalese people
  111. Parmeshwor Narayan Amatya   2000       Study on cytokine (interferon-gamma) responses to skin test antigens of leprosy
  112. Chariu Arjyal      2001       Bacteriology of ear discharges
  113. Pratap Karki        2001       Study of solar Disinfection of drinking water
  114. Prakriti Raj Kandel           2001       A study of severe Malaria in relation to HIV and syphilis among patients visiting Bheri zonal Hospital
  115. Abhilasla Karkey               2001       Monitoring of liver and renal function among human immunodeficiencyvirus-positivee individuals
  116. Rupa Shakya      2001       Study on bacterial flora in blood specimen collected from hospitalized and outpatients service of T.U. teaching hospital
  117. Prerana Bajracharya       2001       Sero-diagnosis of Japnese Encephalitis and malaria and an assessment of public health awareness about the above diseases (A study confined within BHERI Zonal hospital)
  118. Prakash Kumar Paudyal 2001       Study of physicochemical and bacteriological parameters of Bagmati river and treatment of polluted water using Cladosporium resinoe
  119. Suresh Subedi   2001       Study of the prevalence of helicobacter pylori in gastroduodenal diseases and evaluation of antibiotic sensitivity pattern of the isolates.
  120. Ganga Gharty Chetri       2001       Prevalence of tuberculosis among the suspected patients visiting Tribhuvan University Teaching Hospital and their antimicrobial resistance pattern
  121. Arjun Thapa       2001       Study of indoor Vs. outdoor air microfilaria and its relations to PM 7.07
  122. Giri Raj Dahal     2001       Air quality assessment of Brick rain area
  123. Shila Bhattarai   2001       Study of microflora of vermicompost and its antagonistic activity against plant pathogenic bacteria
  124. Saphala Dhital    2001       Determination of antibiotic resistant gram negative urinary pathogens in pediatric patient at Kanti children’s hospital
  125. Rama Dhungel   2001       Prevalence of common bacterial different clinical samples pathogens in submitted at Tribhuvan university teaching hospital and their antibiotics sensitivity test profiles
  126. Mahesh Ram Baidya       2001       Screening and evaluation of in vitro antimicrobial activity of medicinal plants of Nepal
  127. Buddhi Kumar Shrestha                2001       Study of hazard dialysis critical control point (HACCP) system in sausage production plants
  128. Anju Sharma      2001       Enumeration and isolation of pesticide-degrading bacteria from different soil samples of Kathmandu valley and study on transferability of degradative plasmid from Pseudomonas Putida isolates into E. Coli
  129. Lata Ghimire      2001       Study of microbial flora present in the conjunctiva of the cataract patients before and after the use of betadine solution and its antibiotic sensitivity pattern
  130. Sushama Sharma             2002       Study of Microbiological  and chemical quality of fermented milk (DAHI) of Kathmandu valley
  131. Chaman Ranjit   2001       Distribution of citrus Tristeza virus in various regions in Nepal and development of virus-free plantlets by meristem culture
  132. Tarani Prasad Paneru     2002       Antibiotic sensitivity profile of Escherichia coli, Klebsiella and Pseudomonas of patients visiting TUTH Kathmandu
  133. Megha Raj Banjara          2002       Study of air, water, and wound infection in different words of T.U. Teaching Hospital
  134. Sangita Bhattarai              2002       Insecticidal activities of Bacillus thuringiensis against Culex quinquefaus and Spodopter litura
  135. Kiran Babu Tiwari             2002       Study of Meningitis in patients University teaching Hospital
  136. Nawaraj Dhakal                2002       Microbial Digestion of vegetable and Kitchen wastes for Biogas
  137. Yogan Khatri       2002       Development of IND-elisa for for actinomycetes and Study of Senological Relationship
  138. Supriti Shrestha                2002       Assessment of Drinking water quality supplied by Nepal supply corporation Sundarighat and identification, Antibiotic sensitivity pattern and serotyping of isolated Escherichia coli.
  139. Sriju Sharma       2002       Pattern of Microbial flora among the visitors and the environment of intensive care unit (ICU) Tribhuvan University teaching Hospital
  140. Rajita Rajbhandari           2002       Prevalence and Antibiotic Sensitivity Pattern of Methicillin Resistant Staphylococcus Aereus (MRSA) in Bir Hospital
  141. Aashish Poudyal               2002       Salmonella Serotyping and Drug Susceptibility pattern from Environment and Clinical Samples of Urban Nepal
  142. Anima Shrestha                2002       Bacteriological Study of Upper Respiratory tract infection in pediatric patients
  143. Rupa Pandey     2002       A. Hospital based study of urinary tract infection among women visiting antental clinic of tribhuvan universit teaching hospital
  144. Tista Prasai          2002       Drinking water quality assessment of kathmandu valley and antibacterial property of Enteric Bacteria Isolated
  145. Deepak Acharya               2002       Prevalence of beta-haemolytic sterptococci in throat of school children and its antibiotic sensitivity pattern.
  146. Khadga Bikram Shah       2002       Study on nasal carriage of Staphylococcus aureus among the post operative ward visitors, staff and patients of TU teaching hospital with drug sensitivity pattern
  147. Bishwa Raj Thapa             2003       Optimization and use of polymeisase chain reaction for the diagnosis of tuberculosis and Leprosy
  148. Durga Shreatha                 2003       Prevalence of Bacterial infection in Acute hepatitis in Nepal
  149. Sneha  Bam        2002       Quality control in tuberculosis smear microscopy
  150. Ita Bhattarai       2003       Study of the prevalence of camfryholacter in Daw meat and drinking water in water corporation of Kathmandu and Possible research for shigella
  151. Janak Raj Dhungana        2002       Tuberculosis and human immuno deficiency virus co-infection in united mession hospital Nepal
  152. Binod Prasad Pathak       2003       A prospective study on acute group a streptococcal pharyogitis and its delayed sequelae on school children of Kathmandu valley, Nepal
  153. Diyo Ram Rai      2003       Study of the factors associated with enteric parasitic infection among school children in a rural village setting in Kathmandu valley, Nepal
  154. Narayan Raj Bhattarai    2003       Anti-tuberculosis treatment resistant in pulmonary tuberculosis patients visiting German-Nepal tuberculosis project kalimati, Kathmandu,
  155. Keshav Rai          2003       Relative study of enterophathogens (parasites and bacteria) in gastroenteritis and its predisposing factors
  156. Rajender Prasad Subedi                2003       Study of Ambient air micro flora of Kathmandu valley and its relation to P.M. 10
  157. Darshan Sapkota              2003       Prevalence of anteric parasitosis in HIV/AIDS Patients of Nepal
  158. Nagenra Prasad Yadav   2003       Prevalence of lymptatic filariasis is Dhenusha district of Nepal
  159. Madhu Sudan Pandey   2003       Study on the prevalence of multiple drug resistant Salmonella in poultry birds
  160. Pallavi Gurung   2003       Microbial contamination of the contact lens and its care
  161. Sushil Chandra Regmi     2003       Evaluation of Nitrate test in detecting urinary Tract infection
  162. Salina Gairte       2003       Microbial colonization of maternal genital tract and its relationship to onset of early neonatal sepsis
  163. Bhagabati Panday            2004       Studies on the antibacterial activity of antiromycetes isolated from khambu region of Nepal.
  164. Sachindra Raj Joshi          2003       Carriage pattern of Staphylococcus aureus in healthy school children
  165. Preeti Gautan    2004       Prevalence of Urinary tract infection in Datetic Patients
  166. Pratap Shahi       2002       Comparative Study of tuberculosis test Ziehl Neelsen staining and culture in the diagnosis of tuberculosis
  167. Niraja Thapa       2002       Superficial fungal infection and awareness status among the patients visiting dermatology outpatients department of tribhuvan university teaching hospital
  168. Suraj Dhungel    2004       Moduflation of whole blood immune to phenolic glycolipid (PGTD of M. Leprae)
  169. Smritee Pokharel             2004       Comparative evaluation of different staining techniques for the diagnosis of tuberculosis lymphadenitis
  170. Manoj Ghimire 2004       Evaluation of antimicrobial resistance status in Kirtipur community bacterial isolates
  171. Pukar Acharya   2004       Air quality assessment of Kathmandu Valley
  172. Dipak Adhikari   2004       Production and  characterijation of the antimicrobial substances from Bacillus species
  173. Bharat Khatiwada            2004       Characterization of proteases from Bacillus species producing antimicrobial substances
  174. Punita Gauchan                2004       Lower respiratory tract infection a socio-medical aspect
  175. Chandra Sdhekheir Rajaure         2003       Study on performance of waste water  treatment plant at guheshwari
  176. Jaya Sharma       2004       A prospective study on microbiology of lower respiratory tract infection and antibiotic sensitivity profile with interest in multidrug resistance and extended spectrum of betalactamase strains
  177. Surath Uuadhyaya           2004       Prevalence of Lymphatic filariasis in Parsa District of Nepal
  178. Puspa Raj Pandey            2004       Field evaluation of the OPTimal test for the rapid diagnosis of malaria
  179. Deepak Joshi     2004       An epidemiological study of malaria in Kanchanur District during 2003
  180. Yadav Wagley    2004       Microbiology of Bacteraemia and septicemia in patients visiting Tribhuvan University, Teaching Hospital (TUTH) Kathmandu.
  181. Anjita Rajbanshi               2004       Study on heavy metal resistant bacteria in the waste water treatment plant at Guheshwori
  182. Abhilasha Gurung            2004       Prevalence of catheter associated urinary tract infection as Hospital acquired infection in TUTH
  183. Amin Khadka     2004       Comparative evaluation of four different tests in the diagnosis of Visceral leishmaniasis in Nepal
  184. Toya Nath Sapkota          2004       Microbial quality evaluation of milk and butter with special reference to the milk pathogens and MBRT test
  185. Komal Rajj Rijal 2004       An epidemiological study of anti-tuberculosis drug resistance pattern in the pulmonary tuberculosis patients visiting national tuberculosis centre.
  186. Munal Subedi    2004       A Hospital study of urinary tract infection among pregnant women visiting Lumbini Zonal Hospital, Butwal
  187. Amrit M.S. Maharjan      2002       Study on the impairment of liver kindney and pancreas in Hepatitis B and C positive cases
  188. Ranjan K. C         2004       Enteropathogens associated with acute diarrhoea in patients visiting National Public Laboratory, Teku.
  189. Bijaya Malla        2004       Study on nasopharyngeal pneumococcal carriage enteroparasitic infectations in children
  190. Sabina Shrestha                2004       Study on the prevalence of Salmonella species from blood sample of the patients visiting national public health  laboratory, Teku
  191. Santosh Thapa  2004       Prevalence of Methicillin resistant Staphylococcus aureus (MRSA) in children visiting Kanti children’s Hospitals
  192. Narayan Prasad Kandel 2004       Bacteriological profile of bacteraemia and speticaemia among patients of infective endocarditis
  193. Deepu Pudasaini              2004       Microbial study of chronic obstructive pulmonary disease in patients admitted in Nepal Medical College Teaching Hospital, Jorpati
  194. Puja Shrestha    2004       A prospective study of urinary tract infections in female patients attending Kathmandu Model Hospital
  195. Nirajan Thapa Kshetry   2004       Prevalence of Aeromonas in different clinical samples and water with special interest in Gastroenteritis
  196. Raj Kumar Karki                2004       Serostatus of rheumatoid factor, c-reactive protein, antistreptolysin-o and uric acid in patients visiting OM Hospital and research centre
  197. Gokarna Raj Ghimire                      Study of urinary tract infection among kidney transplant patients visiting National Public Health Laboratory, Teku.
  198. Bijaya Bajracharya           2004       Prevalence of vulvovaginal giardiasis in females attending gynecological outpatient department of Tribhuvan University Teaching Hospital
  199. Pradeep Kafle   2004       Seroprevalence of torch in Nepalese women of childbearing age and evaluation of biochemical parameters
  200. Roshani Maharjan           2005       Detection of enteric pathogens (Vibrio Cholerae and Escherichia coli 0157) in childhood diarrhoeal cases
  201. Sulochana Basnet (Mahat)           2004       Prevalence of Urinary tract infection and candiasis of   pregnant women at community based reproductive health care & counseling center of Kirtipur Municipality
  202. Diksha Khadka   2005       Detection of Enteropathogens (Salmonella spp, Shigella spp and Parasites) in the stool specimen of children suffering from diarrhea and admitted at kanti children Hospital
  203. D Radha               2004       Evaluation of antimicrobial activities of some medical plants
  204. Dinesh Thapa     2004       Seroprev valence of hepatitis B and HIV among volunteer blood donors of Kathmandu
  205. Dipendra Gautam            2005       Prevalence of lower respiratory tract pathogens (bacterial) in Nepalese HIV/AIDS Patients
  206. Prakash Chandra Amatya             2004       Study of Bacteraemia in malnourished children admitted to Kanti children’s hospital
  207. Dal Bahadur Khatri           2005       Recovery of sliver from used X-Ray films using alkaline protease extracted from Bacillus spp
  208. Niraj Nakarmi    2005       Screening of soil bacillus species for ß lactamase activity
  209. Susan Pandey    2005       Genetic variability of Mycobacterium leprae in Nepal
  210. Rajdeep Bomjan              2005       Prevalence of multidrug resistant strains with reference to extended spectrum beta-lactamase producing strains among the bacterial pathogens isolated from different clinical samples at Tribhuvan University Teaching Hospital
  211. Trishna Manandhar         2005       Antibiotic susceptibility profile of bacterial pathogens in urinary trace infection with special reference to extended spectrum beta lactamase (ESBL) oridycubt straubs
  212. Deepa Shrestha                2005       Study on Microbiology of urinary tract infection and the prevalence of multidrug resistant strains among the bacterial pathogens
  213. Govinda Prasad Dhungana           2005       Tuberculosis and HIV co-infection in HIV-AIDS persons of Nepal
  214. Uma Shrestha   2005       Cross-sectional study of respiratory pathogenes and their antibiotic susceptibiligy pattern in Tribhuvan Unversity Teaching Hospital
  215. Ajaya Poudel     2006       Loop-mediated isothermal amplification for direct detection of mycobacterium tuberculosis in sputum samples
  216. Niroj Man Amatya           2006       A study on etiological agents of bacteraemia and antibiotic susceptibiligy pattern of isolates
  217. Anjana Upadhayay          2005       Biodiversity and bioactivity of endophytic fungi of tsuga dumosa D. Don
  218. Yukti Basnet       2006       Vermicomposting, enrichment of vermicompost by azotobacter chroococcum and response on phaseolus bean
  219. Bishnu Bhakta Dhungyel               2006       Prevalence of malaria and hepatitis B among Nepalese blood donors
  220. Deepika Shrestha            2006       Evaluation of different staining techniques (Ziehl neelsen stain, Kinyoun stain, Modified cold stain and fluorochrome stain) for the diagnosis of pulmonary tuberculosis
  221. Upendra Thapa Shrestha              2006       Study of delta encotoxin immunocrossreactivity of bacillus thuringiensis isolates from khumbu base camp of the Everest Region
  222. Gyan Sundar Sahukhal   2006       Study of genetic polymorphism among bacillus thuringensis isolates from Khumbu Base Camp of Everest Region by randomly amplified polymorphic DNA polymerase Chain Reaction
  223. Samira Khatiwada            2006       Study of prevalence of enteric fever and the assessment of widal test in the diagnosis of typhoid fever
  224. Sirjana Devi Shrestha     2006       A prospective study on etiology of diarrhea with reference to multiple drug resistant enteric bacterial pathogens
  225. Mr. Sunil Maharjan         2006       Prevalence of intestinal parasitosis among HIV/HIDS patients of Kathmandu Valley and Dhulikhel
  226. Ms. Chamala Lama          2006       Microbiological study among diarrhoeal children in relation to cyclospora and rotavirus infection
  227. Mr. Navaraj Raj Adhikari               2006       Study of prevalence of intestinal parasitic infection among HIV seropositive subjects and high risk group for HIV infection in Bagmati Zone, Nepal
  228. Mr. Dhan Kumar Pant    2006       Assessment of therapeutic of anti-mallarial drug (chloroquine) for plasmodium vivax in kanchanpur district, Nepal
  229. Mr. Bikash Shakya           2006       Study on intestinal infections by parasite and some bacteria among elderly people of Kathmandu Valley.
  230. Jyoti Pant            2006       Microbial study of hospital environment and carrier pattern study among staff in Nepal Medical College Teaching Hosptial
  231. Poonam Thapa  2006       Assessment of hazard analysis critical control point (HACCP) from restaurants of Kathmandu metropolitan city with respect to environmental condition
  232. Shyam Prasad Dumre     2006       Sero-epidemiology of Japanese encephalitis in Nepal
  233. Arina Shrestha  2006       A study on soil transmitted helminthiasis in Kathmandu Valley
  234. Nisha Puri            2006       Study on the incidence of urinary tract infection in diabetic patients and the prevalence of multidrug resistant strains among the bacterial pathogenic isolates
  235. Sanchita Dahal   2006       Prevalence of bacterial and fungal agents causing lower respiratory tract infections in patients with human immunodeficiency virus (HIV) infection
  236. Sudeep Singh    2006       Isolation and identifcaton of the etiolotical agent of pulmonary tuberculosis in patients visiting national tuberculosis center, Thimi, Bhaktapur
  237. Shishir Sharma  2006       Microbial flora among vstors and the hospital environment in ICU and SICU at TUTH
  238. Sangeeta Shrestha          2006       A study on possible contribution of horizontal transmission in neonatal sepsis at TUTH
  239. Kiran Sapkota    2006       Prevalence of methicillin resistant staphylococcus aureus (MRSA) in clinical specimnets from patients and screening of nasal carriage of MRSA from Medical Staffs of Bir Hospital
  240. Dinesh Dhakal   2006       Study of the disease citrus canker and field trial to find its effective control measure in “Kavre” Nepal.
  241. Jeny Shrestha    2006       Effect of dual inoculation of Rhizobium leguminosarum biovar p[haseoli and Piriformospora indica verma et al. on phaseolus vulgaris grown in the soil treated with vermicompost
  242. Rajani Shrestha 2006       Study on the effect of co-inoculation of bradyrhizobium japonicum and pirifirmospora indica verma et al. on glycine max (L.) merr.
  243. Shova Khanal     2006       A study on microbiology of urinary tract nfection at Tribhuvan University Teaching Hospital Kathmandu Nepal
  244. Olivia Thapa        2006       Evaluation of antibiacterial activity of some medicinal plants frequently used in respiratory and gastrointestinal diseases in Nepal
  245. Rachana Manandhar      2006       Pattern of bacterial flora in various out patient departments of TUTH
  246. Asta Ram Khagi 2006       A comparative study of different diagnostic methods for Mycobacterium tuberculosis in suspected patients visiting National Tuberculosis Centre, Thimi, Bhaktapur, Nepal
  247. Sarita Shrestha  2007       Study on prevalence of common types of vaginitis (candidiasis, traichomoniasis and bacterial vaginosis) among the pregnant women visiting thapathali maternity hospital Kathmandu
  248. Nirmala Dhungana           2007       Role of Glomus Microcarpum in the production of whear (triticum aestivum)  plants
  249. Padma Shrestha               2007       Study of bacteria causing urinary tract infection and their antimicrobial resistance trend at national public health laboratory
  250. Rup Bahadur Kunwor     2007       Nalidxic acid resistant salmonella with decreased ciprofloxacin susceptibility
  251. Shiva Ram Pant 2007       Corelation of secondary infection with peripheral level T lymphocyte with CD4 marker (CD$) count in HIV/AIDS patients
  252. Rama Gyewali   2007       A study on Microbiological and chemical quality of water of Kathmandu
  253. Sujata Lamichhane          2007       Study on seroprevalence of IgM Antibiodies against the agents of torch infections among the patients visiting National Public Health Laboratory
  254. Kamil Prajapati  2007       Effect of dual inoculation of azotobacterchroococcum and piriformospora indica verma et al on oryza satwal croun in the soil treated with vermicompost
  255. Shradha Chiplalu              2007       Microbiological study on gastroenteritis of children from Kanti Children’s Hospital with reference to cyclospora and rotavirus infection
  256. Rojita Tuladhar  2007       Comparative evaluation of microscopic and cultural examination in bacterial meningitis among the patients attending Kanti Children Hospital
  257. Anup Muni Bajracharya 2007       Study of drinking quality of Kathmandu Metropolitan areas and evaluation of antibacterial property of some medicinal plants against isolated enteric bacteria
  258. Saraswoti Khadge            2007       DNA fingerprinting of Mycobacterium tuberculosis isolates in Nepal using PCR-labelled is 6110 probe
  259. Bal Ram Adhikari              2007       Use of Loop-mediated isothermal amplification (Lamp) for direct detection of Mycobacterium in sputum
  260. Semuhang Subba             2007       Study of antibiotic susceptibility pattern of mycobacterium tuberculosis in pulmonary tuberculosis patients visiting national tuberculosis center, Thimim Bhaktapur, Nepal
  261. Rojita Tuladhar  2007       Comparative evaluation of microscopic and cultural examination in bacterial  meningitis among the patients attending Kanti Children Hospital
  262. Shradha Chipalu               2007       Microbiological study on gastroenteritis of children from Kanti Children’s Hospital with reference to cyclospora and rotavirus infection
  263. Bina Laxmi Jayana            2007       Assessment of drinking water quality of madhyapur-Thimi ans study of anti bacterial effect of lime juice against bacterial isolates
  264. Kamala Lamsal   2005       Study the hospital environment of shahid gangalal national heart centre
  265. Yasoda Gyawali 2007       Study on bacteriological profile of infected wound from patient’s visiting to lumbini zonal hospital, butwal, Nepal
  266. Deena Shrestha                2007       Prevalence of bacteraemia and septicaemia among children attending kanti children hospital with special reference to salmonella spp.
  267. Pragya Sharma  2007       Study on intestinal parasitic infections in tharu community of bardiya district
  268. Sujaya Nepali     2007       Screening of mycobacterium tuberculoss by selective inhibition with para-nitrobenzoic acid, its cytochemical staining and drug susceptibility to primary anti-tubercular drugs
  269. Bhim Shrees       2005       Microbiological and physico-chemical analysis of alcoholic beverages of Kathmandu Valley
  270. Prashqnna Raj Kafle        2007       Study on drinking water quality of Kathmandu and attending susceptibiligy of isolates
  271. Khagendra Prakash K. C.               2007       Seroprevalence of rubella in Nepal
  272. Madan Singh Bohara      2007       Reproductive tract infections among women attending gynaecological outpatient department Tribhuvan University Teaching Hospital
  273. Sunita Maharjan               2007       Tuberculosis and human imuno-deficency virus co-infection in suspected TB patients
  274. Srijana Thapaliya              2007       Study of biodiversity and bioactivity of endophytic fungi of some Himalayan conifers of Nepal
  275. Prashamsa Karkee           2008       Bacterial isolatres and their antibiogram from wounds and abscesses of surgical outpatients visiting bir hospital
  276. Sushma Acharya               2008       Comparison of the resistance ratio and proportikon methods for drug susceptibility testing of Mycobacterium tuberculosis isolated from patients visiting national tuberculosis centre
  277. Kiran Kumari      2008       Pattern of bacterial isolates and antibiogram from open wound infection an\mong the indoor patients of Bir Hoapital
  278. Binita Koirala      2008       Comparative study of polymerase chain reaction (PCR) and loop-mediated isothermal amplification (Lamp) for direct detection of Mycobacterium tuberculosis in sputum
  279. Khagendra Koirala           2008       Sterid biosynthesis and embryonic stem cell proteins as putative predictive breast cancer biomarker
  280. Sarmila Tandukar             2008       Enteropathogenic microorganisms in children under ten years of age attending Kanti Children’s Hospital
  281. Surendra Karki  2008       Seroprevalence of hepatitisc and HIV among blood donors in Kathmandu valley
  282. Anil Shrestha     2008       Prevalence of soil transmitted parasites in raw vebetables of Kathmandu and stool samples of school children
  283. Rumika Maharjan            2008       Estimation of incidence of HIV infection in Nepal by mode of transmissionamong various exposure groups
  284. Nirajan Bhattarai              2008       Genetic simalasrities among bacillus thuringiensis strains from different climatic zones of Nepal
  285. Chringma Sherpa             2008       Biochemical and molecular characterization of actinomycetes prosessing antibacterial properties from soil samples of kalapatthar, mounteverest region
  286. Tara Devi Gurung             2008       Screening of actinomycetes from soil samples of Kalapatthar mount everest region for antibiosis
  287. Suman Thapa     2008       Immunological screening of actinomycetes of khumbu region of Nepal
  288. Pankaj Baral       2008       Multidrug resistance among various clinical bacterial isolates and production of different types of B-lactamases with subsequent transfer mechanism by plasmid DNA analysis
  289. Sanjiv Neupane                2008       Isolation identification and plasmid profiling of multidrug resistant bacterial pathogens isolated from UTI patients
  290. Suman Lama      2008       An evaluation of 5% NaOCI microscopy method for the laboratory diagnosis of pulmonary tuberculosis
  291. Shree Krishna Shrestha 2008       Assessment of arsenic tolerant bacteria from arsenic contaminated groundwater in nawalparasi district of Nepal
  292. Prerana Dhungana          2008       Isolation and characterization of arsenic tolerant microorganisms from tube well water of Nawalparasi, Nepal
  293. Manita Guragain              2008       Biochemical and genetic characterization of actinomycetes from  mount everest base camp
  294. Narendra Maden             2008       Perspectives of arsenic exposure and asymptomatic microbial infections in Nawalparasi District
  295. Kashi Ram Ghimire          2008       Microbiological quality evaluation of dahi/yoghurt of Kathmandu Valley
  296. Bishnu Prasad Marasini 2008       Evaluation of antivicrobial activities of medicinal plants against some fungi and antibiotic resistant bacteria
  297. Giridhari Rijal     2008       Urinary tract infection in diabetic microalbuminuric patients visiting B&B Hospital
  298. Santa Raj Khanal               2008       A comparative study of IGM capture Elisa and particle agglutination assay for the diagnosis of Japanese Encephalitis among some Nepalese patients
  299. Junu Koirala        2008       Study on antimicrobial activities of actinomycetes isolated from soils of different parts of khumbu region
  300. Manoj Khadka   2008       Estimation and projection oif the trend of HIV/AIDS in Nepal till 2010 using estimation and projection pakage (EPP) softwere
  301. Neelam Karna   2008       Cross-sectional study of urinary pathogens and their antibiotic susceptibility pattern with reference to extended spectreum beta lactamase (ESBL) producing strains in Kathmandu Model Hospital
  302. Naresh Maharjan             2008       Evaluation of antibacterial activities of medicinal plants
  303. Dinesh Maharjan             2008       The study of antibacterial activities of common spices
  304. Barsha Gurung  2008       Antibiotic susceptibility pattern of salmonella isolates from blood sample of patients visiting Shree Birendra Hospital, Chauni
  305. Minu K. C.           2008       Comparasion of blood culture and single slide agglutination widal test for the diagnosis of enteric fever
  306. Rupa Nepal         2008       Bacteriological profile and antibiotic susceptibility pattern of the isolates from infected burn wound at Kanti Children’s Hospital
  307. Nabaraj Dahal    2008       Comparative evaluation of macroscopic, microscopic, serological and cultural examination of csf in bacterial memingitis
  308. Prakash Shrestha             2008       Study on HIV and sexually transmitted infections among the female commercial sex workers of Kathmandu Valley
  309. Rishi Baniya        2008       Screening of antimicrobial activity of actinomycetes from soil samples of manang region of Nepal and their biological characterization
  310. Dhiraj Acharya   2008       Fluoroquinolone susceptibiligy pattern of the salmonella isolates from enteric fever patients visiting to National Public Health Laboratory, Nepal
  311. Krishna Prasad Pant        2009       Sero-epidemiology of Japanese encephalitis in some selectedhospitals of Nepal
  312. Ramesh Pun       2009       Sero-epidemiology of dengue virus infection in the post monsoon period I terai region of Nepal
  313. Supriya Sharma 2008       Bacteriological profile of urine of postoperative patients undergone open heart surgery at Shahid Gangalal National Heart Centre, Nepal
  314. Ashish Chandra Shrestha              2009       Transfusion transmissible infections among blood donors in Kathmandu, Nepal
  315. Sulochana Manandhar   2008       Bacteriological and histological profile of heart valves resected from infective endocarditis patients
  316. Shailaja Adhikari               2008       Prevalence of helicobacter pylori among dyspeptic patients attending Bir Hospital, Nepal
  317. Manita Aryal      2008       Isolation, identification and antibiotic sensitivity testing of salmonella serovars from enteric fever suspected patients visiting Bir Hospital
  318. Krishna Govinda Prajapati            2009       Antibiotic susceptibility pattern of salmonella from blood of suspected enteric fever patients attending Patan Hospital
  319. Hemanta Khanal               2009       Seroprevalence of hepatitis B virus among blood donors in Jhapa, Nepal
  320. Pratirodh Koirala              2009       Bacterioloigcal profiles of tracheal aspirates of patients attending National Institute of Neurolobical and allied sciences.
  321. Avishekh Gautam            2009       Evaluation of the three commercially availavle elisa test kits for the detection of Anti- HIV antibodies
  322. Archana Bhattarai            2009       Spectrum and antibiotic susceptibility pattern of bacterial isolates causing conjunctivitis among the patients visiting B.P. Koirala lions center for ophthalmic studies
  323. Rabindra Karki   2009       Cholera incidence among diarrhoeal patients visiting national public health laboratory, Nepal
  324. Anita Bhattarai  2009       Bacterioogy of chronic dacryocystitis and antibiotic susceptibiligy pattern of isolated bacteria
  325. Esha Shrestha    2009       Isolation and characterization of salmonella from drinking water samples of urban water supply system of Kathmandu
  326. Pratibha Thapa  2009       Strain typing of mycobacterium leprae isolates from Nepal uning variable number of tanden repeats
  327. Binita Adhikari   2009       Use of minisatellite genetic profiling with clinical analysis of leprosy patients in Nepal
Posted in Many More, Microbiology, Motivational, Writing/Blogging

यसैले म ‘शुक्ष्म जीवविज्ञान’ पढ्दैछु……

कल्पना गर्नुहोस्, अहिलेको अवस्था कस्तो हुन्थ्यो होला, यदि विज्ञानले ‘एन्टिबायोटिक’ पत्ता नलगाएको भए? लुइज पाश्चरले ‘पाश्चराइजेसन प्रक्रिया’ विकास नगरेको भए? अथवा ‘शुक्ष्म दर्शक यन्त्र’ अहिलेसम्म नबनेको भए? ………

Microbiologist: शुक्ष्मजीवविज्ञ

शुक्ष्म जीवविज्ञान अर्थात ‘माइक्रोबायोलोजी’ यति फराकिलो विषय हो, जो औषधी देखि फोहोर व्यवस्थापन (Bioremediation) सम्म हरेक क्षेत्रमा फैलिएको छ । यसले नछोएको क्षेत्र सायदै नहोला । विज्ञानमा यो नवआगन्तुक विषय भएतापनि यसको प्रयोग जानी या नजानी मानव सभ्यताको विकाससंगै गरिएको पाइन्छ । प्राचीन काल देखि नै अभ्यास गरिदै आइएको दहि बनाउने वा रक्सी पार्ने प्रक्रिया पनि ‘शुक्ष्म जीवविज्ञान’ नै हो । दुधबाट दहि बन्दै गर्दा वा अन्नबाट रक्सि बन्दै गर्दा हुने रासायनिक प्रक्रियामा सुक्ष्म जीवको भूमिका नै प्रमुख हुन्छ ।अहिलेको युग विज्ञान तथा प्रविधीको युग हो । विज्ञान तथा प्रविधी क्षेत्रमा माइक्रोबायोलोजीको प्रवेश यस क्षेत्रका लागि कोसेढुङ्गा साबित भएको छ ।

सामान्यतया ‘माइक्रोब’ वा ‘ब्याक्टेरिया’ भन्ने बित्तिकै धेरै मानिसको सोचाइमा ‘रोग लगाउने कारक’ भन्ने आउछ तर ‘ब्याक्टेरिया’ सधै हाम्रो ‘शत्रु’ मात्र होइनन्, यी त हाम्रा ‘असल साथि’ पनि हुन् । माइक्रोबायोलोजी विज्ञानको एउटा पाटो हो जसले नाङ्गो आँखाले देख्न नसकिने, माइक्रोमिटर (१ मिटरलाई १ लाख भाग लगाउदाको १ भाग) वा सो भन्दा सानो आकारमा हुने शुक्ष्म जीवहरुको अध्ययन गर्दछ । ती शुक्ष्मजीव (ब्याक्टेरिया, भाइरस, प्रोटोजोवा, यिस्ट, मोल्ड, एल्गी आदी), जसले रोग लगाउने, खाने कुराहरु सडाउने जस्ता हानिकारक अवस्थाहरु मात्र देखाउदैनन् विभिन्न क्षेत्रमा हामीलाई फाइदा पनि पुर्याउछन् । तिनै शुक्ष्मजीवविज्ञानमा विशेषज्ञता हासिल गरेका वैज्ञानिकलाई नै शुक्ष्म जीवविज्ञ (Microbiologist) भनिन्छ । आजको दिनमा ‘बायोटेक्नोलोजी’ सबैभन्दा तिब्र विकास भैरहेको उद्योगमा पर्दछ ।  रक्सि तथा पेय पदार्थ उद्योग, दुग्ध उद्योग, पाउरोटी तथा बेकरी उद्योग जस्ता खाद्य उद्योगहरुमा अहिले माइक्रोबायोलोजीको ब्यापक उपयोग भएको छ । महत्वपूर्ण औषधीहरु जस्तै ‘एन्टिबायोटिक’ मात्र होइन ‘इन्जाइम’, ‘हर्मोन’, ‘भिटामिन’, ‘भ्याक्सिन’ पनि शुक्ष्म जीव कै मद्दतले उत्पादन सम्भव भएको छ ।

तपाइँ हामी प्रत्येक क्षणमा शुक्ष्म जीवसंग जोडिएका छौं । हामीले लिने हावा, खाना वा पानीमा केहि संख्या देखि करोडौको संख्यामा शुक्ष्म जीवहरु हुन सक्छन । तिनीहरु सबै हानिकारक नै हुन्छन् भन्न सकिदैन । हाम्रो शरीरमा खासगरी बाहिरी छाला वा पाचन प्रणालीका विभिन्न अङ्गहरुमा “करिव २ केजी” शुक्ष्म जीवहरु बिना हानी बसेका हुन्छन् जसलाई ‘नर्मल फ्लोरा (Normal flora)’ भनिन्छ । तिनीहरु मध्ये कतिपयले हाम्रो शरीरलाई अत्यावश्यक रसायनहरू (इन्जाइम, भिटामिन आदि) उत्पादन गरेर हाम्रो शरीरभित्र हुने जैविक तथा रासायनिक प्रक्रियामा महत्वपूर्ण योगदान पुर्याएका हुन्छन् ।  त्यतिमात्र होइन तिनीहरुले हाम्रो शरीरमा प्रवेश गर्न सक्ने हानीकारक किटाणुलाई केहि हद सम्म मारिदिन्छन् । तर तिनीहरु पनि अवसरवादी बनिदिन सक्छन्, कमजोर प्रतिरक्षा प्रणाली भएको फाइदा उठाउदै कतिपय अवस्थामा रोग निम्त्याउन पनि सक्छन् ।

स्वास्थ्य क्षेत्रमा माइक्रोबायोलोजीको महत्वपूर्ण र प्रमुख भूमिका रहदै आएको छ । केहि वंशाणुगत रोगहरु बाहेक धेरैजसो रोगहरु शुक्ष्म जीव कै कारणले लाग्ने भएकोले त्यसको पहिचान मात्र होइन त्यसलाई हाम्रो शरीरबाट निर्मुल पार्न आवस्यक औषधी पनि माइक्रोबायोलोजीले उपलब्ध गराएको छ । विभन्न तरिका (Mechanism) मा शुक्ष्म जीवका बिरुद्ध काम गर्ने धेरै किसिमका औषधीहरु अहिलेसम्म पत्ता लागेका छन् र यो क्रम सधै जारि रहिरहन्छ । एउटा औषधी बन्दा, सुत्रिकरण (formulation) देखि बजार सम्म आउन धेरै प्रक्रियाहरु पार गर्नुपर्ने हुन्छ । हजारौंका संख्यामा परिक्षणका लागि आएका मध्ये सबै प्रक्रिया पार गरेर करिव १०, १२ वर्षमा १, २ को संख्यामा मात्र कुनै निश्चित रोगका नयाँ औषधी बजार सम्म आउँछन । त्यति मात्र होइन अहिले हामीले उपभोग गरिरहेका शुक्ष्म जीवका विरुद्द काम गर्ने औषधीहरु (antimicrobials) केहि समयावधी पछी तिनै शुक्ष्म जीवका विरुद्द काम गर्न नसक्ने बनिदिन्छन, अर्थात त्यसका विरुद्द शुक्ष्म जीवले प्रतिरोध गर्न सक्ने क्षमता (resistance) विकास गरिसकेका हुन्छन् ।  त्यसैले धेरै औषधी मध्येबाट छाटिएर करिव १०, १२ वर्षको अवधीमा नयाँ औषधी बन्ने र केहि समयपछी प्रत्येक औषधीको विकल्प खोज्नुपर्ने भएकोले यो क्षेत्रमा अनुसन्धान गर्ने जनशक्तिको सधै खाचो हुने गर्दछ । मधुमेह रोग अर्थात चिनी रोग (diabetes) का विरामीलाई दिईने इन्सुलिन पनि शुक्ष्म जीवकै मद्दतले उत्पादन (synthesis) गरिएको हो । बिषालु सर्पले टोकेमा दिईने औषधी (Anti-snake venom)  पनि शुक्ष्म जीवविज्ञानको एउटा प्रक्रिया (Immune response to veno­m) मा आधारित भएर उत्पादन गरिएको हो ।

बिरामी भएर हामी अस्पतालमा जाने बित्तिकै सबैभन्दा पहिला रोग लगाउने जीवाणु जाँच (Microbial examination) गरिन्छ । एउटा शुक्ष्म जीवविज्ञ (Microbiologist) ले उक्त जीवाणु पत्ता लगाउने मात्र होइन विरामीको शरीरमा भएको शुक्ष्म जीवका बिरुद्धमा कुन औषधीले काम गर्छ भन्ने परिक्षण (Antibiotic susceptibility test) पनि गर्नुपर्ने हुन्छ । यीनै परिक्षणको नतिजाको आधारमा डाक्टरले रिपोर्टमा सहि गर्ने र आवश्यक औषधी सिफारिस गर्ने गर्छ । त्यसैले स्वास्थ्य क्षेत्रतिर एउटा भनाइ चर्चित छ, “Doctors know nothing but do everything… physiologists know something and do something but microbiologists know everything but do nothing.”   अर्थात डाक्टरलाई केहि पनि थाहा हुदैन तर सबै काम गर्छ, फिजियोलोजिस्टलाई केहिमात्र थाहा हुन्छ त्यसैले केहिमात्र गर्छ; तर शुक्ष्म जीवविज्ञलाई सबै थाहा हुन्छ, केहि गर्दैन, अर्थात अस्पतालमा सबैभन्दा महत्वपूर्ण र प्रमुख भूमिका शुक्ष्म जीवविज्ञ कै हुने भएपनि, ऊ पर्दा पछाडिको पात्रको रुपमा मात्र देखिन्छ ।

खाद्य, दुग्ध, रक्सि तथा पेय पदार्थ उद्योगहरुमा धेरै पहिले देखि नै शुक्ष्म जीवलाई उपयोग गरिएको छ । दहि बनाउने क्रममा घरायसी उत्पादनमा हामीले जोर्डन (Inoculum) को रुपमा पुरानो दहि अलिकति मिसाएर नयाँ बनाएको अभ्यास त गरिरहेकै छौँ । यस प्रकृयामा पनि खासमा हामी शुक्ष्म जीवलाई नै मिसाएका हुन्छौँ, जसले दहि बन्ने प्रक्रियालाई सहज र छिटो बनाइदिन्छ । तर औद्योगिक वा व्यवसायिक उत्पादनमा शुक्ष्म जीवका विभिन्न प्रजातिहरु नै शुद्ध रुपमा प्रयोग गरिदै आइएको छ । रक्सीको घरयासी उत्पादनमा हामीले राख्ने मर्चामा पनि रक्सी बन्न चाहिने शुक्ष्म जीव (Saccharomyces cerevisiae, Aspergillus niger, A. oryzae, Mucor spp.) रहेका हुन्छन् । भने रक्सीको औद्योगिक उत्पादनमा यीनै शुक्ष्म जीवलाई छुट्टै (in the form of primary inoculums) शुद्ध रुपमा (in Pure Culture) मिसाइन्छ । पाउरोटी तथा वेकरी उद्योगमा पनि शुक्ष्म जीवको प्रयोग हुदै आएको छ । पछिल्लो पटक निकै चर्चामा रहेको तथा निरन्तर परिक्षण कै क्रममा रहेको, बिरुवा वा जनावरको बंशाणुगत गुण नै परिवर्तन गरेर तयार पारिएका खाद्यान्न (GM foods or Genetically Modified foods) ले विश्व खाद्यान्न अभाव तथा भोकमरीका बिरुद्दमा निकै महत्वपूर्ण भूमिका खेल्न सक्ने सम्भावना देखिन्छ । त्यस्तै खान मिल्ने एक कोषीय शुक्ष्मजीव (SPC, Single Cell Proteins)  पनि एउटा महत्वपूर्ण प्रोटिन स्रोत (Protein supplements) को रुपमा विकास भएको छ ।

शुक्ष्म जीवले कृषी क्षेत्रमा पनि महत्वपूर्ण फाइदा पुर्याएको छ । कोशेबालीको जरा (root nodule of legumes) मा पाइने शुक्ष्मजीवले वायुमण्डलको नाइट्रोजनलाई विरुवाले लिनसक्ने अवस्था (Ammonia or  Nitrate) मा पुर्याइदिन्छ, जसबाट हामीले हाम्रो शरीरलाई आवश्यक प्रोटिन (or amino acids), विरुवाबाट प्राप्त गर्दछौँ । शुक्ष्मजीवलाई मिसाएर एक प्रकारको मल (Bio-fertilizers) तयार पारिन्छ, जसले कुनै नकारात्मक असरबिना नै बिरुवालाई आवश्यक सम्पूर्ण तत्वहरु (Primary nutrients) उपलब्ध गराउछ । त्यतिमात्र होइन शुक्ष्म जीवलाई प्रयोग गरेर अर्गानिक तरिकाले  लाइकिरा मार्ने औषधी (Bio-pesticides) तयार पारिन्छ, जसले माटोमा भएका फाइदाजनक जीवाणुलाई बचाइराख्छ, साथै यो सजिलै सड्ने (biodegradable) भएकोले वातावरण तथा मानव स्वास्थ्यलाई समेत कुनै किसिमको असर गर्दैन ।

शुक्ष्मजीवलाई प्रदूषण नियन्त्रण (Pollution control) र जैवोपचारण (Bioremediation) मा पनि प्रयोग गरिएको हुन्छ । जसले हानिकारक फोहोर (hazardous pollutants) लाई हटाउन वा त्यसको असर कम (Neutralize) गर्न महत्वपूर्ण योगदान पुर्याएको हुन्छ । कुनै दुर्घटनाले समुद्रहरुमा तेल वा पेट्रोलियम पोखिदा समुद्रमा रहेका माछा तथा अन्य जीवहरु अक्सिजनको अभावले ठुलो सङ्ख्यामा मर्न सक्छन, त्यसले पारिस्थितिक प्रणाली (ecosystem) मा निकै ठुलो असर पार्छ । यसबाट बचाउनका निमित्त पनि शुक्ष्मजीवलाई नै प्रयोग गरिन्छ ।

शुक्ष्म जीवविज्ञानको आनुवंशिकी (Genetics), जीव रसायन (Biochemistry), पारिस्थितिक प्रणाली (Ecosystem), Immunology, Biotechnology, Molecular Biology लगायत क्षेत्रमा सिधा सम्बन्ध रहेको छ ।

Different Shapes of Microorganisms

यी र यस्तै हरेक क्षेत्रमा शुक्ष्म जीवविज्ञानको महत्वपूर्ण योगदान रहदै आएको छ ।  हाम्रो देशले पनि यस्तो अनुसन्धानमुखी शिक्षा (research based study) लाई प्राथमिकतामा राखेर पठनपाठन गराउनुपर्छ र उत्पादित जनशक्तिलाई कुनै खास काम गर्ने ठाउँ (platform) दिन सक्नुपर्छ । हरेक विकसित र अल्पविकसित देशहरुले अनुसन्धानका निमित्त आफ्नो पुरा बजेटको धेरै हिस्सा खर्च गरिरहेको अवस्थामा नेपालमा केहि वर्ष अघिमात्र विज्ञान तथा प्रविधी मन्त्रालय बनाइएको छ, त्यो पनि राजनीतिक नेताको रोजाइमा उक्त मन्त्रालय खासै पर्दैन ।अर्थात हाम्रो देशमा विज्ञान तथा प्रबिधीको महत्वलाई त्यत्ति बुझ्ने प्रयास नै गरिएको  छैन, यो सबैका निमित्त दुखदायी कुरा हो । विज्ञान तथा प्रविधीबिना देशको विकास असम्भव छ भन्ने कुरा सर्वविदितै हुँदा पनि यसलाई अझैसम्म प्राथमिकता नदिनु बिडम्बनापूर्ण छ । देशमा शिक्षित जनशक्ति, आफुले काम गर्ने ठाउ नै नपाएर बाहिर पलायन भएका छन् । किनकी यहाँ नीतिगत रुपमै काम गर्न सहज वातावरण छैन, राजनीतिक अस्थिरताले सहयोगी सरकारी नीति बन्न सकेका छैनन् । यसरी बौद्धिक शक्ति बाहिर पलायन हुनु देशको निम्ति धेरै ठुलो घाटा हो । हामी अहिलेसम्म पनि अरुले बनाएका औषधी खादैछौं, अरुले नै बनाएका इलोक्ट्रोनिक समान बोकिरहेका छौं । हाम्रो किन्ने हैसियत बढेको होला, तर हामी सृजनात्मक काममा जहाँको त्यहि छौं, तात्विक परिवर्तन आएको छैन । के हामीले गर्न नसक्ने नै हो त ? पक्कै पनि होइन, बाहिर पलायन भएका हाम्रै बौद्धिक शक्तिले विभिन्न विधामा विश्वमा हंगामा मच्चाइरहेका छन् । नयाँ नयाँ कृतिमानी राखेका छन्, के त्यो यहाँ सम्भव थिएन होला त ? यतातिर सम्बन्धित सबैको ध्यान जानु जरुरि छ ।

-चक्रपाणी भण्डारी, B.Sc. Microbiology (final year),
Amrit Science College, Tribhuvan University, Kathmandu


(गुल्मी जोहाङ १ परमानन्दनगरमा अवस्थित रुद्रावती स्कुलले प्रकाशन गर्न लागेको “रञ्‍जित रुद्रावती” नामक स्मारिकाको निमित्त तयार पारेको लेख ।)

ताजा अपडेटका लागि फेसबुकटुइटरमा जोडिनुहोस

Posted in Genetic engineering

Harvard student develops technique to diagnose cancer from a single drop of blood

What if a physician could effectively diagnose cancer from one drop of a patient’s blood??


Harvard student Neil Davey, A.B. ’18, has developed a technique that pushes the possibility of non-invasive cancer diagnosis one step closer to reality. Davey recently won a silver medal in the undergraduate section of the National Inventors Hall of Fame’s Collegiate Inventors Competition for his research project, “Early Cancer Diagnosis by the Detection of Circulating Tumor Cells using Drop-based Microfluidics.”

His technique involves injecting a tiny amount of blood into a microfluidic device to encapsulate single cells from the blood stream in individual microfluidic drops. Once the cells have been encapsulated, Davey uses a polymerase chain reaction (PCR), a common technique in molecular biology, to target and amplify fragments of cancer DNA within the drops. By linking DNA amplification to a fluorescent output, he canshine a laser onto the drops to detect and quantify brightness, which would indicate the presence of cancer DNA in a circulating tumor cell.

Davey developed this technique in the lab of mentor David Weitz, Mallinckrodt Professor of Physics and Applied Physics at the John A. Paulson School of Engineering and Applied Sciences.

“The advantage of this technology is that it is ultra-sensitive, so I can detect as few as one cancer cell from a billion normal cells in the blood,” he said. “The process is also very specific. One can uniquely detect a wide range of cancers using this DNA amplification technology.


The technique could hold huge implications in the world of cancer diagnostics, which currently relies primarily on invasive and dangerous tumorbiopsies.

Microfluidics is much easier and cheaper than traditional methods, since the test uses only tiny amounts of reagents and takes 30 to 60 minutes to complete.

The technology is currently about 90 percent accurate, but that accuracy can be improved if the test is refined to target more genes of the cancer cell, Davey said. “Because this technology is in an engineering platform, it is pretty universal. We tested the platform itself on prostate cancer and colorectal cancer, but it can be used on any disease, as well,” he said. Davey, who developed an interest in biology while working as a high school intern at the Food and Drug Administration, is looking forward to studying additional applications of microfluidics.

The technology can be used to isolate specific cancer genomes by sorting bright drops out of the mix, enabling scientists to learn more about the nature of the disease. It can also be used to identify specific mutations of the cancer genome, which could help doctors determine which medications would be most effective for a patient.

For Davey, who recently declared an economics concentration with a secondary field in statistics, the opportunity to use his knowledge to potentially improve the lives of cancer patients has been extremely rewarding. “The coolest thing about this project is that it is so interdisciplinary, involving biology, medicine, and engineering,” he said. “Looking downstream, we could someday use this technique to provide much more personalized cancer treatment.”

Source: Harvard, School of engineering & applied sciences

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Posted in Microbiology


Media are of different types on consistency and chemical composition.
A. On Consistency:
1. Solid Media
Advantages of solid media:
(a) Bacteria may be identified by studying the colony character
(b) Mixed bacteria can be separated. Solid media is used for the isolation of bacteria as pure culture. ‘Agar’ is most commonly used to prepare solid media. Agar is polysaccharide extract obtained from seaweed. Agar is an ideal solidifying agent as it is :
(a) Bacteriologically inert, i.e. no influence on bacterial growth,
(b) It remains solid at 37°C, and
(c) It is transparent.
2. Liquid Media. It is used for profuse growth, e.g. blood culture in liquid media. Mixed organisms cannot be separated.

B. On Chemical Composition :
1. Routine Laboratory Media
2. Synthetic Media. These are chemically defined media prepared from pure chemical substances. It is used in research work.

These are classified into six types
(1) Basal media,
(2) Enriched media,
(3) Selective media,
(4) Indicator media,
(5) Transport media, and
(6) Storage media.

1. BASAL MEDIA: Basal media are those that may be used for growth (culture) of bacteria that do not need enrichment of the media.
Examples: Nutrient broth, nutrient agar and peptone water. Staphylococcus and Enterobacteriaceae grow in these media.
2. ENRICHED MEDIA: The media are enriched usually by adding blood, serum or egg.
Examples: Enriched media are blood agar and Lowenstein-Jensen media. Streptococci grow in blood agar media.

3. SELECTIVE MEDIA: These media favour the growth of a particular bacterium by inhibiting the growth of undesired bacteria and allowing growth of desirable bacteria.
Examples: MacConkey agar, Lowenstein-Jensen media, tellurite media (Tellurite inhibits the growth of most of the throat organisms except diphtheria bacilli). Antibiotic may be added to
a medium for inhibition.

4. INDICATOR (DIFFERENTIAL) MEDIA: An indicator is included in the medium. A particular organism causes change in the
Example. blood, neutral red,tellurite.
Examples: Blood agar and MacConkey agar are indicator media.

5. TRANSPORT MEDIA: These media are used when specimen cannot be cultured soon
after collection.
Examples: Cary-Blair medium, Amies medium, Stuart medium.

6. STORAGE MEDIA: Media used for storing the bacteria for a long period of time.
Examples: Egg saline medium, chalk cooked meat broth.
Nutrient Broth. 500 g meat,
Example: ox heart is minced and mixed with 1 litre water. 10 g peptone and 5 g sodium chloride are added, pH is adjusted to 7.3.

(1) As a basal media for the preparation of other media,
(2) To study soluble products of bacteria.

Nutrient Agar: It is solid at 37°C. 2.5% agar is added in nutrient broth. It is heated at 100°C to melt the agar and then cooled. Peptone Water. Peptone 1% and sodium chloride 0.5%. It is used as base for sugar media and to test indole formation.

Blood Agar: Most commonly used medium. 5-10% defibrinated sheep or horse blood is added to melted agar at 45-50°C. Blood acts
as an enrichment material and also as an indicator. Certain bacteria when grown in blood agar produce haemolysis around their colonies. Certain bacteria produce no haemolysis.
Types of changes:
(a) beta (p) haemolysis. The colony is surrounded by a clear zone of complete haemolysis,
Example: Streptococcus pyogenes is a beta haemolytic streptococci,

(b) Alpha (a) haemolysis. The colony is surrounded by a zone of greenish discolouration due to formation of biliverdin
Example: Viridane streptococci,
(c). Gamma (y) haemolysis or, No haemolysis. There is no change in the medium surrounding the colony, Chocolate Agar or Heated Blood agar. Prepared by heating blood agar. It is used for culture of Pneumococcus, Gonococcus,
Meningococcus and Haemophilus. Heating the blood inactivates inhibitor of growths.

MacConkey Agar: Most commonly used for enterobacteriaceae. It contains agar, peptone, sodium chloride, bile salt, lactose and neutral red. It is a selective and indicator medium :
(1) Selective as bile salt does not inhibit the growth of enterobactericeae but inhibits
growth of many other bacteria.

(2) Indicator medium as the colonies of bacteria that ferment lactose take a pink colour due to production of acid. Acid turns
the indicator neutral red to pink. These bacteria are called ‘lactose fermenter’,
Example Escherichia coli. Colourless colony indicates that lactose is not fermented, i.e. the
bacterium is non-lactose fermenter,
Example: Salmonella, Shigella,Vibrio.

Mueller Hinton Agar: Disc diffusion sensitivity tests for antimicrobial drugs should be carried out on this media as per WHO recommendation to promote reproducibility and comparability of results.

Hiss’s Serum Water Medium: This medium is used to study the fermentation reactions of
bacteria which can not grow in peptone water sugar media,
Example  pneumococcus, Neiseria Corynebacterium

Lowenstein-Jensen Medium: It is used to culture tubercle bacilli. It contains egg, malachite green and glycerol.
(1) Egg is an enrichment material which stimulates the growth of tubercle bacilli,
(2) Malachite green inhibits growth of organisms other than
(3) Glycerol promotes the growth of Mycobacterium tuberculosis but not Mycobacterium bovis.

Dubos Medium: This liquid medium is used for tubercle bacilli. In this medium drug sensitivity of tubercle bacilli can be carried out. It contains ‘tween 80’, bovine serum albumin, casein hydrolysate, asparagin and
salts. Tween 80 causes dispersed growth and bovine albumin causes rapid growth. Loeffler Serum. Serum is used for enrichment. Diphtheria bacilli grow in this medium in 6 hours when the secondary bacteria do not grow. It is used for rapid diagnosis of diphtheria and to demonstrate volutin granules. It contains sheep, ox or horse serum.

Tellurite Blood Agar: It is used as a selective medium for isolation of Cotynebacterium
diphtheriae. Tellurite inhibits the growth of most secondary bacteria without an inhibitory
effect on diphtheria bacilli. It is also an indicator medium as the diphtheria bacilli produce black colonies. Tellurite metabolized
to tellbrism, which has black colour.

EMB (Eosin-methylene blue) Agar: A selective and differential medium for enteric Gram-negative rods. Lactose-fermenting
colonies are coloured and nonlactose-fermenting colonies are non pigmented. Selects against gram positive bacteria.

XLD (Xylose Lysine Deoxychoiate). It is used to isolate Salmonella and Shigella species from stool specimens. This is a selective media.

SS (Salmonella-Shigella) Agar. It is a selective medium used to isolate Salmonella and Shigella species. SS Agar with additional
bile salt is used if Yersinia enterocolitica is suspected.

DCA (Desoxycholate Citrate Agar): It is used for isolation of Salmonella and Shigella. The
other enteric bacteria are mostly inhibited (a selective medium). It is also a differential (indicator) medium due to presence of lactose and neutral red.

Tetrathionate Broth: This medium is used for isolating Salmonella from stool. It acts as a
selective medium. It inhibits normal intestinal bacteria and permits multiplication of Salmonella.

Selenite F Broth. Uses and functions are same as that of tetrathionate broth.

Thiosulphate-Citrate-Bile-Sucrose (TCBS) Agar: TCBS agar is a selective medium used to isolate Vibrio cholerae and other Vibrio species from stool.

Charcoal-yeast agar: Used for Legionella pneumophila. Increased concentration of iron
and cysteine allows growth.

Tellurite-Gelatin Agar Medium (TGAM): It may be used as transport, selective and indicator medium.

Alkaline peptone water: See under Vibrio.

Campylobacter Medium. This selective medium is used to isolate Campylobacter jejuni
and Campylobacter coli from stool.

Cary-Blair Medium: It is used as a transport medium for faeces that may contain Salmonella, Shigella, Vibrio or Campylobacter

Amies medium is used for Gonococci and other pathogens.

Peptone Water Sugar Media: These indicator media are used to study ‘Sugar fermentation’. 1 % solution of a sugar (lactose,glucose, mannitol etc) is added to peptone water containing Andrade’s indicator in a test tube. A small inverted Durham tube is placed in the medium. The media are colourless. After culture, change of a medium to red colour
indicates acid production. Gas, if produced collects in Durham tube.

Motility Indole Urea (MIU) Medium: This is used to differentiate enterobacteria species by their motility, urease, and indole reactions.

TSI (Triple sugar iron) Agar

KIA (Kligler Iron Agar). This is a differential slope medium used in the identification of enteric bacteria. The reactions are based on the fermentation of lactose and glucose and the production of hydrogen sulphide.

Christensen’s Urea Medium: This is used to identify urea splitting organisms,
A purple pink colour indicates urea splitting

Bordet-Gengou Medium: This medium is used for culture of Bordetella pertussis. Increased
concentration of blood allows growth. It contains agar, potato, sodium chloride, glycerol, peptone and 50% horse blood. Penicillin may be added to it.


Posted in Microbiology


HIV particles are effectively trapped by the cervicovaginal mucus from women who harbor
a particular vaginal bacteria species, Lactobacillus crispatus. The findings, published this week in mBio, an online open-access
journal of the American Society for Microbiology, could lead to new ways to reduce or block vaginal transmission of HIV and other sexually transmitted infections (STIs). “Mucosal surfaces, such as the lung, gastrointestinal tract, or female reproductive tract, are where most infections take place,”
says Sam Lai, assistant professor of pharmacy and engineering at University of North Carolina
at Chapel Hill and senior author on the study. “Our bodies secrete over six liters of mucus
everyday as a first line of defense.”Cervicovaginal mucus (CVM) can act as a barrier to prevent pathogens from reaching the underlying vaginal wall cells, but the barrier properties vary greatly from woman to woman and even at different times in the same woman.

Lai and his collaborators wanted to know what accounts for those differences. They collected fresh CVM samples from 31
women of reproductive age, measured various properties of the mucus and used high- resolution, time-lapse microscopy to test whether fluorescent HIV pseudovirus particles became trapped in the mucus or diffused
freely. The researchers observed two distinct populations of CVM samples, one that was very
good at trapping HIV and one that was not. Trapping of HIV did not correlate to the mucus’ pH, total lactic acid, or Nugent score, a
rough measure of vaginal ‘health’ that reflects how many Lactobacillus bacteria are present
compared to other microbes.
One difference between the two groups, higher levels of D-lactic acid in the group that trapped HIV, stood out to the researchers
because humans cannot make D-lactic acid.

The team suspected that different bacteria living within the mucus layer were responsible for differences in D-lactic acid. When they sequenced ribosomal genes to identify the
bacteria within each sample, the researchers found that the samples fell again into two
groups. L. crispatus bacteria dominated the CVM that trapped HIV. In contrast, CVM that failed to trap HIV either possessed a different Lactobacillus species, L. iners, or had multiple bacterial species present including Gardnerella vaginalis —both conditions that are frequently
associated with bacterial vaginosis. “I was really surprised by how slight differences between Lactobacillus species make a very substantial difference in the barrier properties of mucus,” says Lai. In the clinical setting, there is a clear link between bacterial
vaginosis and having a higher risk of acquiring and transmitting STI’s. Historically, Lai explains, gynecologists considered vaginal
microflora to be healthy if it was dominated by any Lactobacillus species. “But our work shows
that from a mucus barrier perspective, that is not a good enough distinction,” says Lai.

Healthcare workers should be aware that women who harbor L. iners probably have a substantially higher risk of acquiring STIs. And conversely, a L. crispatus dominant microflora may be more protective against HIV and STIs than previously appreciated. The group also showed that L. crispatus caused
CVM to be more ‘sticky’ against HIV particles— rather than making a tighter mucus mesh. The
barrier function was not unique to HIV particles and would likely trap other enveloped viruses as well.

Lai notes that CVM can be thought of as a “biological condom” which could potentially be reinforced by altering a woman’s vaginal microbiota. “If we could find a way to tilt the battle in favor of L. crispatus in women, then we would be increasing the barrier properties of their CVM, and improve protection against STIs,” he says. Richard Cone, a biophysicist at Johns Hopkins University in Baltimore and another author on the study, is working on solutions that might deliver a sustained release of lactic acid to the vagina, which would encourage L. crispatus to thrive.