Research focus is on the development of novel vaccine candidate
against enteric pathogens like Vibrio cholerae,
Shigella, Salmonella, Escherichia coli, and
Campylobacter for the livestock and human.
Laboratory has identified a number of potential vaccine
candidates like outer membrane vesicles, heat killed bacteria,
live attenuated bacteria, chitosan-alginate nanoparticle.
Special expertise on outer membrane vesicles based studies on
various animal models, like Mouse, Rat, Guinea pig, Rabbit,
Chicken and Zebra fish.
Long path programme of the laboratory is to develop a single
vaccine candidate against all enteric pathogens.
In 1992, after completion of Master degree in Human Physiology
from Dept. of Physiology, University College of Science &
Technology, Calcutta University, he joined Division of
Bacteriology, National Institute of Cholera and Enteric Diseases
(NICED), an integral Institute of the Indian Council of Medical
Research and a WHO Collaborating Centre for Research and
Training in Diarrhoeal Diseases, Kolkata, India, for Ph. D.
degree under supervision of Dr. GB Nair. In 1996, he joined as
Associate Professor in Dept. of Physiology, College of Medical
Sciences-Nepal, where he devoted himself entirely in teaching
medical students. Meanwhile, Dr. Koley got an opportunity for
Post-Doctoral research in the laboratory of Prof Dipak K Sarkar,
Dept Animal Sciences, Rutgers - The State University of New
Jersey, New Brunswick, USA. After completion of one year in
Rutgers University, Dr. Koley moved to Boston, joined
Gastroenterology Section of Harvard Medical School, as Research
Associate and worked there on "Molecular mechanism of Barrett's
oesophagus and to identify therapeutic target for Adenocarcinoma"
under leadership of Prof. R K Goyal, renowned
Published 70 original papers and 40 abstracts in his credit.
Secured patent for a process for the preparation of Cholera
Vaccine-VA1.3 (European Patent Office; Patent No.-
97309957.5-2105 on 19/05/98) in pre-doctoral research in NICED
Received Young Scientist Award in IUPS International Congress,
Christchurch, New Zealand, August 2001.
Awarded Oration Lecture: "Dr. (Mrs.) Chitralekha Mukherjee
Memorial Oration-2010" and given lecture at St. John's Medical
College, Bangalore on 16th December 2010
Recently developed Shigella Vaccine and applied patent through
Indian council of Medical Research, New Delhi. Patent
application for: "A multiple outer membrane vesicles (MOMV) of
Shigellae as a Novel Candidate vaccine" ICMR New Delhi. (Patent
application no. 1652/Del/2013 dated 31.05.2013)
International patent application: PCT patent application titled
‘A Multi-Serotype Outer Membrane Vesicles (MOMV) of shigellae as
a novel candidate vaccine' (PCT/IN2014/000369).
Patent application for: "Alginate chitosan Nano formulation of
Omp-A, a Shigella protein subunit vaccine" ICMR New Delhi.
(Patent application # 201611015219/ IPR/NICED/OmpA/329 June,
Invited special lecture at "Asian Society of Diarrhoeal Disease
and Nutrition" conference (ASCODD) at Kochi between October
30,2017 to November 1, 2017.
Invited Lecture on "Shigella Vaccine" Occasion of MSD-Hilleman
Laboratory Science day workshop on 2nd Nov 2017 at Imperial
Hotel, New Delhi.
Howlader DR, Koley H, Maiti S, Bhaumik U, Mukherjee P,
Dutta S. A brief review on the immunological scenario and recent
developmental status of vaccines against enteric fever. Vaccine.
2017 Nov 7;35(47):6359-6366.
Mitobe J, Sinha R, Mitra S, Nag D, Saito N, Shimuta K,
Koizumi N, Koley H. An attenuated Shigella mutant lacking the
RNA-binding protein Hfq provides cross protection against
Shigella strains of broad serotype. PLoSNegl Trop Dis. 2017 Jul
Sinha R, Howlader DR, Ta A, Mitra S, Das S, Koley H.
Retinoic acid pre-treatment down regulates V. cholerae outer
membrane vesicles induced acute inflammation and enhances
mucosal immunity. Vaccine. 2017 Jun16;35(28):3534-3547.
Ta A, Thakur BK, Dutta P, Sinha R, Koley H, Das S.
Double-stranded RNA induces cathelicidin expression in the
intestinal epithelial cells through phosphatidylinositol
3-kinase-protein kinase Cζ-Sp1 pathway and ameliorates
shigellosis in mice. Cell Signal. 2017 Jul;35:140-153.
Mandal RS, Ta A, Sinha R, Theeya N, Ghosh A, Tasneem M, Bhunia
A, Koley H, Das S. Ribavirin suppresses bacterial virulence by
targeting LysR-type transcriptional regulators. Sci Rep. 2016
Roy S, Patra T, Golder T, Chatterjee S, Koley H, Nandy RK.
Characterization of the gluconate utilization system of Vibrio
cholerae with special reference to virulence modulation. Pathog
Dis. 2016 Nov;74(8).
Ghosh A, Koley H, Pal A. The Role of Vibrio
choleraecholera Haemagglutinin Protease (HAP) in
Extra-Intestinal Infection. J ClinDiagn Res. 2016 Sep;10(9)
Chourashi R, Mondal M, Sinha R, Debnath A, Das S, Koley H,
Chatterjee NS. Role of a sensor histidine kinase ChiS of Vibrio
cholerae in pathogenesis. Int J MedMicrobiol. 2016
Bhattacharya D, Bhattacharya S, Patra MM, Chakravorty S, Sarkar
S, ChakrabortyW, Koley H, Gachhui R. Antibacterial Activity of
Polyphenolic Fraction of Kombucha Against Enteric Bacterial
Pathogens. CurrMicrobiol. 2016
Howlader DR, Sinha R, Nag D, Majumder N, Mukherjee P, Bhaumik U,
MaitiS,Withey JH, Koley H. Zebrafish as a novel model for
non-typhoidal Salmonella pathogenesis, transmission and vaccine
efficacy. Vaccine. 2016 Sep30;34(42):5099-5106.
Sarkar P, Acharyya S, Banerjee A, Patra A, Thankamani K,
Koley H, Bag PK. Intracellular, biofilm-inhibitory and
membrane-damaging activities of nimbolide isolated from
Azadirachta indica A. Juss (Meliaceae) against meticillin-resistant
Staphylococcus aureus. J Med Microbiol. 2016
Koley H, Ghosh P, Sinha R, Mitra S, Mukherjee P, Howlader
DR, Chaki C, Nag D. Mice with Streptozotocin-Induced
Hyperglycemia are Susceptible to Invasive Enteric Bacterial
Infection. Jpn J Infect Dis. 2017 Jan 24;70(1):111-114.
Nag D, Sinha R, Mitra S, Barman S, Takeda Y, Shinoda S, Chakrabarti MK, Koley H. 2015. Heat killed multi-serotype
Shigellaimmunogens induced humoral immunity and protection against heterologous challenge in rabbit model. Immunobiology.220:1275-83.
Jaiswal A, Sarkar S, Das P, Nandy S, Koley H, Sarkar B. 2015. Trends in the genomic epidemiology of Vibrio cholerae O1
isolated worldwide since 1961. Int J Antimicrob Agents 46:460-4.
Withey JH, Nag D, Plecha SC, Sinha R, Koley H. 2015. Conjugated linoleic acid reduces cholera toxin production in vitro
and in vivo by inhibiting Vibrio choleraeToxT activity. Antimicrob Agents Chemother. 59:7471-6.
Sinha R, Koley H, Nag D, Mitra S, Mukhopadhyay AK,
Chattopadhyay B. 2015 Pentavalent outer membrane vesicles of Vibrio
cholerae induce adaptive immune response and protective efficacy in both
adult and passive suckling mice models. Microbes Infect.
Bhattacharya D, Dey S, Kadam S, Kalal S, Jali S, Koley
H, Sinha R, Nag D, Kholkute SD, Roy S. 2015 Isolation of
NDM-1-producing multidrug-resistant Pseudomonas putida from a paediatric
case of acute gastroenteritis, India. New Microbes New Infect. Feb
Rajpara N, Kutar BM, Sinha R, Nag D, Koley H,
Ramamurthy T, Bhardwaj AK. 2015 Role of integrons, plasmids and SXT
elements in multidrug resistance of Vibrio cholerae and
Providenciavermicola obtained from a clinical isolate of diarrhea. Front
Microbiol. Feb 17;6:57.
Mondal M, D Nag, H Koley, DR Saha, Chatterjee NS. 2014. The Vibrio choleraeExtracellular Chitinase
ChiA2 Is Important for Survival and Pathogenesis in the Host Intestine. PLoS One. 9:e103119.
Kanungo S, B Sen, T Ramamurthy, D Sur, B Manna, GP Pazhani, G Chowdhury, P Jhunjhunwala, RK Nandy, HKoley, MK Bhattacharya, S Gupta, G Goel, B Dey, M T,
GB Nair, A Ghosh, D Mahalanabis.2014.Safety and immunogenicity of a live oral recombinant cholera vaccine VA1.4: a randomized, placebo
controlled trial in healthy adults in a cholera endemic area in Kolkata, India. PLoS One. 9:e99381).
Barman S, H Koley, D Nag, S Shinoda, GB Nair, Y Takeda. 2014. Passive immunity with multi-serotype heat-killed Shigellae
in neonatal mice. MicrobiolImmunol. 58:463-6.
Koley H, N Ray, G Chowdhury, S Barman, S Mitra, T Ramamurthy, AK Mukhopadhyay, BL Sarkar, R Katyal, P Das, S Panda, S Ghosh.2014.
Outbreak of cholera caused by Vibrio cholerae O1 El Tor variant strain in Bihar, India. Jpn J Infect Dis.67:221-6.
Jaiswal A, H. Koley, S Mitra, DR Saha, B Sarkar. 2014.Comparative analysis of different oral approaches to treat
Vibrio cholerae infection in adult mice. Int J Med Microbiol. 304:422-30.
Ghosh P, A Naha, S Basak, S Ghosh, T Ramamurthy, H. Koley, RK Nandy, S Shinoda, H Watanabe, AK Mukhopadhyay. 2014. Haitian
variant tcpA in Vibrio cholerae O1 El Tor strains in Kolkata, India. J ClinMicrobiol.52:1020-1.
Mitra S, MK Chakrabarti, H. Koley
2013 Multi-serotype outer membrane vesicles of Shigellae confer passive
protection to the neonatal mice against shigellosis. Vaccine. 31:
Sheikh IA, H. Koley, MK Chakrabarti,
KM Hoque. 2013 The Epac1 signaling pathway regulates Cl- secretion via
modulation of apical KCNN4c channels in diarrhea. J Biol Chem. 288:
Das P, AK Singh, S Mukherjee, K Rajendran,
DR Saha, H. Koley, S Basu. 2013 Composition of Escherichia coli
population in the neonatal gut: phylogroups and virulence determinants.
J Med Microbiol. 62: 1680-1687.
Mukherjee S, H. Koley, S Barman, S
Mitra, S Datta, S Ghosh, D Paul, P Dhar. 2013 Oxalis corniculata (Oxalidaceae)
leaf extract exerts in vitro antimicrobial and in vivo anticolonizing
activities against Shigella dysenteriae 1 (NT4907) and Shigella flexneri
2a (2457T) in induced diarrhea in suckling mice. J Med Food. 16:
Barman S, H. Koley, T Ramamurthy, MK
Chakrabarti, S Shinoda, GB Nair, Y Takeda. 2013 Protective immunity by
oral immunization with heat-killed Shigella strains in a guinea pig
colitis model. Microbiol Immunol. 57: 762-771.
Rajpara N, K Vinothkumar, P Mohanty, AK
Singh, R Singh, R Sinha, D Nag, H. Koley, A Kushwaha Bhardwaj.
2013 Synergistic Effect of Various Virulence Factors Leading to High
Toxicity of Environmental V. cholerae Non-O1/ Non-O139 Isolates Lacking
ctx Gene : Comparative Study with Clinical Strains. PLoS One. 8:
DR Saha, S Guin, R Krishnan, D Nag, H.
Koley, S Shinoda, T Ramamurthy. 2013 Inflammatory diarrhea due to
enteroaggregative Escherichia coli: evidence from clinical and mice
model studies. Gut Pathog. 5: 36.
Jaiswal A, H. Koley, A Ghosh, A Palit,
B Sarkar 2013 Efficacy of cocktail phage therapy in treating
Vibrio cholerae infection in rabbit model. Microbes Infect. 15:
Mitra S, DR Saha, A Pal, Niyogi SK, U Mitra,
H. Koley.2012 Hemagglutinating activity is directly
correlated with colonization ability of shigellae in suckling mouse
model. Can J Microbiol. 58: 1159-1166.
Mitra S, S Barman, D Nag, R Sinha, DR Saha,
H. Koley. 2012 Outer membrane vesicles of Shigella boydii type 4
induce passive immunity in neonatal mice. FEMS Immunol Med Microbiol.
China R, S Mukherjee, S Sen, S Bose, S Datta,
H. Koley, S Ghosh, P Dhar. 2012 Antimicrobial activity of
Sesbania grandiflora flower polyphenol extracts on some pathogenic
bacteria and growth stimulatory effect on the probiotic organism
Lactobacillus acidophilus. Microbiol Res. 167: 500-506.
Patra T, H. Koley, T Ramamurthy, AC
Ghose, RK Nandy. 2012 The Entner-Doudoroff pathway is obligatory
for gluconate utilization and contributes to the pathogenicity of Vibrio
cholerae. J Bacteriol. 194: 3377-3385.
Dey T K , S. Ghosh , M. Ghosh, H. Koley,
P. Dhar 2012
Comparative study of gastrointestinal absorption of EPA DHA rich fish
oil from nano and conventional emulsion formulation in rats. Food
Research International , 49: 72-79
Barman S, DR Saha, T Ramamurthy, H. Koley.
2011 Development of a new guinea-pig model of shigellosis. FEMS
Immunol Med Microbiol. 62: 304-314.
Barman S, R Kumar, G Chowdhury, DR Saha, T
Wajima, T Hamabata, R Tamamurthy, GB Nair, Y Takeda, H. Koley. 2011
A live noninvasive Shigella dysenteriae 1 strain induces homologous
protective immunity in a guinea pig colitis model. Microbiol Immunol.
Mukherjee, Chaki S. Barman S., S Das., H.
Koley and Dastidar Ghosh, 2011 Effective elimination of drug
resistance genes in pathogenic Pseudomonas aeruginosa by antipsycholic
agent thioridazine . Current Research in Bacteriology
Ghosh S, Chakraborty K, Nagaraja T, Basak S,
Koley H , Dutta S, Mitra U, Das S. 2011. An adhesion
protein of Salmonella enterica serovar Typhi is required for
pathogenesis and potential target for vaccine development. Proc Natl
Acad Sci USA 108: 3348-3353.
Panda S, Pati KK, Bhattacharya MK, Koley H,
Pahari S, Nair GB. 2011 Rapid situation response assessment of
diarrhea outbreak in a coastal district following tropical cyclone AILA
in India. Indian J Med Res. 133: 395-400.
Roy, N., S Barman, A Ghosh, A Pal, K
Chakraborty, SS Das, DR Saha, S Yamasaki, H. Koley. 2010.
Immunogenicity and protective efficacy of Vibrio cholerae outer
membrane vesicles in rabbit model. FEMS Immunol Med Microbiol. 60:
Barman, S., S Chatterjee, G Chowdhury, T
Ramamurthy, SK Niyogi, R Kumar, H. Koley2010.
Plasmid-mediated streptomycin and sulfamethoxazole resistance in
Shigella flexneri 3a. Int J Antimicrob Agents. 36: 348-351.
Ghosh-Banerjee, J., M Senoh, T Takahashi, T
Hamabata, S Barman, H. Koley, Mukhopadhyay AK, Ramamurthy T,
Chatterjee S, Asakura M, Yamasaki S, Nair GB,Takeda Y. 2010 .
Cholera toxin production by the El Tor variant of Vibrio cholerae
O1compared to prototype El Tor and classical biotypes. J Clin
Syngkon A, S Elluri, H. Koley, P K
Rompikuntal, DR Saha, MK Chakrabarti, RK Bhadra , SN Wai, A Pal. 2010
Studies on a novel serine protease of a ?hapA?prtV Vibrio cholerae
O1 strain and its role in hemorrhagic response in the rabbit ileal loop
model. PLoS One. 5(9). e13122.
Shammas, M. A., Shmookler Reis RJ, H.
Koley, Batchu RB, Li C, Munshi NC. 2009. Dysfunctional
homologous recombination mediates genomic instability and progression in
myeloma. Blood. 113: 2290-7.
Bhowmick, T.S., H. Koley, M. Das, D.
R. Saha, B. L. Sarkar. 2009. Pathogenic potential of vibriophages
against an experimental infection with Vibrio cholerae O1 in the RITARD
model. Int J Antimicrob Agents. 33: 569-573.
Koley, H., S. Barman, N. Roy, D. R.
Saha, R. Kumar. 2009. The efficacy and immunogenicity of a live
transconjugant hybrid strain of Shigella dysenteriae type 1 in two
animal models. World J. Microbiol Biotechnol. 25: 679-686.
Chakraborty, K., Ghosh S, H. Koley,
Mukhopadhyay AK, Ramamurthy T, Saha DR, Mukhopadhyay D, Roychowdhury S,
Hamabata T, Takeda Y, Das S. 2008. Bacterial exotoxins
downregulate cathelicidin (hCAP-18/LL-37) and human beta-defensin 1
(HBD-1) expression in the intestinal epithelial cells. Cell Microbiol.
Banerjee, S., Chattopadhyay R, Ghosh A, H.
Koley, Panda K, Roy S, Chattopadhyay D, Chatterjee IB. 2008
.Cellular and molecular mechanisms of cigarette smoke-induced lung
damage and prevention by vitamin C. J Inflamm 11; 5: 21.
Shammas, M. A., H. Koley, R. C. Bertheau,
P. Neri, M. Fulciniti, P. Tassone, S. Blotta, A. Protopopov, C. Mitsiades, R. B. Batchu,
K. C. Anderson, A. Chin, S. Gryaznov, N. C. Munshi. 2008. Telomerase
inhibitor GRN163L inhibits myeloma cell growth in vitro and in vivo.
Koley, H., Soumik Barman, N. Roy, D.
R. Saha, R. Kumar. 2008. The efficacy and immunogenicity of a live
transconjugant hybrid strain of Shigella dysenteriae type 1 in two
animal models. World J. Microbiol Biotechnol. 25: 679-686.
Bhowmick, R., A. Ghosal, B. Das,
D. R. Saha, S. Ganguly, R. K. Nandy, R. K. Bhadra, N. S. Chatterjee. 2008
Intestinal adherence of Vibrio cholerae involves a coordinated
interaction between colonization factor GbpA and mucin. Infect Immun.
Shammas, M. A., P. Neri, H. Koley,
R. B. Batchu,
R. C. Bertheau, V. Munshi, R. Prabhala, M. Fulciniti, Y. T. Tai, S. P. Treon,
R. K. Goyal, K. C. Anderson, N. C. Munshi. 2006. Specific killing of multiple
myeloma cells by (-) epigallocatechin-3-gallate extracted from green
tea: biologic activity and therapeutic implications. Blood. 108: 2804-10.
Ghosh, A., D. R. Saha, K. M. Hoque, M. Asakuna,
S. Yamasaki, H. Koley,
S. S. Das, M. K. Chakrabarti, A. Pal. 2006.
Enterotoxigenicity of mature 45-kilodalton and processed 35-kilodalton
forms of hemagglutinin protease purified from a cholera toxin
gene-negative Vibrio cholerae non-O1, non-O139 strain. Infect Immun.
Shammas, M. A., H. Koley,
R. B. Batchu,
R. C. Bertheau, A. Protopopov, N. C. Munshi, R. K. Goyal. 2005. Telomerase
inhibition by siRNA causes senescence and apoptosis in Barrett's
adenocarcinoma cells: mechanism and therapeutic potential. Mol. Cancer.
Koley, H., M. A. Shammas, D. G. Beer,
C. Li, R. K. Goyal, N. C. Munshi. 2004. Growth arrest, apoptosis and telomere
shortening of Barrett's-associated adenocarcinoma cells by a telomerase
inhibitor. Gastroenterology. 126: 1337-46.
Shammas, M. A., Reis R. J. Shmookler, C. Li,
L. H. Hurley, K. C. Anderson, N. C. Munshi. 2004 Telomerase
inhibition and cell growth arrest after telomestatin treatment in
multiple myeloma. Clin Cancer Res. 10: 770-6.
Shammas, M. A., Reis R. J. Shmookler, M. Akiyama,
D. Chauhan, T. Hideshima, R. K. Goyal, L. H. Hurley, K. C. Anderson, N.
C. Munshi. 2003. Telomerase inhibition and cell growth arrest by
G-quadruplex interactive agent in multiple myeloma. Mol Cancer Ther.
Shammas, M. A., H. Koley,
Goyal and C. Nikhil. Munshi. 2002. Telomerase Inhibition and
apoptotic cell growth arrest following telomestain treatment of multiple
myeloma. Blood: 100, 11 810-15.
Thungapatra, M., C. Sharma, N. Gupta, R. K. Ghosh,
A. Mukherjee, H. Koley,
G. B. Nair and A. Ghosh. 1999.
Construction of a recombinant live oral vaccine from a non-toxigenic
strain in of V.cholerae O1 serotype Inaba biotype El Tor and assessment
of its reactogenicity and immunogenicity in the rabbit model. Immunology
Letter.68: 219 -227.
Koley, H., Rupak Mitra, Arnab Basu,
Asish K. Mukhopadhyay, P. K. Saha, B. S. Ramakrisha, Selvi Krishnan,
Yoshifumi Takeda and G. Balakrish Nair. 1999. Response of
Wild-type Mutants of Vibrio cholerae 01 possessing different
combinations of Virulence zenes in the Ligated Rabbit Ileal Loop and in
Ussing chambers: Evidence for the presence of additional secretogen. J.
Med. Microbiol. 48: 51-57.
Bhattacharya, S. K., M. K. Bhattacharya, D. Dutta,
S. Dutta, M. Deb, A. Deb, A. G. Goswami, K .P. Das, H. Koley,
G. B. Nair and A. Bagati. 1997 Double-blind, randomized
clinical trial for safety and efficacy of Norfloxacin for shigellosis in
children. Acta Paediatrica.86: 319-320.
Saha, D. R., H. Koley,
A. N. Ghosh and G. B. Nair. 1997. Sequential changes in gut mucosa of rabbits
infected with Vibrio cholerae 0139 Bengal: an Ultrastructureal Study.
J. Diarrhoeal. Dis. Res.15: 59-64.
Saha, P., H. Koley and G. B. Nair.
1996 Purification and Characterization of an extra cellular
secretogenic non-membrane damaging cytotoxin produce by clinical strain
of V.cholerae Non-01. Infection Immunity.64: 3101-3108.
Saha, P., H. Koley, A. Mukherjee,
S. K. Bhattacharya, G. B. Nair, B. S. Ramakrishna, S. Krishnan, Y.
Takeda, 1996. Nontoxigenic Vibrio cholerae 01 Serotype Inaba Biotype
EIT or Associated with a Cluster of Cased of Cholera in Southern India.
Journal of Clinical Microbiology.34: 1114-1117.
Sarkar, B. L., A. K. Chakrabarty, H. Koley, M. K. Chakrabarty and S. P. Dey. 1996. Biological activity and
interaction of Vibrio cholerae bacteriopheges in rabbit ileal loop.
Indian Journal of Medical Research.104: 139-141.
Ghosh, A. R., M. Paul, H. Koley, S. K. Bhattacharya and G. B. Nair. 1996. Emergence of Shigella
species in India. Lab. Medica. International. 5: 18-24.
Ghosh, A. R., H. Koley, D. De, M. Paul,
G. B. Nair and D. Sen. 1996. ETEC associated diarrhea among
infants aged less than six months in Calcutta, India. European Journal
of Epidemiology.12: 81-84.
Koley, H., A. N. Ghosh, M. Paul,
A. R. Ghosh, P. K. Ganguly and G. B. Nair. 1995. Colonization ability and
intestinal pathology of rabbits orally fed with Vibrio cholerae 0139
Bengal. Ind. J. Med. Res.101: 57-60.
Bhattacharya, M. K., S. K. Bhattacharya, M. Paul,
D. Dutta, P. Dutta, H. Koley, D. De, A. R. Ghosh, P. Das and G. B.
Nair. 1994. Shigellosis in Calcutta during 1990-1992.
Antibiotic susceptibility pattern and clinical feature. J. Diarrhoeal
Dis. Res.12: 121-124.
Ghosh, A. R., H. Koley, D. De, S. Garg,
M. K. Bhattacharya, S. K. Bhattacharya, G. B. Nair, T. Shimada, T. Takeda
and Y. Takeda. 1994. Incidence and toxigenicity of Vibrio
cholerae in a freshwater lake during the epidemic of cholera caused by
serogroup O139 Bengal in Calcutta, India. FEMS Microbiol. Ecol. 14: