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M. J. Albert - One of the best experts on this subject based on the ideXlab platform.
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Comparison of immune responses in patients infected with Vibrio Cholerae O139 and O1.
Infection and immunity, 1997Co-Authors: Firdausi Qadri, M. J. Albert, R. B. Sack, J Hossain, C Wennerås, Kaiissar Mannoor, Yasmin Ara Begum, Golam Mohi, M. A. Salam, Ann-mari SvennerholmAbstract:Vibrio Cholerae O139 has recently emerged as the second etiologic agent of cholera in Asia. A study was carried out to evaluate the induction of specific immune responses to the organism in V. Cholerae O139-infected patients. The immune responses to V. Cholerae O139 Bengal were studied in patients by measuring antibody-secreting cells (ASC), as well as Vibriocidal and antitoxic antibodies in the circulation. These responses were compared with those in patients with V. Cholerae O1 disease. Strong immunoglobulin A (IgA) and IgM ASC responses were seen against the homologous lipopolysaccharide or serogroup of V. Cholerae. The magnitude and isotype of the responses were similar in O139- and O1-infected patients. Vibriocidal antibody responses were seen against bacteria of the homologous but not heterologous serogroup, and these responses reflect the lack of cross-protection between the infections caused by the two serogroups. The two groups of patients showed comparable cholera toxin-specific ASC responses, with the IgG isotype dominating over the IgA isotype, as well as comparable antitoxic immune responses in plasma. These results suggest that despite having a polysaccharide capsule, V. Cholerae O139 induces systemic and intestine-derived ASC responses in peripheral blood comparable to those seen in patients with V. Cholerae O1 disease.
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Rapid detection of Vibrio Cholerae O139 Bengal from stool specimens by PCR.
Journal of clinical microbiology, 1997Co-Authors: M. J. Albert, Shamsun Nahar, Firdausi Qadri, D Islam, S Falklind, Andrej WeintraubAbstract:In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio Cholerae O139 Bengal generated an amplicon from only V. Cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. Cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.
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Phenotypic and genotypic changes in Vibrio Cholerae O139 Bengal.
Journal of clinical microbiology, 1997Co-Authors: M. J. Albert, Shah M. Faruque, A. S. G. Faruque, Nurul A. Bhuiyan, Shamsun Nahar, M. Ansaruzzaman, Kaisar A. Talukder, M. RahmanAbstract:To find reasons for the recent decline of Vibrio Cholerae O139 Bengal cholera in Bangladesh, phenotypic and genotypic changes in O139 isolates obtained from patients with cholera from 1993 to 1996 were studied. The isolates were tested for the presence of ctx and tcpA genes, hemagglutinin/protease (HA/P), capsule, D-mannose-sensitive hemagglutinin (MSHA), L-fucose-sensitive hemagglutinin (FSHA), tube test (tube) and CAMP test (CAMP) hemolytic activities, resistance to 2,4-diamino-6,7-diisopropyl pteridine (O/129) and trimethoprim-sulfamethoxazole (TMP-SMX), and genotype by pulsed-field gel electrophoresis (PFGE). All isolates possessed ctx and tcpA genes, HA/P, and a capsule. Most isolates were negative for FSHA, but although the majority of the isolates were positive for MSHA, no discernible trend in the activity was found during the study period. All early isolates were CAMP hemolysin positive and resistant to the Vibriostatic compound O/129 and TMP-SMX, the two properties that could be used for the presumptive diagnosis of O139 cholera. However, subsequently, isolates that were CAMP hemolysin negative and susceptible to TMP-SMX and O/129 were increasingly encountered, with all the 1996 isolates being so, which suggested that these properties can no longer be used for the presumptive diagnosis of O139 cholera. V. Cholerae O139 isolates that were CAMP hemolysin positive and resistant to O/129 and TMP-SMX produced a disease of greater severity than that caused by the CAMP hemolysin-negative and susceptible isolates on the basis of the lengths of stay of the hospitalized patients. The study period witnessed the evolution of four different genotypes by PFGE. All of these data suggested that the V. Cholerae O139 isolates have undergone changes in some properties. However, how these changes influenced their prevalence relative to that of V. Cholerae O1 in human infection is not clear. Studies of the environmental factors will provide the key for an understanding of the relative abundance of these Vibrios.
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Simple differentiation of Vibrio Cholerae O139 from V. Cholerae O1 and non-O1, non-O139 by modified CAMP test.
Journal of clinical microbiology, 1996Co-Authors: Murad Lesmana, M. J. Albert, Decy Subekti, E Richie, P Tjaniadi, S E Walz, Carlos LebronAbstract:Strong positive CAMP reactions were demonstrated by 121 Vibrio Cholerae O139 and 504 El Tor isolates, and weak positive CAMP reactions were shown by 235 non-O1, non O139 isolates when these isolates were tested by a modified CAMP technique. Thirty-five classical biotype V. Cholerae O1 isolates included in the tests were all CAMP negative.
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Cloning and sequence of a region of Vibrio Cholerae O139 Bengal and its use in PCR-based detection.
Journal of clinical microbiology, 1996Co-Authors: S Falklind, M. J. Albert, M Stark, Mathias Uhlén, Joakim Lundeberg, A WeintraubAbstract:We isolated and characterized a Vibrio Cholerae O139 Bengal-specific DNA region by arbitrary PCR. The fragment contains open reading frames encoding two potential glycosyltransferases possibly involved in capsular polysaccharide or lipopolysaccharide biosynthesis. In order to evaluate the possibility that this region could be used for the specific detection of V. Cholerae O139 Bengal, a PCR system was established. The specificity and sensitivity of the PCR were investigated by analyzing 240 strains within the family Vibrionaceae and 178 stains of other gram-negative bacteria. All V. Cholerae O139 Bengal strains tested were positive, and none of the 384 control strains were amplified. The sensitivity of the assay was 10(2) CFU/ml.
G. Balakrish Nair - One of the best experts on this subject based on the ideXlab platform.
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Vibrio Cholerae O139 Bengal—10 years on
Reviews in Medical Microbiology, 2005Co-Authors: M. John Albert, G. Balakrish NairAbstract:A second aetiological agent of cholera, Vibrio Cholerae O139 Bengal was identified in late 1992 when it caused large outbreaks of diarrhoea in India and Bangladesh. The new strain probably arose as a result of lateral transfer of genes encoding a novel somatic antigen and a capsule from an unknown bacterium to an O1 El Tor strain with the subsequent loss of genes encoding O1 somatic antigen. O139 produces a semi-rough type colony with a truncated lipopolysaccharide which contains a unique sugar, colitose. Otherwise, O139 and O1 are strikingly similar. The diseases produced by the two serogroups are indistinguishable. There is a moderate inflammatory response in cholera, and in spite of the possession of a capsule by O139, it is no more inflammatory than O1. A number of diagnostic tests have been developed for O139 that are modelled after tests for O1 including rapid tests for field use. O139 has spread to countries of south and south-east Asia, China and Russia. Currently, cholera is caused by both these serogroups in these countries with the O1 serogroup predominant. O139 continues to cause occasional local outbreaks in India and Bangladesh. Genotyping of isolates has shown circulation of multiple clones and their derivation from multiple progenitors. Although there have been changes in antibiogram with the resistance genes being carried on a constin, the strains remain susceptible to tetracycline, a preferred antibiotic for treatment. O139 carries a number of filamentous lysogenic and lytic phages and the latter have been utilized to develop a phage typing scheme. A number of environmental variables have been linked to the occurrence of cholera and lytic phages may determine the course of epidemics. Although the capsule confers serum resistance, Vibriocidal antibody assay has been developed for O139. However, unlike in O1 cholera, serum Vibriocidal antibody does not seem to correlate with protection against O139 infection. Promising O139 vaccines have been developed or are in the pipeline. It is too early to predict whether O139 will become the causative agent of 'the eighth pandemic of cholera'; it will require many years of monitoring and reporting from regions prone to cholera to find the answer.
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Emergence and evolution of Vibrio Cholerae O139
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Shah M. Faruque, R Bradley Sack, David A. Sack, Rita R. Colwell, Yoshifumi Takeda, G. Balakrish NairAbstract:The emergence of Vibrio Cholerae O139 Bengal during 1992–1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. Cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of either of the two serogroups that was associated with temporal genetic and phenotypic changes sustained by the strains. Since the initial emergence of the O139 Vibrios, new variants of the pathogen derived from multiple progenitors have been isolated and characterized. The clinical and epidemiological characteristics of these strains have been studied. Rapid genetic reassortment in O139 strains appears to be a response to the changing epidemiology of V. Cholerae O1 and also a strategy for persistence in competition with strains of the O1 serogroup. The emergence of V. Cholerae O139 has provided a unique opportunity to witness genetic changes in V. Cholerae that may be associated with displacement of an existing serogroup by a newly emerging one and, thus, provide new insights into the epidemiology of cholera. The genetic changes and natural selection involving both environmental and host factors are likely to influence profoundly the genetics, epidemiology, and evolution of toxigenic V. Cholerae, not only in the Ganges Delta region of India and Bangladesh, but also in other areas of endemic and epidemic cholera.
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Reemergence of epidemic Vibrio Cholerae O139, Bangladesh
Emerging infectious diseases, 2003Co-Authors: Shah M. Faruque, Nityananda Chowdhury, M. Kamruzzaman, Q. Shafi Ahmad, A. S. G. Faruque, M. Abdus Salam, T. Ramamurthy, G. Balakrish Nair, Andrej Weintraub, David A. SackAbstract:During March and April 2002, a resurgence of Vibrio Cholerae O139 occurred in Dhaka and adjoining areas of Bangladesh with an estimated 30,000 cases of cholera. Patients infected with O139 strains were much older than those infected with O1 strains (p
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Genomic diversity among Vibrio Cholerae O139 strains isolated in Bangladesh and India between 1992 and 1998
FEMS microbiology letters, 2000Co-Authors: Shah M. Faruque, R Bradley Sack, Yoshifumi Takeda, Rupak K. Bhadra, Manujendra N. Saha, Asadulghani, Prasanta K. Bag, S. K. Bhattacharya, G. Balakrish NairAbstract:In order to assess the extent of genomic diversity among Vibrio Cholerae O139 strains, restriction fragment length polymorphisms in two genetic loci, rrn and ctx, were studied. Analysis of 144 strains isolated from different regions of Bangladesh and India between 1992 and 1998 revealed the presence of at least six distinct ribotypes (B-I through B-VI) of which three were new ribotypes, and one of these was represented by a nontoxigenic O139 strain. Strains of ribotypes B-I through B-V shared 11 different CTX genotypes (A through K). Antimicrobial resistance patterns of the strains varied independently of their ribotypes and CTX genotypes. Results of this study suggest that V. Cholerae O139 is undergoing rapid genetic changes leading to the origination of new variants, and temporal changes in antimicrobial resistance patterns may be contributing to the selection of different variants.
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Development and Evaluation of a Phage Typing Scheme for Vibrio Cholerae O139
Journal of clinical microbiology, 2000Co-Authors: Arunaloke Chakrabarti, G. Balakrish Nair, S. K. Bhattacharya, Arghyaprasun Ghosh, Swapan Kumar Niyogi, B. L. SarkarAbstract:The scenario of cholera that existed previously changed in 1992 and 1993 with the emergence of toxigenic Vibrio Cholerae O139 in India. The genesis of the new serogroup formed the impetus to search for O139 phages in and around the country. A total of five newly isolated phages lytic to V. Cholerae O139 strains were used for the development of this phage typing scheme. These phages differed from each other and also differed from the existing O1 phages in their lytic patterns, morphologies, restriction endonuclease digestion profiles, and immunological criteria. With this scheme, 500 V. Cholerae O139 strains were evaluated for their phage types, and almost all strains were found to be typeable. The strains clustered into 10 different phage types, of which type 1 (38.2%) was the dominant type, followed by type 2 (22.4%) and type 3 (18%). Additionally, a comparative study of phage types in 1993 and 1994 versus those from 1996 to 1998 for O139 strains showed a higher percentage of phage type 1 (40.5%), followed by type 3 (18.8%) during the period between 1993 and 1994, whereas phage type 2 (32.1%) was the next major type during the period from 1996 to 1998. This scheme comprising five newly isolated phages would be another useful tool in the study of the epidemiology of cholera caused by V. Cholerae O139.
Yoshifumi Takeda - One of the best experts on this subject based on the ideXlab platform.
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Emergence and evolution of Vibrio Cholerae O139
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Shah M. Faruque, R Bradley Sack, David A. Sack, Rita R. Colwell, Yoshifumi Takeda, G. Balakrish NairAbstract:The emergence of Vibrio Cholerae O139 Bengal during 1992–1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. Cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of either of the two serogroups that was associated with temporal genetic and phenotypic changes sustained by the strains. Since the initial emergence of the O139 Vibrios, new variants of the pathogen derived from multiple progenitors have been isolated and characterized. The clinical and epidemiological characteristics of these strains have been studied. Rapid genetic reassortment in O139 strains appears to be a response to the changing epidemiology of V. Cholerae O1 and also a strategy for persistence in competition with strains of the O1 serogroup. The emergence of V. Cholerae O139 has provided a unique opportunity to witness genetic changes in V. Cholerae that may be associated with displacement of an existing serogroup by a newly emerging one and, thus, provide new insights into the epidemiology of cholera. The genetic changes and natural selection involving both environmental and host factors are likely to influence profoundly the genetics, epidemiology, and evolution of toxigenic V. Cholerae, not only in the Ganges Delta region of India and Bangladesh, but also in other areas of endemic and epidemic cholera.
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Vibrio Cholerae O139 Bengal: odyssey of a fortuitous variant.
Microbes and infection, 2003Co-Authors: Thandavarayan Ramamurthy, Shinji Yamasaki, Yoshifumi Takeda, G B NairAbstract:Vibrio Cholerae O139, the new serogroup associated with epidemic cholera, came into being in the second half of the year 1992 in an explosive fashion and was responsible for several outbreaks in India and other neighbouring countries. This was an unprecedented event in the history of cholera and the genesis of the O139 serogroup was, at that time, thought to be the beginning of the next or the eighth pandemic of cholera. However, with the passage of time, the O1 serogroup of the El Tor biotype again reappeared and displaced the O139 serogroup on the Indian subcontinent, and there was a feeling among cholera workers that the appearance of this new serogroup may have been a one-time event. The resurgence of the O139 serogroup in September 1996 in Calcutta and the coexistence of both the O1 and O139 serogroups in much of the cholera endemic areas in India and elsewhere, suggested that the O139 serogroup has come to stay and is a permanent entity to contend with in the coming years. During the past 10 years, intensive work on all aspects of the O139 serogroup was carried out by cholera researchers around the world. The salient findings on this serogroup over the past 10 years pertinent to its prevalence, clinico-epidemiological features, virulence-associated genes, rapid screening and identification, molecular epidemiology, and vaccine developments have been highlighted.
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Genomic diversity among Vibrio Cholerae O139 strains isolated in Bangladesh and India between 1992 and 1998
FEMS microbiology letters, 2000Co-Authors: Shah M. Faruque, R Bradley Sack, Yoshifumi Takeda, Rupak K. Bhadra, Manujendra N. Saha, Asadulghani, Prasanta K. Bag, S. K. Bhattacharya, G. Balakrish NairAbstract:In order to assess the extent of genomic diversity among Vibrio Cholerae O139 strains, restriction fragment length polymorphisms in two genetic loci, rrn and ctx, were studied. Analysis of 144 strains isolated from different regions of Bangladesh and India between 1992 and 1998 revealed the presence of at least six distinct ribotypes (B-I through B-VI) of which three were new ribotypes, and one of these was represented by a nontoxigenic O139 strain. Strains of ribotypes B-I through B-V shared 11 different CTX genotypes (A through K). Antimicrobial resistance patterns of the strains varied independently of their ribotypes and CTX genotypes. Results of this study suggest that V. Cholerae O139 is undergoing rapid genetic changes leading to the origination of new variants, and temporal changes in antimicrobial resistance patterns may be contributing to the selection of different variants.
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Vibrio Cholerae O139 in Calcutta, 1992-1998: incidence, antibiograms, and genotypes.
Emerging infectious diseases, 2000Co-Authors: Arnab Basu, Sujit K. Bhattacharya, Pallavi Garg, Simanti Datta, Soumen Chakraborty, T. Bhattacharya, Asis Khan, S. Ramamurthy, Shinji Yamasaki, Yoshifumi TakedaAbstract:We report results of surveillance for cholera caused by Vibrio Cholerae O139 from September 1992, when it was first identified, to December 1998. V. Cholerae O139 dominated as the causative agent of cholera in Calcutta during 1992-93 and 1996-97, while the O1 strains dominated during the rest of the period. Dramatic shifts in patterns of resistance to cotrimoxazole, neomycin, and streptomycin were observed. Molecular epidemiologic studies showed clonal diversity among the O139 strains and continuous emergence of new epidemic clones, reflected by changes in the structure, organization, and location of the CTX prophages in the V. Cholerae O139 chromosome.
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Molecular Epidemiology of Reemergent Vibrio Cholerae O139 Bengal in India
Journal of clinical microbiology, 1998Co-Authors: Asish K. Mukhopadhyay, Yoshifumi Takeda, Arnab Basu, Pallavi Garg, P. K. Bag, Amit Ghosh, G. Balakrish NairAbstract:We report the prevalence of the O139 serogroup in Calcutta, India, after its reemergence in August 1996 and the spread of the reemerged clone to other parts of the country by using previously established molecular markers. Phenotypically, the reemerged Vibrio Cholerae O139 displayed a difference compared to those that appeared in late 1992 and 1993 in that the current O139 strains are sensitive to co-trimoxazole. Ribotyping with the enzyme BglI produced two rRNA restriction patterns in the O139 strains isolated after August 1996, and these patterns were identical to those exhibited by strains of O139 isolated in 1992. Three clones of V. Cholerae O139 are currently prevailing in the country, with strains exhibiting three bands after HindIII digestion and hybridization with a ctxA probe being dominant. The reemergence of V. Cholerae O139 in Calcutta after a 32-month quiescent period reestablishes the O139 serogroup as an entity which is likely to play a crucial role in the temporal antigenic variations among the serogroups of V. Cholerae causing cholera.
Toshio Shimada - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Vibrio Cholerae O139 isolated in Taiwan
Food Microbiology, 2002Co-Authors: Hin-chung Wong, Ding-ping Liu, Shu-hui Liu, Yu-chun Chung, Toshio ShimadaAbstract:Abstract Vibrio Cholerae O139 Bengal is the second aetiologic agent of the cholera epidemic that emerged in late 1992 in India which has subsequently spread to other nations. A few sporadic cases of V. Cholerae O139 infection have been reported in Taiwan since 1997. The V. Cholerae O139 strains isolated from clinical and environmental sources in Taiwan were characterized based on subspecies molecular typing, toxin production, and susceptibility to antibiotics and environmental stresses, and were compared to several O1 and other non-O1/non-O139 strains. Typing by pulsed-field gel electrophoresis revealed that the domestic O139 strains were identical to three of the four Japanese strains. Most of these domestic O139 strains were alpha-haemolytic and produced highly variable amounts of cholera toxin. The presence of cholera toxin gene was confirmed in all of these domestic strains by polymerase chain reaction. Meanwhile, most of the domestic O139 strains were resistant to nitrofurantoin, streptomycin, furazolidone and trimethoprim–sulfamethoxazole, while the O1 strains were not. Susceptibility of selected O139 strains to temperature stresses at 55°C and −20°C, acid treatment at pH 3·0, and N-alkyl dimethyl benzyl ammonium treatment did not differ significantly from other strains examined. Accordingly, these Taiwanese O139 strains were genetically close to the Japanese strains and also shared some common biological traits.
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Phage specific for Vibrio Cholerae O139 Bengal.
Journal of clinical microbiology, 1996Co-Authors: M. John Albert, Andrej Weintraub, Nurul A. Bhuiyan, A. Rahman, A. N. Ghosh, Kjell Hultenby, Shamsun Nahar, A. K. M. G. Kibriya, M. Ansaruzzaman, Toshio ShimadaAbstract:From the stool of a Vibrio Cholerae O139 Bengal-infected patient, a phage that specifically lysed capsulated V. Cholerae O139 strains only was isolated. The phage is useful for the confirmatory diagnosis of V. Cholerae O139 infection and for the differentiation of variants that lack the capsule.
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Evaluation of DNA probes for specific detection of Vibrio Cholerae O139 Bengal.
Journal of clinical microbiology, 1995Co-Authors: G B Nair, Toshio Shimada, Thandavarayan Ramamurthy, P. K. Bag, Tae Takeda, Shingo Yamamoto, Hisao Kurazono, Yoshifumi TakedaAbstract:Two DNA probes, 2R1 and 2R3, prepared from a region in the chromosome specific for the lipopolysaccharide O side chains of Vibrio Cholerae O139 (M.K. Waldor and J.J. Mekalanos, Lancet 343:1366, 1994) were examined for their specificity and sensitivity. Both probes did not hybridize with any strain of V. Cholerae belonging to serogroups other than O139 and to any of the other species examined belonging to the family Vibrionaceae. Among the 126 strains of V. Cholerae O139 examined, probe 2R1 hybridized with 125 strains while probe 2R3 hybridized with all 126 strains. Both probes were found to be highly specific and sensitive and can be used for the specific identification of V. Cholerae O139.
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Characterization of Aeromonas trota strains that cross-react with Vibrio Cholerae O139 Bengal.
Journal of clinical microbiology, 1995Co-Authors: M. J. Albert, Nurul A. Bhuiyan, A. Rahman, Shamsun Nahar, M. Ansaruzzaman, Toshio Shimada, Firdausi Qadri, Mohammad Sirajul IslamAbstract:It has previously been shown that Vibrio Cholerae O139 Bengal shares antigens with V. Cholerae serogroups O22 and O155. We detected six surface water isolates of Aeromonas trota that agglutinated in polyclonal antisera to V. Cholerae O139 and V. Cholerae O22 but not in antiserum to V. Cholerae O155. On the basis of agglutinin-absorption studies, the antigenic relationship between the cross-reacting bacteria were found to be in an a,b-a,c fashion, where a is the common antigenic epitope and b and c are unique epitopes. The antigen sharing between A. trota strains and V. Cholerae O139 was confirmed in immunoblot studies. However, A. trota strains did not react with two monoclonal antibodies specific for V. Cholerae O139 and, consequently, tested negative in the Bengal SMART rapid diagnostic test for V. Cholerae O139 which uses one of the monoclonal antibodies. A polyclonal antiserum to a cross-reacting A. trota strain cross-protected infant mice against cholera on challenge with virulent V. Cholerae O139. All A. trota strains were cytotoxic for HeLa cells, positive for adherence to HEp-2 cells, and weakly invasive for HEp-2 cells; one strain was heat-stable toxin positive in the suckling mouse assay; however, all strains were negative for cholera toxin-like enterotoxin. Studies on bacteria that share somatic antigen with V. Cholerae O139 may shed further light on the genesis of V. Cholerae O139.
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The first report of traveler's diarrhea associated with a newly described toxigenic Vibrio Cholerae O139 strain in Japan
Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases, 1994Co-Authors: Takayuki Kurazono, Fumiya Yamada, Masanori Yamaguchi, Yoko Ohzeki, Yusuke Okuyama, Kenichiro Itoh, Toshio ShimadaAbstract:A newly described Vibrio Cholerae O139 was isolated from a patient who had traveled in India on April 1993. The patient experienced 5 to 6 watery diarrhea per day after he returned to Japan. The isolated strain registered as K111 did not agglutinate with O1-O138 antiserum and agglutinated with O139 antiserum. This strain resembled V. Cholerae O1 strain in biochemical characters and had ctx and zot, although was resistant to the Vibrio static agent O/129. This is the first report of cholera-like illness by the newly described toxigenic V. Cholerae O139 strain in Japan.
G B Nair - One of the best experts on this subject based on the ideXlab platform.
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changing genotypes of cholera toxin ct of Vibrio Cholerae O139 in bangladesh and description of three new ct genotypes
Fems Immunology and Medical Microbiology, 2009Co-Authors: N A Bhuiyan, Thandavarayan Ramamurthy, Munirul Alam, Suraia Nusrin, Masatomo Morita, Haruo Watanabe, Alejandro Cravioto, G B NairAbstract:We determined the genotype of cholera toxin by amplifying and sequencing the B-subunit in a sequential collection of 90 strains of Vibrio Cholerae O139 isolated over the past 13 years since its first description in 1992. Representative strains isolated during 1993–1997 harboured ctxB of El Tor type (genotype 3). Twenty-six strains isolated during 1999, 2001, 2005 and three strains isolated in 1998, 2000 and 2002 were identified to belong to new ctxB genotypes 4 and 5, respectively. Genotype 5 was similar to genotype 1 except at position 28 (D→A). The genotype 6 was similar to genotype 4 except at position 34 (H→P). The implication of switch in terms of function of the toxin and its impact on human disease is unclear. How this change has influenced their prevalence relative to that of V. Cholerae O1 in human infection is also not clear. The other common virulence gene clusters including the Vibrio pathogenicity island-1, Vibrio seventh pandemic island (VSP)-I and VSP-II of V. Cholerae O139 did not show any remarkable difference from that of the O1 El Tor strains. Overall, the majority of the O139 strains tested in this study were similar to the El Tor strains but had altered ctxB genotype. This change and the impact that it causes to the epidemiology of cholera caused by O139 should be closely monitored.
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Vibrio Cholerae O139 Bengal: odyssey of a fortuitous variant.
Microbes and infection, 2003Co-Authors: Thandavarayan Ramamurthy, Shinji Yamasaki, Yoshifumi Takeda, G B NairAbstract:Vibrio Cholerae O139, the new serogroup associated with epidemic cholera, came into being in the second half of the year 1992 in an explosive fashion and was responsible for several outbreaks in India and other neighbouring countries. This was an unprecedented event in the history of cholera and the genesis of the O139 serogroup was, at that time, thought to be the beginning of the next or the eighth pandemic of cholera. However, with the passage of time, the O1 serogroup of the El Tor biotype again reappeared and displaced the O139 serogroup on the Indian subcontinent, and there was a feeling among cholera workers that the appearance of this new serogroup may have been a one-time event. The resurgence of the O139 serogroup in September 1996 in Calcutta and the coexistence of both the O1 and O139 serogroups in much of the cholera endemic areas in India and elsewhere, suggested that the O139 serogroup has come to stay and is a permanent entity to contend with in the coming years. During the past 10 years, intensive work on all aspects of the O139 serogroup was carried out by cholera researchers around the world. The salient findings on this serogroup over the past 10 years pertinent to its prevalence, clinico-epidemiological features, virulence-associated genes, rapid screening and identification, molecular epidemiology, and vaccine developments have been highlighted.
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Sequential changes in gut mucosa of rabbits infected with Vibrio Cholerae O139 Bengal: an ultrastructural study.
Journal of diarrhoeal diseases research, 1997Co-Authors: Koley H, G B NairAbstract:Adhesion and subsequent colonisation are important events in the infection by Vibrio Cholerae O139 Bengal. To determine in details the pathological changes in the gut mucosa, an epidemic strain of O139 Bengal was inoculated in a rabbit ileal loop model. Electron microscopic studies were done at different time intervals after inoculation of the strain to see the histological changes at the ultrastructural level. From 10 hours onwards, cellular invasive processes with presence of bacteria in the lamina propria and other associated inflammatory changes were revealed.
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Unique organization of the CTX genetic element in Vibrio Cholerae O139 strains which reemerged in Calcutta, India, in September 1996.
Journal of clinical microbiology, 1997Co-Authors: Charu Sharma, Asish K. Mukhopadhyay, G B Nair, Arnab Basu, Sudeshna Kar, Sankar Maiti, Indira Basu, R Mukhopadhyaya, B. Das, R. K. GhoshAbstract:We studied the restriction fragment length polymorphism of the rRNA gene and CTX genetic element in Vibrio Cholerae O139 Bengal, which resurged in Calcutta in September 1996 after a gap of 32 months. While the strains from this resurgence were indistinguishable from the earlier strains by ribotyping, the structure of the CTX genetic element present in the current O139 strains was found to be unconventional.
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Evaluation of DNA probes for specific detection of Vibrio Cholerae O139 Bengal.
Journal of clinical microbiology, 1995Co-Authors: G B Nair, Toshio Shimada, Thandavarayan Ramamurthy, P. K. Bag, Tae Takeda, Shingo Yamamoto, Hisao Kurazono, Yoshifumi TakedaAbstract:Two DNA probes, 2R1 and 2R3, prepared from a region in the chromosome specific for the lipopolysaccharide O side chains of Vibrio Cholerae O139 (M.K. Waldor and J.J. Mekalanos, Lancet 343:1366, 1994) were examined for their specificity and sensitivity. Both probes did not hybridize with any strain of V. Cholerae belonging to serogroups other than O139 and to any of the other species examined belonging to the family Vibrionaceae. Among the 126 strains of V. Cholerae O139 examined, probe 2R1 hybridized with 125 strains while probe 2R3 hybridized with all 126 strains. Both probes were found to be highly specific and sensitive and can be used for the specific identification of V. Cholerae O139.
