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1
Kaper, J. B., J. G. Morris, and M. M. Levine. "Cholera." Clinical Microbiology Reviews 8, no. 1 (January 1995): 48–86. http://dx.doi.org/10.1128/cmr.8.1.48.
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Despite more than a century of study, cholera still presents challenges and surprises to us. Throughout most of the 20th century, cholera was caused by Vibrio cholerae of the O1 serogroup and the disease was largely confined to Asia and Africa. However, the last decade of the 20th century has witnessed two major developments in the history of this disease. In 1991, a massive outbreak of cholera started in South America, the one continent previously untouched by cholera in this century. In 1992, an apparently new pandemic caused by a previously unknown serogroup of V. cholerae (O139) began in India and Bangladesh. The O139 epidemic has been occurring in populations assumed to be largely immune to V. cholerae O1 and has rapidly spread to many countries including the United States. In this review, we discuss all aspects of cholera, including the clinical microbiology, epidemiology, pathogenesis, and clinical features of the disease. Special attention will be paid to the extraordinary advances that have been made in recent years in unravelling the molecular pathogenesis of this infection and in the development of new generations of vaccines to prevent it.
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Larionova, L. V., R. V. Pisanov, D. I. Simakova, A. N. Narkevich, and I. V. Arkhangel’skaya. "Polimeric Immunoglobulin Diagnosticum for Detection of Cholera Toxin and Assessing the Level of Its Production by Vibrios." Problems of Particularly Dangerous Infections, no. 4 (January 26, 2022): 84–89. http://dx.doi.org/10.21055/0370-1069-2021-4-84-89.
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A marker of the epidemic significance of Vibrio cholerae is their toxigenicity. Therefore, much attention is currently paid to the creation of diagnostic preparations for the detection of cholera toxin and assessment of the level of its production. The volumetric immunosuspension agglomeration reaction, carried out with the help of latex diagnosticums, is an analogue of the indirect hemagglutination reaction, an affordable and technically simple method, since it does not require special equipment and can be used when conducting research in the field. The aim of the study was to design a polymeric immunoglobulin diagnosticum for determining cholera toxin and the level of its production by vibrio strains. Materials and methods. Cholera toxin was obtained from the producer strain Vibrio cholerae Classical 569 B. Rabbit serum to the toxin was obtained according to the method selected by the authors. A polymeric diagnostic immunoglobulin antitoxic drug was obtained through sensitizing immunoglobulins from cholera antitoxic rabbit serum on the surface of polyacrolein microspheres with a size of (1±0.1) μm. Results and discussion. The analytical sensitivity of the developed diagnostic preparation with control cholera toxin is 100 ng/ml. It detects cholera toxin in toxigenic strains of Vibrio cholerae in a titer of 1:16 – 1:512, gives negative results with non-toxigenic strains of V. cholerae O1, V. Cholerae nonO1/nonO139, with samples of heterologous cultures, LPS preparations, liquid nutrient medium used for the cultivation of V. cholerae. Thus, a polymeric immunoglobulin diagnosticum has been constructed to detect and quantify the production of cholera toxin by vibrio strains, and its analytical sensitivity and specificity have been established.
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Kitaoka, Maya, Sarah T. Miyata, Daniel Unterweger, and Stefan Pukatzki. "Antibiotic resistance mechanisms of Vibrio cholerae." Journal of Medical Microbiology 60, no. 4 (April 1, 2011): 397–407. http://dx.doi.org/10.1099/jmm.0.023051-0.
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As the causative agent of cholera, the bacterium Vibrio cholerae represents an enormous public health burden, especially in developing countries around the world. Cholera is a self-limiting illness; however, antibiotics are commonly administered as part of the treatment regimen. Here we review the initial identification and subsequent evolution of antibiotic-resistant strains of V. cholerae. Antibiotic resistance mechanisms, including efflux pumps, spontaneous chromosomal mutation, conjugative plasmids, SXT elements and integrons, are also discussed. Numerous multidrug-resistant strains of V. cholerae have been isolated from both clinical and environmental settings, indicating that antibiotic use has to be restricted and alternative methods for treating cholera have to be implemented.
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Chattaway, Marie Anne, Abdul Kamara, Fay Rhodes, Konneh Kaffeta, Amara Jambai, Wondimagegnehu Alemu, Mohammed Sirajul Islam, et al. "Establishing an enteric bacteria reference laboratory in Sierra Leone." Journal of Infection in Developing Countries 8, no. 07 (June 9, 2014): 933–41. http://dx.doi.org/10.3855/jidc.5074.
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In 2012, Sierra Leone experienced its worst cholera outbreak in over 15 years affecting 12 of the country’s 13 districts. With limited diagnostic capability, particularly in bacterial culture, the cholera outbreak was initially confirmed by microbiological testing of clinical specimens outside of Sierra Leone. During 2012 – 2013, in direct response to the lack of diagnostic microbiology facilities, and to assist in investigating and monitoring the cholera outbreak, diagnostic and reference services were established in Sierra Leone at the Central Public Health Reference Laboratory focusing specifically on isolating and identifying Vibrio cholerae and other enteric bacterial pathogens. Sierra Leone is now capable of confirming cholera cases by reference laboratory testing.
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LaRocque, Regina C., Bryan Krastins, Jason B. Harris, Lauren M. Lebrun, Kenneth C. Parker, Michael Chase, Edward T. Ryan, Firdausi Qadri, David Sarracino, and Stephen B. Calderwood. "Proteomic Analysis of Vibrio cholerae in Human Stool." Infection and Immunity 76, no. 9 (June 30, 2008): 4145–51. http://dx.doi.org/10.1128/iai.00585-08.
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ABSTRACT An effective vaccine for Vibrio cholerae is not yet available for use in the developing world, where the burden of cholera disease is highest. Characterizing the proteins that are expressed by V. cholerae in the human host environment may provide insight into the pathogenesis of cholera and assist with the development of an improved vaccine. We analyzed the V. cholerae proteins present in the stools of 32 patients with clinical cholera. The V. cholerae outer membrane porin, OmpU, was identified in all of the human stool samples, and many V. cholerae proteins were repeatedly identified in separate patient samples. The majority of V. cholerae proteins identified in human stool are involved in protein synthesis and energy metabolism. A number of proteins involved in the pathogenesis of cholera, including the A and B subunits of cholera toxin and the toxin-coregulated pilus, were identified in human stool. In a subset of stool specimens, we also assessed which in vivo expressed V. cholerae proteins were recognized uniquely by convalescent-phase as opposed to acute-phase serum from cholera patients. We identified a number of these in vivo expressed proteins as immunogenic during human infection. To our knowledge, this is the first characterization of the proteome of a pathogenic bacteria recovered from a natural host.
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Nalin, D. R. "Cholera or Choleric?" Clinical Infectious Diseases 46, no. 1 (January 1, 2008): 150. http://dx.doi.org/10.1086/524088.
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Khan, Ashraful Islam, Md Mahbubur Rashid, Md Taufiqul Islam, Mokibul Hassan Afrad, M. Salimuzzaman, Sonia Tara Hegde, Md Mazharul I. Zion, et al. "Epidemiology of Cholera in Bangladesh: Findings From Nationwide Hospital-based Surveillance, 2014–2018." Clinical Infectious Diseases 71, no. 7 (December 31, 2019): 1635–42. http://dx.doi.org/10.1093/cid/ciz1075.
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Abstract Background Despite advances in prevention, detection, and treatment, cholera remains a major public health problem in Bangladesh and little is known about cholera outside of limited historical sentinel surveillance sites. In Bangladesh, a comprehensive national cholera control plan is essential, although national data are needed to better understand the magnitude and geographic distribution of cholera. Methods We conducted systematic hospital-based cholera surveillance among diarrhea patients in 22 sites throughout Bangladesh from 2014 to 2018. Stool specimens were collected and tested for Vibrio cholerae by microbiological culture. Participants’ socioeconomic status and clinical, sanitation, and food history were recorded. We used generalized estimating equations to identify the factors associated with cholera among diarrhea patients. Results Among 26 221 diarrhea patients enrolled, 6.2% (n = 1604) cases were V. cholerae O1. The proportion of diarrhea patients positive for cholera in children <5 years was 2.1% and in patients ≥5 years was 9.5%. The proportion of cholera in Dhaka and Chittagong Division was consistently high. We observed biannual seasonal peaks (pre- and postmonsoon) for cholera across the country, with higher cholera positivity during the postmonsoon in western regions and during the pre–monsoon season in eastern regions. Cholera risk increased with age, occupation, and recent history of diarrhea among household members. Conclusions Cholera occurs throughout a large part of Bangladesh. Cholera-prone areas should be prioritized to control the disease by implementation of targeted interventions. These findings can help strengthen the cholera-control program and serve as the basis for future studies for tracking the impact of cholera-control interventions in Bangladesh.
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Agustanty, Adelia, and Andre Budi. "POLA RESISTENCY OF VIBRIO CHOLERAE BACTERIA TO THE ANTIBIOTIC CIPROFLOXACIN AND TETRACYCLINE." Journal Health & Science : Gorontalo Journal Health and Science Community 5, no. 3 (April 8, 2022): 73–78. http://dx.doi.org/10.35971/gojhes.v5i3.13611.
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Abstrak Diare merupakan kegiatan defekasi (buang air besar) yang biasanya berbentuk 1/2 padat atau cenderung lebih cair yang berlangsung lebih dari tiga kali sehari atau dalam waktu yang singkat, vibrio cholera adalah salah satu penyebabnya, bakteri ini merupakan bakteri gram negatif yang berbentuk koma galibnya masa inkubasi bakteri ini adalah 12-72 jam. Bakteri vibrio cholerae menyulut penyakit bakteri. Jenis penelitian ini adalah penelitian laboratorium eksperimental dengan menggunakan arsip sampel bakteri vibrio cholerae dan cakram antibiotik ciprofloxacin. Tujuan penelitian untuk mengetahui pola resistensi antibiotik ciprofloxacin terhadap bakteri vibrio cholerae. Populasi yang digunakan adalah isolate murni bakteri Vibrio cholera dan sampel yang digunakan adalah sediaan cakram dari antibiotik Ciprofloxacin dan Tetracycline. Nilai rata-rata (mm) selama 24 jam ciprofloxcacin : 37.425 , tetracycline : 24,175 Nilai rata-rata (mm) selam 48 jam ciprofloxacin : 29,875 tetracycline : 22,95 Berdasarkan hasil data dan gambar penelitian dapat di simpulkan bahwa diameter zona hambat atau zona bening dari biakan bakteri vibrio cholera yang terdapat dalam cawan petri dengan media MHA serta cakram antibiotik ciprofloxacin dan tetracycline menunjukkan bahwa bakteri uji masih sensitive terhadap kedua antibiotik uji yang dimana nilai rata-rata nya adalah 29,875 dan 22,95 mm dimana menurut standart CLSI (Clinical Laboratory Standards Institute), diameter zona hambat bakteri ≥ 17 mm, kategori intermediet apabila diameter zona hambat bakteri 14-16 mm, dan kategori resisten apabila diameter zona hambat bakteri yaitu ≤ 13mm. Kesimpulan bahwa biakan bakteri vibrio choleramasih sensitive terhadap kedua antibiotic ciprofloxacin dan tetracycline. Kata Kunci : Ciprofloxacin; Cholera; Diare; Tetracycline; Vibrio Cholerae. Abstract Diarrhea is a defecation activity (defecation) which is usually in the form of 1/2 solid or tends to be more liquid (watery) which lasts more than three times a day or in a short time, Vibrio cholera is one of the causes, this bacterium is a gram-negative bacterium that causes diarrhea. In the form of a comma, the incubation period for this bacterium is 12-72 hours. Vibrio cholerae bacteria cause bacterial disease. This type of research is an experimental laboratory study using archived samples of Vibrio cholerae bacteria and ciprofloxacin antibiotic discs. This study aims to determine the pattern of resistance to ciprofloxacin antibiotics against Vibrio cholerae bacteria. The population that will be used is pure isolate of Vibrio cholera bacteria and the sample used is disc preparation of the antibiotics Ciprofloxacin and Tetracycline. Average value (mm) for 24 hours ciprofloxcacin: 37.425, tetracycline: 24.175 Average value (mm) for 48 hours ciprofloxacin : 29.875 tetracycline : 22.95 Based on the results of the data and research images it can be concluded that the diameter of the inhibition zone or clear zone of the Vibrio cholera bacteria culture contained in petri dishes with MHA media and ciprofloxacin and tetracycline antibiotic discs showed that the test bacteria were still sensitive to the two test antibiotics where the average value was 29.875 and 22.95 mm where according to the CLSI (Clinical Laboratory Standards Institute) standard, the diameter of the bacterial inhibition zone was 17 mm, the intermediate category if the diameter of the bacterial inhibition zone was 14-16 mm, and the category of intermediate was 14-16 mm. resistant if the diameter of the bacterial inhibition zone is 13 mm. The conclusion is that the vibrio cholera bacteria culture is still sensitive to both ciprofloxacin and tetracycline antibiotics. Keywords: Ciprofloxacin ; Cholerae; Diarrhea ; Tetracycline ; Vibrio Cholerae.
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Kumar, P., M. Jain, A. K. Goel, S. Bhadauria, S. K. Sharma, D. V. Kamboj, L. Singh, T. Ramamurthy, and G. B. Nair. "A large cholera outbreak due to a new cholera toxin variant of the Vibrio cholerae O1 El Tor biotype in Orissa, Eastern India." Journal of Medical Microbiology 58, no. 2 (February 1, 2009): 234–38. http://dx.doi.org/10.1099/jmm.0.002089-0.
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A total of 32 Vibrio cholerae isolates were collected during a recent large cholera outbreak in Eastern India. Biochemical and serological studies revealed that all of the isolates belonged to serogroup O1, biotype El Tor, serotype Ogawa. Two multiplex PCR assays confirmed the presence of various toxigenic and pathogenic genes – ace, ctxAB, hlyA, ompU, ompW, rfbO1, rtx, tcp, toxR and zot – in all of the isolates. Sequencing of the ctxB gene from the isolates revealed a novel mutation in the gene. Sequencing also confirmed the presence of altered cholera toxin B of the classical biotype in all of the El Tor isolates, suggesting infection of isolates by classical CTXΦ. The molecular diversity of V. cholerae isolates studied by enterobacterial repetitive intergenic consensus sequence PCR, BOX-PCR and randomly amplified polymorphic DNA analysis uniformly showed the clonal relationship among the outbreak V. cholerae O1 isolates. The results of this study suggest that cholera-causing V. cholerae strains are constantly evolving in epidemic areas, highlighting the potential of the emergence of more virulent strains.
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Saidi, Suleiman M., Nityananda Chowdhury, Sharda P. Awasthi, Masahiro Asakura, Atsushi Hinenoya, Yoshio Iijima, and Shinji Yamasaki. "Prevalence of Vibrio cholerae O1 El Tor variant in a cholera-endemic zone of Kenya." Journal of Medical Microbiology 63, no. 3 (March 1, 2014): 415–20. http://dx.doi.org/10.1099/jmm.0.068999-0.
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Since 2007, Kenya has experienced an increase in cholera outbreaks characterized by a high fatality rate. In this study, we characterized 81 Vibrio cholerae isolates from diarrhoeal stool samples in Nyanza, a cholera-endemic lake region of Kenya, for virulence properties, clonality and antibiotic susceptibility. Eighty of these isolates were V. cholerae O1 El Tor variants carrying the classical ctxB gene sequence, while one isolate was V. cholerae non-O1/O139. All of the El Tor variants were of clonal origin, as revealed by PFGE, and were susceptible to ampicillin, tetracycline, ciprofloxacin, fosfomycin, kanamycin and norfloxacin. However, the isolates showed resistance to sulfamethoxazole/trimethoprim and streptomycin, and intermediate resistance to nalidixic acid, chloramphenicol and imipenem. The non-O1/O139 isolate carried the cholix toxin II gene (chxA II) and was susceptible to all antimicrobials tested except ampicillin. We propose that an El Tor variant clone caused the Nyanza cholera outbreak of 2007–2008.
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Ryan, Edward T., Daniel T. Leung, Owen Jensen, Ana A. Weil, Taufiqur Rahman Bhuiyan, Ashraful Islam Khan, Fahima Chowdhury, et al. "Systemic, Mucosal, and Memory Immune Responses following Cholera." Tropical Medicine and Infectious Disease 6, no. 4 (October 27, 2021): 192. http://dx.doi.org/10.3390/tropicalmed6040192.
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Vibrio cholerae O1, the major causative agent of cholera, remains a significant public health threat. Although there are available vaccines for cholera, the protection provided by killed whole-cell cholera vaccines in young children is poor. An obstacle to the development of improved cholera vaccines is the need for a better understanding of the primary mechanisms of cholera immunity and identification of improved correlates of protection. Considerable progress has been made over the last decade in understanding the adaptive and innate immune responses to cholera disease as well as V. cholerae infection. This review will assess what is currently known about the systemic, mucosal, memory, and innate immune responses to clinical cholera, as well as recent advances in our understanding of the mechanisms and correlates of protection against V. cholerae O1 infection.
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POPOVIC, TANJA, ØRJAN OLSVIK, PAUL A. BLAKE, and KAYE WACHSMUTH. "Cholera in the Americas: Foodborne Aspects." Journal of Food Protection 56, no. 9 (September 1, 1993): 811–21. http://dx.doi.org/10.4315/0362-028x-56.9.811.
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Over 100 serotypes of Vibrio cholerae exist, but generally the toxigenic strains of the serogroup O1 cause cholera and possess documented epidemic potential. The main symptom of cholera is a profuse diarrhea resulting in dehydration, that if untreated, leads to death. Seven pandemics of this contagious disease have been recorded during the last 200 years. A sick person secrets in his stool billions of organisms daily, and water and food contaminated with such a stool are the primary sources of infection during the epidemics. With the increase of the international food trade, food is often shipped from countries with endemic or epidemic cholera. With one exception, no documented cases of cholera have been reported, as a result of the internationally regulated food trade. However, during the present Latin American epidemic, inadequately cooked seafood has been implicated as a source of cholera. As a result of the epidemic, over 100 cases of cholera have occurred in the United States related to seafood consumed during a visit to Latin America or after its noncommercial transport into the country. Furthermore, V. cholerae persists as a free-living organism in environmental reservoirs in Australia and the U.S. Gulf Coast; there have been 65 domestically acquired cases of cholera in the United States since 1973. Molecular typing methods have enabled us to identify and characterize endemic and epidemic strains, and to document transmission of cholera when food was implicated epidemiologically as a vehicle of transmission.
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Morita, Masatomo, Makoto Ohnishi, Eiji Arakawa, Shouji Yamamoto, G. Balakrish Nair, Shigeru Matsushita, Keiko Yokoyama, et al. "Emergence and genetic diversity of El Tor Vibrio cholerae O1 that possess classical biotype ctxB among travel-associated cases of cholera in Japan." Journal of Medical Microbiology 59, no. 6 (June 1, 2010): 708–12. http://dx.doi.org/10.1099/jmm.0.017624-0.
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Vibrio cholerae O1 are classified into two biotypes, classical and El Tor, each encoding a biotype-specific cholera toxin. However, El Tor strains have recently emerged with a classical cholera-toxin genotype (El Tor variant). We characterized El Tor strains of V. cholerae O1 from travel-associated cases of cholera in Japan isolated from 1991 to 2006 by cholera toxin B subunit gene (ctxB) typing and by molecular epidemiological methods. ctxB in the biotype El Tor shifted from the El Tor-specific type to the classical-specific type around 1993, and this type fully dominated the later half of the 1990s. Based on the results of PFGE and multilocus variable-number tandem repeat analysis, strains of the classical biotype remained diverse from those of El Tor biotype. The El Tor biotype strains formed multiple minor clusters and intermingled with each other irrespective of their origins and toxin types. El Tor variant strains are widespread in Asian countries and show significant genetic diversity, indicating that their spread is a result of multiclonal expansion rather than spread from a single clone.
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Alam, Munirul, Marzia Sultana, G. Balakrish Nair, R. Bradley Sack, David A. Sack, A. K. Siddique, Afsar Ali, Anwar Huq, and Rita R. Colwell. "Toxigenic Vibrio cholerae in the Aquatic Environment of Mathbaria, Bangladesh." Applied and Environmental Microbiology 72, no. 4 (April 2006): 2849–55. http://dx.doi.org/10.1128/aem.72.4.2849-2855.2006.
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ABSTRACT Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be a source of culturable V. cholerae, even in nonepidemic periods. Biweekly environmental surveillance for V. cholerae was carried out in Mathbaria, an area of cholera endemicity adjacent to the Bay of Bengal, with the focus on V. cholerae O1 and O139 Bengal. A total of 297 samples of water, phytoplankton, and zooplankton were collected between March and December 2004, yielding eight V. cholerae O1 and four O139 Bengal isolates. A combination of culture methods, multiplex-PCR, and direct fluorescent antibody (DFA) counting revealed the Mathbaria aquatic environment to be a reservoir for V. cholerae O1 and O139 Bengal. DFA results showed significant clumping of the bacteria during the interepidemic period for cholera, and the fluorescent micrographs revealed large numbers of V. cholerae O1 in thin films of exopolysaccharides (biofilm). A similar clumping of V. cholerae O1 was also observed in samples collected from Matlab, Bangladesh, where cholera also is endemic. Thus, the results of the study provided in situ evidence for V. cholerae O1 and O139 in the aquatic environment, predominantly as viable but nonculturable cells and culturable cells in biofilm consortia. The biofilm community is concluded to be an additional reservoir of cholera bacteria in the aquatic environment between seasonal epidemics of cholera in Bangladesh.
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Bartlett, D. H. "MICROBIOLOGY: Chitin, Cholera, and Competence." Science 310, no. 5755 (December 16, 2005): 1775–77. http://dx.doi.org/10.1126/science.1122396.
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Namdari, Hassan, Christine R. Klaips, and Joan L. Hughes. "A Cytotoxin-Producing Strain of Vibrio choleraeNon-O1, Non-O139 as a Cause of Cholera and Bacteremia after Consumption of Raw Clams." Journal of Clinical Microbiology 38, no. 9 (2000): 3518–19. http://dx.doi.org/10.1128/jcm.38.9.3518-3519.2000.
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We report a case of a cholera-like gastroenteritis subsequent with bacteremia in a healthy man following consumption of raw clams. Although we failed to recover the organism from the patient's stool culture, his blood culture was positive for a non-cholera toxin-producing yet cytotoxin-producing non-O1 and non-O139Vibrio cholerae.
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Chua, Ang Lim, Husni Tan Elina, Boon Huat Lim, Chan Yean Yean, Manickam Ravichandran, and Pattabhiraman Lalitha. "Development of a dry reagent-based triplex PCR for the detection of toxigenic and non-toxigenic Vibrio cholerae." Journal of Medical Microbiology 60, no. 4 (April 1, 2011): 481–85. http://dx.doi.org/10.1099/jmm.0.027433-0.
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Vibrio cholerae has caused severe outbreaks of cholera worldwide with thousands of recorded deaths annually. Molecular diagnosis for cholera has become increasingly important for rapid detection of cholera as the conventional methods are time-consuming and labour intensive. However, traditional PCR tests still require cold-chain transportation and storage as well as trained personnel to perform, which makes them user-unfriendly. The aim of this study was to develop a thermostabilized triplex PCR test for cholera which is in a ready-to-use form and requires no cold chain. The PCR test specifically detects both toxigenic and non-toxigenic strains of V. cholerae based on the cholera toxin A (ctxA) and outer-membrane lipoprotein (lolB) genes. The thermostabilized triplex PCR also incorporates an internal amplification control that helps to check for PCR inhibitors in samples. PCR reagents and the specific primers were lyophilized into a pellet form in the presence of trehalose, which acts as an enzyme stabilizer. The triplex PCR was validated with 174 bacteria-spiked stool specimens and was found to be 100 % sensitive and specific. The stability of the thermostabilized PCR was evaluated using the Q10 method and it was found to be stable for approximately 7 months at 24 °C. The limit of detection of the thermostabilized triplex PCR assay was 2×104 c.f.u. at the bacterial cell level and 100 pg DNA at the genomic DNA level, comparable to conventional PCR methods. In conclusion, a rapid thermostabilized triplex PCR assay was developed for detecting toxigenic and non-toxigenic V. cholerae which requires minimal pipetting steps and is cold chain-free.
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Harris, Aaron M., M. Saruar Bhuiyan, Fahima Chowdhury, Ashraful I. Khan, Azim Hossain, Emily A. Kendall, Atiqur Rahman, et al. "Antigen-Specific Memory B-Cell Responses to Vibrio cholerae O1 Infection in Bangladesh." Infection and Immunity 77, no. 9 (June 15, 2009): 3850–56. http://dx.doi.org/10.1128/iai.00369-09.
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ABSTRACT Cholera, caused by Vibrio cholerae, is a noninvasive dehydrating enteric disease with a high mortality rate if untreated. Infection with V. cholerae elicits long-term protection against subsequent disease in countries where the disease is endemic. Although the mechanism of this protective immunity is unknown, it has been hypothesized that a protective mucosal response to V. cholerae infection may be mediated by anamnestic responses of memory B cells in the gut-associated lymphoid tissue. To characterize memory B-cell responses to cholera, we enrolled a cohort of 39 hospitalized patients with culture-confirmed cholera and evaluated their immunologic responses at frequent intervals over the subsequent 1 year. Memory B cells to cholera antigens, including lipopolysaccharide (LPS), and the protein antigens cholera toxin B subunit (CTB) and toxin-coregulated pilus major subunit A (TcpA) were enumerated using a method of polyclonal stimulation of peripheral blood mononuclear cells followed by a standard enzyme-linked immunospot procedure. All patients demonstrated CTB, TcpA, and LPS-specific immunoglobulin G (IgG)and IgA memory responses by day 90. In addition, these memory B-cell responses persisted up to 1 year, substantially longer than other traditional immunologic markers of infection with V. cholerae. While the magnitude of the LPS-specific IgG memory B-cell response waned at 1 year, CTB- and TcpA-specific IgG memory B cells remained significantly elevated at 1 year after infection, suggesting that T-cell help may result in a more durable memory B-cell response to V. cholerae protein antigens. Such memory B cells could mediate anamnestic responses on reexposure to V. cholerae.
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Nasreen, Tania, Nora A. S. Hussain, Jia Yee Ho, Vanessa Zhi Jie Aw, Munirul Alam, Stephanie K. Yanow, and Yann F. Boucher. "Assay for Evaluating the Abundance of Vibrio cholerae and Its O1 Serogroup Subpopulation from Water without DNA Extraction." Pathogens 11, no. 3 (March 16, 2022): 363. http://dx.doi.org/10.3390/pathogens11030363.
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Cholera is a severe diarrheal disease caused by Vibrio cholerae, a natural inhabitant of brackish water. Effective control of cholera outbreaks depends on prompt detection of the pathogen from clinical specimens and tracking its source in the environment. Although the epidemiology of cholera is well studied, rapid detection of V. cholerae remains a challenge, and data on its abundance in environmental sources are limited. Here, we describe a sensitive molecular quantification assay by qPCR, which can be used on-site in low-resource settings on water without the need for DNA extraction. This newly optimized method exhibited 100% specificity for total V. cholerae as well as V. cholerae O1 and allowed detection of as few as three target CFU per reaction. The limit of detection is as low as 5 × 103 CFU/L of water after concentrating biomass from the sample. The ability to perform qPCR on water samples without DNA extraction, portable features of the equipment, stability of the reagents at 4 °C and user-friendly online software facilitate fast quantitative analysis of V. cholerae. These characteristics make this assay extremely useful for field research in resource-poor settings and could support continuous monitoring in cholera-endemic areas.
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de Magny, Guillaume Constantin, Pronob K. Mozumder, Christopher J. Grim, Nur A. Hasan, M. Niamul Naser, Munirul Alam, R. Bradley Sack, Anwar Huq, and Rita R. Colwell. "Role of Zooplankton Diversity in Vibrio cholerae Population Dynamics and in the Incidence of Cholera in the Bangladesh Sundarbans." Applied and Environmental Microbiology 77, no. 17 (July 15, 2011): 6125–32. http://dx.doi.org/10.1128/aem.01472-10.
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ABSTRACTVibrio cholerae, a bacterium autochthonous to the aquatic environment, is the causative agent of cholera, a severe watery, life-threatening diarrheal disease occurring predominantly in developing countries.V. cholerae, including both serogroups O1 and O139, is found in association with crustacean zooplankton, mainly copepods, and notably in ponds, rivers, and estuarine systems globally. The incidence of cholera and occurrence of pathogenicV. choleraestrains with zooplankton were studied in two areas of Bangladesh: Bakerganj and Mathbaria. Chitinous zooplankton communities of several bodies of water were analyzed in order to understand the interaction of the zooplankton population composition with the population dynamics of pathogenicV. choleraeand incidence of cholera. Two dominant zooplankton groups were found to be consistently associated with detection ofV. choleraeand/or occurrence of cholera cases, namely, rotifers and cladocerans, in addition to copepods. Local differences indicate there are subtle ecological factors that can influence interactions betweenV. cholerae, its plankton hosts, and the incidence of cholera.
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Dalsgaard, A., A. Forslund, N. V. Tam, D. X. Vinh, and P. D. Cam. "Cholera in Vietnam: Changes in Genotypes and Emergence of Class I Integrons Containing Aminoglycoside Resistance Gene Cassettes in Vibrio cholerae O1 Strains Isolated from 1979 to 1996." Journal of Clinical Microbiology 37, no. 3 (1999): 734–41. http://dx.doi.org/10.1128/jcm.37.3.734-741.1999.
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The number of cholera cases and the mortality rates reported from different regions of Vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. Annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. Major cholera outbreaks were reported from the High Plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water supplies. All cases were associated with Vibrio cholerae O1. Using ribotyping, cholera toxin (CT) genotyping, and characterization of antibiotic susceptibility patterns and antibiotic resistance genes by PCR, we show that strains isolated after 1990 were clearly different from strains isolated before 1991. In contrast to strains isolated before 1991, 94% of 104 strains isolated after 1990 showed an identical ribotype R1, were resistant to sulfamethoxazole and streptomycin, and showed a different CT genotype. Furthermore, PCR analysis revealed that sulfamethoxazole-resistant strains harbored class I integrons containing a gene cassette ant(3")-1aencoding resistance to streptomycin and spectinomycin. This is, to our knowledge, the first report of class I integrons in V. cholerae. The development of cholera and the changes in the phenotypic and genotypic properties of V. cholerae O1 shown in the present study highlight the importance of monitoring V. cholerae O1 in Vietnam as in other parts of the world. In particular, the emergence of the new ribotype R1 strain containing class I integrons should be further studied.
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Alam, Munirul, Nur A. Hasan, Abdus Sadique, N. A. Bhuiyan, Kabir U. Ahmed, Suraia Nusrin, G. Balakrish Nair, et al. "Seasonal Cholera Caused by Vibrio cholerae Serogroups O1 and O139 in the Coastal Aquatic Environment of Bangladesh." Applied and Environmental Microbiology 72, no. 6 (June 2006): 4096–104. http://dx.doi.org/10.1128/aem.00066-06.
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ABSTRACT Since Vibrio cholerae O139 first appeared in 1992, both O1 El Tor and O139 have been recognized as the epidemic serogroups, although their geographic distribution, endemicity, and reservoir are not fully understood. To address this lack of information, a study of the epidemiology and ecology of V. cholerae O1 and O139 was carried out in two coastal areas, Bakerganj and Mathbaria, Bangladesh, where cholera occurs seasonally. The results of a biweekly clinical study (January 2004 to May 2005), employing culture methods, and of an ecological study (monthly in Bakerganj and biweekly in Mathbaria from March 2004 to May 2005), employing direct and enrichment culture, colony blot hybridization, and direct fluorescent-antibody methods, showed that cholera is endemic in both Bakerganj and Mathbaria and that V. cholerae O1, O139, and non-O1/non-O139 are autochthonous to the aquatic environment. Although V. cholerae O1 and O139 were isolated from both areas, most noteworthy was the isolation of V. cholerae O139 in March, July, and September 2004 in Mathbaria, where seasonal cholera was clinically linked only to V. cholerae O1. In Mathbaria, V. cholerae O139 emerged as the sole cause of a significant outbreak of cholera in March 2005. V. cholerae O1 reemerged clinically in April 2005 and established dominance over V. cholerae O139, continuing to cause cholera in Mathbaria. In conclusion, the epidemic potential and coastal aquatic reservoir for V. cholerae O139 have been demonstrated. Based on the results of this study, the coastal ecosystem of the Bay of Bengal is concluded to be a significant reservoir for the epidemic serogroups of V. cholerae.
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Huq, Anwar, R. Bradley Sack, Azhar Nizam, Ira M. Longini, G. Balakrish Nair, Afsar Ali, J. Glenn Morris, et al. "Critical Factors Influencing the Occurrence of Vibrio cholerae in the Environment of Bangladesh." Applied and Environmental Microbiology 71, no. 8 (August 2005): 4645–54. http://dx.doi.org/10.1128/aem.71.8.4645-4654.2005.
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ABSTRACT The occurrence of outbreaks of cholera in Africa in 1970 and in Latin America in 1991, mainly in coastal communities, and the appearance of the new serotype Vibrio cholerae O139 in India and subsequently in Bangladesh have stimulated efforts to understand environmental factors influencing the growth and geographic distribution of epidemic Vibrio cholerae serotypes. Because of the severity of recent epidemics, cholera is now being considered by some infectious disease investigators as a “reemerging” disease, prompting new work on the ecology of vibrios. Epidemiological and ecological surveillance for cholera has been under way in four rural, geographically separated locations in Bangladesh for the past 4 years, during which both clinical and environmental samples were collected at biweekly intervals. The clinical epidemiology portion of the research has been published (Sack et al., J. Infect. Dis. 187:96-101, 2003). The results of environmental sampling and analysis of the environmental and clinical data have revealed significant correlations of water temperature, water depth, rainfall, conductivity, and copepod counts with the occurrence of cholera toxin-producing bacteria (presumably V. cholerae). The lag periods between increases or decreases in units of factors, such as temperature and salinity, and occurrence of cholera correlate with biological parameters, e.g., plankton population blooms. The new information on the ecology of V. cholerae is proving useful in developing environmental models for the prediction of cholera epidemics.
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Krebs, Shelly J., and Ronald K. Taylor. "Nutrient-dependent, rapid transition of Vibrio cholerae to coccoid morphology and expression of the toxin co-regulated pilus in this form." Microbiology 157, no. 10 (October 1, 2011): 2942–53. http://dx.doi.org/10.1099/mic.0.048561-0.
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The acute diarrhoeal disease cholera is caused by the aquatic pathogen Vibrio cholerae upon ingestion of contaminated food or water by the human host. The mechanisms by which V. cholerae is able to persist and survive in the host and aquatic environments have been studied for years; however, little is known about the factors involved in the adaptation or response of V. cholerae transitioning between these two environments. The transition from bacillary to coccoid morphology is thought to be one mechanism of survival that V. cholerae uses in response to environmental stress. Coccoid morphology has been observed for V. cholerae while in a viable but non-culturable (VBNC) state, during times of nutrient limitation, and in the water-diluted stool of cholera-infected patients. In this study we sought conditions to study the coccoid morphology of V. cholerae, and found that coccoid-shaped cells can express and produce the virulence factor toxin co-regulated pilus (TCP) and are able to colonize the infant mouse to the same extent as bacillus-shaped cells. This study suggests that TCP may be one factor that V. cholerae utilizes for adaptation and survival during the transition between the host and the aquatic environment.
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LaRocque, Regina C., Jason B. Harris, Michelle Dziejman, Xiaoman Li, Ashraful I. Khan, Abu S. G. Faruque, Shah M. Faruque, et al. "Transcriptional Profiling of Vibrio cholerae Recovered Directly from Patient Specimens during Early and Late Stages of Human Infection." Infection and Immunity 73, no. 8 (August 2005): 4488–93. http://dx.doi.org/10.1128/iai.73.8.4488-4493.2005.
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ABSTRACT Understanding gene expression by bacteria during the actual course of human infection may provide important insights into microbial pathogenesis. In this study, we evaluated the transcriptional profile of Vibrio cholerae, the causative agent of cholera, in clinical specimens from cholera patients. We collected samples of human stool and vomitus that were positive by dark-field microscopy for abundant vibrios and used a microarray to compare gene expression in organisms recovered directly from specimens collected during the early and late stages of human infection. Our results reveal that V. cholerae gene expression within the human host environment differs from patterns defined in in vitro models of pathogenesis. tcpA, the major subunit of the essential V. cholerae colonization factor, was significantly more highly expressed in early than in late stages of infection; however, the genes encoding cholera toxin were not highly expressed in either phase of human infection. Furthermore, expression of the virulence regulators toxRS and tcpPH was uncoupled. Interestingly, the pattern of gene expression indicates that the human upper intestine may be a uniquely suitable environment for the transfer of genetic elements that are important in the evolution of pathogenic strains of V. cholerae. These findings provide a more detailed assessment of the transcriptome of V. cholerae in the human host than previous studies of organisms in stool alone and have implications for cholera control and the design of improved vaccines.
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Qadri, Firdausi, Muhammad Asaduzzaman, Christine Wennerås, Golam Mohi, M. John Albert, Mohammad Abdus Salam, R. Bradley Sack, et al. "Enterotoxin-Specific Immunoglobulin E Responses in Humans after Infection or Vaccination with Diarrhea-Causing Enteropathogens." Infection and Immunity 68, no. 10 (October 1, 2000): 6077–81. http://dx.doi.org/10.1128/iai.68.10.6077-6081.2000.
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ABSTRACT Cholera toxin (CT)-specific antibody responses of the immunoglobulin E (IgE) isotype in the sera of adult patients suffering from infection with either Vibrio cholerae O1, V. cholerae O139, or enterotoxigenic Escherichia coli(ETEC) were analyzed and compared with those in the sera of volunteers immunized with a bivalent B subunit O1/O139 whole-cell cholera vaccine. A significant IgE response to CT was observed in 90% of the patients with V. cholerae O1 infection (18 of 20; P = <0.001) and 95% of the patients with V. cholerae O139 infection (19 of 20; P = <0.001). Similarly, the majority of the patients with ETEC diarrhea (83%; 13 of 15) showed a positive IgE response to CT. Eight of 10 North American volunteers (80%) orally challenged with V. cholerae O1 showed CT-specific IgE responses (P = 0.004). In contrast, Swedish volunteers immunized with the oral cholera vaccine showed no IgE responses to CT (P value not significant). During the study period, total IgE levels in the sera of the diarrheal patients, the North American volunteers, and the Swedish cholera vaccinees alike remained unchanged. However, the total IgE levels in the sera of patients and healthy Bangladeshi controls were on average 89-fold higher than those in the sera of the healthy Swedish volunteers and 34-fold higher than those in the sera of the North American volunteers.
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Faruque, Shah M., M. John Albert, and John J. Mekalanos. "Epidemiology, Genetics, and Ecology of ToxigenicVibrio cholerae." Microbiology and Molecular Biology Reviews 62, no. 4 (December 1, 1998): 1301–14. http://dx.doi.org/10.1128/mmbr.62.4.1301-1314.1998.
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SUMMARY Cholera caused by toxigenic Vibrio cholerae is a major public health problem confronting developing countries, where outbreaks occur in a regular seasonal pattern and are particularly associated with poverty and poor sanitation. The disease is characterized by a devastating watery diarrhea which leads to rapid dehydration, and death occurs in 50 to 70% of untreated patients. Cholera is a waterborne disease, and the importance of water ecology is suggested by the close association of V. cholerae with surface water and the population interacting with the water. Cholera toxin (CT), which is responsible for the profuse diarrhea, is encoded by a lysogenic bacteriophage designated CTXΦ. Although the mechanism by which CT causes diarrhea is known, it is not clear why V. cholerae should infect and elaborate the lethal toxin in the host. Molecular epidemiological surveillance has revealed clonal diversity among toxigenic V. cholerae strains and a continual emergence of new epidemic clones. In view of lysogenic conversion by CTXΦ as a possible mechanism of origination of new toxigenic clones of V. cholerae, it appears that the continual emergence of new toxigenic strains and their selective enrichment during cholera outbreaks constitute an essential component of the natural ecosystem for the evolution of epidemic V. cholerae strains and genetic elements that mediate the transfer of virulence genes. The ecosystem comprising V. cholerae, CTXΦ, the aquatic environment, and the mammalian host offers an understanding of the complex relationship between pathogenesis and the natural selection of a pathogen.
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Noskov, A. K., V. D. Kruglikov, E. A. Moskvitina, E. V. Monakhova, D. A. Levchenko, E. G. Yanovich, A. S. Vodop’yanov, et al. "Characteristics of the Epidemiological Situation on Cholera in the World and in the Russian Federation in 2020 and Forecast for 2021." Problems of Particularly Dangerous Infections, no. 1 (April 16, 2021): 43–51. http://dx.doi.org/10.21055/0370-1069-2021-1-43-51.
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Aim of the work – to assess the epidemiological situation on cholera in 2020 and to make a forecast for 2021 based on the monitoring data and analysis of morbidity around the world for the period of 2011–2020. During the period between 2011 and 2020, 4 413 988 cases of cholera were recorded in 97 countries of the world with a general trend towards a decrease in the incidence (coefficient of accuracy of approximation R2 – 0.5705). However, due to the continuing epidemic manifestations of cholera in the endemic countries of Asia, Africa and America, the epidemiological situation on cholera on these continents was characterized as unfavorable in 2020. The emergence of a new “post-Haitian” lineage was observed among epidemically hazardous strains of Vibrio cholerae O1. In 2020, no epidemically dangerous strains of V. cholerae O1, O139 were isolated from humans on the territory of the Russian Federation. 25 non-toxigenic V. cholerae O1 El Tor strains were isolated from environmental objects, eight out of which (ctxA-, tcpA+), according to PCR-INDEL typing and SNP analysis of sequences, belonged to the clonal complex. The results of the analysis of biological properties and phylogenetic relations between the isolated non-toxigenic strains provided the basis for considering the epidemiological situation on cholera in Russia in 2020 as a stable one and a similar forecast of its development in 2021. At the same time, the possibility of importation of this infection from endemic countries cannot be ruled out, as well as the need to carry out a complex of differentiated anti-epidemic (preventive) measures within the framework of the state sanitary-epidemiological surveillance in order to localize and eliminate the imported focus and avoid the spread of the infection.
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Valle, Edgar, Talena Ledón, Bárbara Cedré, Javier Campos, Tania Valmaseda, Boris Rodríguez, Luis García, et al. "Construction and Characterization of a Nonproliferative El Tor Cholera Vaccine Candidate Derived from Strain 638." Infection and Immunity 68, no. 11 (November 1, 2000): 6411–18. http://dx.doi.org/10.1128/iai.68.11.6411-6418.2000.
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ABSTRACT In recent clinical assays, our cholera vaccine candidate strain,Vibrio cholerae 638 El Tor Ogawa, was well tolerated and immunogenic in Cuban volunteers. In this work we describe the construction of 638T, a thymidine auxotrophic version of improved environmental biosafety. In so doing, the thyAgene from V. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. Except for its dependence on thymidine for growth in minimal medium, 638T is essentially indistinguishable from 638 in the rate of growth and morphology in complete medium. The two strains showed equivalent phenotypes with regard to motility, expression of the celAmarker, colonization capacity in the infant mouse cholera model, and immunogenicity in the adult rabbit cholera model. However, the ability of this new strain to survive environmental starvation was limited with respect to that of 638. Taken together, these results suggest that this live, attenuated, but nonproliferative strain is a new, promising cholera vaccine candidate.
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Goel, A. K., and S. C. Jiang. "Association of Heavy Rainfall on Genotypic Diversity inV. choleraeIsolates from an Outbreak in India." International Journal of Microbiology 2011 (2011): 1–5. http://dx.doi.org/10.1155/2011/230597.
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The outbreak of waterborne disease cholera has been associated with rainfall and flooding events by contamination of potable water with environmentalVibrio cholerae. The continuation of the epidemic in a region, however, is often due to secondary transmission of the initial outbreak strain through human waste. This paper reports, on the contrary, a rapid shift of genotype from oneV. choleraestrain to another one in an epidemic region.V. choleraeisolated from patients during 2005 cholera epidemic in Chennai, India were characterized using PCR identification of toxin genes, antibiogram, and genomic fingerprinting analysis. The results showed that in spite of the similarity of toxin genes and antibiogram, theVibrioisolates grouped into two different clusters based on the ERIC-PCR fingerprinting. Each cluster corresponded to a distinct peak of cholera outbreak, which occurred after separate heavy rainfall. The results suggest that the rainfall event can bring various genotypes ofV. choleraestrains causing multiple outbreaks.
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Colwell, R. R., A. Huq, M. A. R. Chowdhury, B. Xu, and P. R. Brayton. "Serogroup conversion of Vibrio cholerae." Canadian Journal of Microbiology 41, no. 10 (October 1, 1995): 946–50. http://dx.doi.org/10.1139/m95-131.
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Vibrio cholerae serogroup O1 can be detected in the environment in a viable but nonculturable form, whereas V. cholerae non-O1 cells can be readily cultured during interepidemic periods in geographical regions where cholera is endemic. In the present study, pure cultures of V. cholerae non-O1 cells contained 01 cells when examined by immune-fluorescence microscopy. Laboratory microcosms were used to examine the outgrowth of the O1 cells in cultures of non-O1 V. cholerae. One O1 cell per 106 non-O1 cells could be detected by direct fluorescent-monoclonal antibody staining but only after incubation of the non-O1 culture for 48 h. Individual O1 cells were not detected in cultures incubated less than 48 h. Hybridization study, using a polymerase chain reaction (PCR) amplified fragment of the O-antigen of V. cholerae O1 as a probe, revealed the existence of a homologous gene in a microcosm sample of V. cholerae non-O1 containing serogroup-converted cells. The mechanism by which O1 cells can occur in cultures of non-O1 V. cholerae most likely resulted from spontaneous mutation of gene(s) encoding the O-somatic properties and (or) chemical, physical, or biological changes in the environment inducing expression or repression of the controlling gene(s). These findings have important implications for the epidemiology of cholera and the environmental source(s) of toxin producing V. cholerae O1.Key words: serogroup conversion, Vibrio cholerae O1, Vibrio cholerae non-O1, cholera.
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Kritsky, A. A., N. I. Smirnova, T. B. Kalyaeva, N. F. Obrotkina, I. V. Gracheva, A. D. Katyshev, and V. V. Kutyrev. "Comparative Analysis of Molecular-Genetic Properties in Non-Toxigenic Vibrio cholerae O1 Strains Biovar El Tor, Isolated in Russia and on Cholera Endemic Territories." Problems of Particularly Dangerous Infections, no. 3 (October 23, 2021): 72–82. http://dx.doi.org/10.21055/0370-1069-2021-3-72-82.
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Objective of the study was to perform a comparative analysis of molecular-genetic properties in non-toxigenic Vibrio cholerae O1 strains biovar El Tor, isolated in the Republic of Kalmykia and on cholera endemic territories and to reveal their phylogenetic relations to toxigenic isolates.Materials and methods. We have carried out bio-information analysis of whole genome sequences of 60 cholera vibrio strains from endemic as regards cholera regions and from Kalmykia. The presence of pathogenicity and endemicity islands in their genomes has been determined. Specifed have been the sequence-types of the examined strains and whole genome SNP-analysis conducted.Results and discussion. Non-toxigenic El Tor vibrios circulating in Kalmykia are clustered into two major genotypes: ctxA–tcpA+VPI-2+VSP– and ctxA–tcpA–VPI-2Δ+VSP–, where VPI-2 Δ+ signifes the presence of deletions of varying length in the genome of this pathogenicity island. Only the latter one is found in regions endemic for cholera. In addition, ctxA– tcpA+VPI-2+VSP+ populations circulate in cholera endemic foci, not found in Kalmykia. 17 sequence-types were identifed among the studied strains (by seven housekeeping gene loci). Phylogenetic analysis performed using SNP-typing demonstrated the absence of close genetic relation between the ctxA–tcpA+VPI-2+VSP– vibrios from Kalmykia and both toxigenic and non-toxigenic vibrios with different composition of pathogenicity and pandemicity islands in the genome. At the same time, genetic proximity of ctxA–tcpA–VPI-2Δ+VSP– cholera vibrios from endemic cholera foci with those isolated in Kalmykia was detected, which may indicate the possibility of their recurrent importation into the territory of Russia. Non-toxigenic V. cholerae strains found in the territory of Kalmykia are characterized by a high genetic diversity. Circulation of the strains with unique sequence-types suggests their potential for long-term persistence on this territory. At the same time, phylogenetic closeness and identity of certain strains with strains from endemic territories can be an evidence of repeated importation.
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Zahid, M. Shamim Hasan, S. M. Nashir Udden, A. S. G. Faruque, Stephen B. Calderwood, John J. Mekalanos, and Shah M. Faruque. "Effect of Phage on the Infectivity of Vibrio cholerae and Emergence of Genetic Variants." Infection and Immunity 76, no. 11 (September 15, 2008): 5266–73. http://dx.doi.org/10.1128/iai.00578-08.
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ABSTRACT Seasonal epidemics of cholera in Bangladesh are self-limited in nature, presumably due to phage predation of the causative Vibrio cholerae during the late stage of an epidemic, when cholera patients excrete large quantities of phage in their stools. To further understand the mechanisms involved, we studied the effect of phage on the infectivity and survival of V. cholerae shed in stools. The 50% infectious dose of stool vibrios in infant mice was ∼10-fold higher when the stools contained a phage (1.8 × 103 to 5.7 × 106 PFU/ml) than when stools did not contain a detectable phage. In competition assays in mice using a reference strain and phage-negative cholera stools, the infectivity of biofilm-like clumped cells was 3.9- to 115.9-fold higher than that of the corresponding planktonic cells. However, the difference in infectivity of these two cell populations in phage-positive stools was significantly less than that in phage-negative stools (P = 0.0006). Coculture of a phage and V. cholerae or dilutions of phage-positive cholera stools in nutrient medium, but not in environmental water, caused rapid emergence of phage-resistant derivatives of the bacteria, and these derivatives lost their O1 antigen. In cholera stools and in intestinal contents of mice prechallenged with a mixture of V. cholerae and phage, the bacteria remained completely phage susceptible, suggesting that the intestinal environment did not favor the emergence of phage-resistant derivatives that lost the O1 antigen. Our results indicate that phages lead to the collapse of epidemics by modulating the required infectious dose of the bacteria. Furthermore, the dominance of phage-resistant variants due to the bactericidal selective mechanism occurs rarely in natural settings, and the emerging variants are thus unable to sustain the ongoing epidemic.
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Harris, Jason B., Ashraful I. Khan, Regina C. LaRocque, David J. Dorer, Fahima Chowdhury, Abu S. G. Faruque, David A. Sack, Edward T. Ryan, Firdausi Qadri, and Stephen B. Calderwood. "Blood Group, Immunity, and Risk of Infection with Vibrio cholerae in an Area of Endemicity." Infection and Immunity 73, no. 11 (November 2005): 7422–27. http://dx.doi.org/10.1128/iai.73.11.7422-7427.2005.
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ABSTRACT Individuals with blood group O are more susceptible than other individuals to severe cholera, although the mechanism underlying this association is unknown. To assess the respective roles of both intrinsic host factors and adaptive immune responses that might influence susceptibility to infection with Vibrio cholerae, we prospectively followed a cohort of household contacts of patients with cholera in Bangladesh. In this study, we made the novel observation that persons with blood group O were less likely than those with other blood groups to become infected with V. cholerae O1 (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.53 to 0.85; P = 0.008). Consistent with prior studies, however, household contacts with blood group O were more likely to develop severe illness if infected with V. cholerae O1 (OR, 2.3; 95% CI, 0.98 to 5.59; P = 0.05). While blood group O protected significantly against infection with V. cholerae O1, there was no evidence of protection against V. cholerae O139. A multivariate analysis demonstrated that the association between blood group O and protection from infection with V. cholerae O1 was independent of age, gender, and baseline anti-cholera toxin and vibriocidal antibody titers. Based on this epidemiologic evidence, we propose a hypothesis for understanding the association between blood group O and the risk of infection with V. cholerae O1 and O139 as well as the risk of developing severe symptoms once infected.
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Wu, Jia-Yan, William F. Wade, and Ronald K. Taylor. "Evaluation of Cholera Vaccines Formulated with Toxin-Coregulated Pilin Peptide Plus Polymer Adjuvant in Mice." Infection and Immunity 69, no. 12 (December 1, 2001): 7695–702. http://dx.doi.org/10.1128/iai.69.12.7695-7702.2001.
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ABSTRACT Cholera is an acute diarrheal disease that is caused by the gram-negative bacterium Vibrio cholerae. The low efficacy of currently available killed-whole-cell vaccines and the reactinogenicity coupled with potential reversion of live vaccines have thus far precluded widespread vaccination for the control of cholera. Recent studies on the molecular nature of the virulence components that contribute to V. cholerae pathogenesis have provided insights into possible approaches for the development of a defined subunit cholera vaccine. Genetic analysis has demonstrated that the toxin-coregulated pilus (TCP) is the major factor that contributes to colonization of the human intestine by V. cholerae. In addition, polyclonal and several monoclonal antibodies directed against TCP have been shown to provide passive immunity to disease in the infant mouse cholera model. In the present study, synthetic peptides corresponding to portions of the C-terminal disulfide region of TcpA pilin were formulated with polymer adjuvants currently in clinical trials and used to actively immunize adult female CD-1 mice. The experimental vaccine formulations elicited high levels of antigen-specific immunoglobulin G (IgG), including a broad spectrum of subclasses (IgG1, IgG2a, IgG2b, and IgG3), and lower levels of IgA. Infant mice born to the immunized mothers showed 100% protection against a 50% lethal dose (1 LD50) challenge and 50% protection against a 10-LD50 challenge with virulent strain O395. These results indicate that specific regions of TcpA, including those delineated by the peptides used in this study, have the potential to be incorporated into an effective defined subunit vaccine for cholera.
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Parveen, Salina, Samuel R. Farrah, Celia Gonzalez-Bonilla, Altagracia V. Zamudio, and Mark L. Tamplin. "Characterization of a clinicalVibrio choleraeO139 isolate from Mexico." Canadian Journal of Microbiology 49, no. 1 (January 1, 2003): 65–70. http://dx.doi.org/10.1139/w03-004.
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Pathogenic strains of Vibrio cholerae O139 possess the cholera toxin A subunit (ctxA) gene as well as the gene for toxin co-regulated pili (tcpA). We report the isolation of a ctxA-negative, tcpA-negative V. cholerae O139 strain (INDRE1) from a patient in Mexico diagnosed with gastrointestinal illness. Certain phenotypic characteristics of this strain were identical to those of V. cholerae O1 biotype El Tor. Unlike ctxA-positive V. cholerae O139 strains, this strain was sensitive to a wide panel of antibiotics, including ampicillin, chloramphenicol, ciprofloxacin, gentamicin, furazolidone, nalidixic acid, nitrofurantoin, tetracycline, trimethoprim-sulfamethoxazole, and streptomycin, but was resistant to polymyxin B. Ribotype and pulsed-field gel electrophoresis profiles of INDRE1 differed from those of ctxA-positive V. cholerae O139 and other V. cholerae strains. Phenotypic characteristics of the Mexico strain were similar to those reported for V. cholerae O139 isolates from Argentina and Sri Lanka.Key words: Vibrio cholerae O139, cholera toxin, ctxA, tcpA.
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Rybal’chenko, D. A., E. Yu Shchelkanova, Yu V. Lozovsky, A. V. Fedorov, and N. I. Smirnova. "Prevalence of Different Types of Integrative Conjugative Element SXT/R391 Encoding Multiple Antibiotic Resistance Among Clinical Strains of Cholera Agent." Problems of Particularly Dangerous Infections, no. 1 (April 20, 2022): 137–47. http://dx.doi.org/10.21055/0370-1069-2022-1-137-147.
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The aim of the work was to study the prevalence of different types of SXT element with different composition of antibiotic resistance genes among clinical strains of the El Tor cholera pathogen isolated in Russia, Ukraine and cholera-endemic countries in Asia and Africa.Materials and methods. The subject of the study was 27 strains and nucleotide sequences of 77 strains of Vibrio cholerae El Tor available from the NCBI GenBank. The structure of the SXT element and its type were determined using the Mauve and BLAST v.2.9.0 programs. Phylogenetic relations of strains with different types of SXT were identified using Snippy v.4.6.0 and MrBayes v.3.2.7 software. Assessment of strain sensitivity to antibiotics was carried out in accordance with Methodological Regulations 4.2.2495-09.Results and discussion. Two types of SXT element (ICEVchInd5 and ICEVchBan9) have been identified among the studied strains from Russia and Ukraine, which have different composition of antibiotic resistance genes: floR, strAB, sul2, dfrA1 and floR, tetAR, strAB, sul2, dfrA1, respectively. At the same time, the studied strains from Asia and Africa contain five types of SXT: ICEVchInd5, ICEVchBan9, ICEVchBan5, SXTTET, ICEVchInd5ΔVRIII, which differ in size and/or composition of resistance genes. Of these, the last three have not been found in Russia and Ukraine. Due to the high level of genomic diversity of SXT in the population of V. cholerae in endemic regions, there is a risk of importation of cholera pathogen strains with altered resistance to antibiotics into Russia. Phylogenetic relations of 76 strains with different SXT types and different alleles of the ctxB gene encoding the B subunit of cholera toxin have been assessed based on SNP analysis. A close phylogenetic relation between strains with the same type of SXT isolated in Russia and Asian countries has been demonstrated, which confirms the importation of the causative agent of cholera with multiple resistance to antibiotics from this region and the need for constant monitoring of the sensitivity of V. cholerae to antimicrobial drugs.
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Tamplin, Mark L., Reema Jalali, Mohammed K. Ahmed, and Rita R. Colwell. "Variation in epitopes of the B subunit of Vibrio cholerae non-O1 and Vibrio mimicus cholera toxins." Canadian Journal of Microbiology 36, no. 6 (June 1, 1990): 409–13. http://dx.doi.org/10.1139/m90-071.
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Monoclonal antibodies reacting with the B subunit of Vibrio cholerae O1 strain 569B cholera toxin (CT-B) were used to identify unique and common epitopes of V. cholerae non-O1 and Vibrio mimicus CT-B. Vibrio cholerae non-O1 strains produced CT-B showing three monoclonal antibody reaction patterns (epitypes), which corresponded with epitypes described previously for V. cholerae O1 classical biotype CT-B (CT1), El Tor biotype CT-B (CT2), and a unique V. cholerae non-O1 CT-B (CT3), which lacked an epitope located in or near the GM1 ganglioside binding site of 569B CT-B. Vibrio mimicus CT-B was immunologically indistinguishable from 569B CT-B. These and previous results define six epitopes on 569B CT-B, and a fourth epitope in or near the GM1 ganglioside binding site. Key words: cholera toxin, epitopes, monoclonal antibodies.
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Kirn, Thomas J., and Ronald K. Taylor. "TcpF Is a Soluble Colonization Factor and Protective Antigen Secreted by El Tor and Classical O1 and O139 Vibrio cholerae Serogroups." Infection and Immunity 73, no. 8 (August 2005): 4461–70. http://dx.doi.org/10.1128/iai.73.8.4461-4470.2005.
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ABSTRACT Vibrio cholerae causes diarrhea by colonizing the human small bowel and intoxicating epithelial cells. Colonization is a required step in pathogenesis, and strains defective for colonization are significantly attenuated. The best-characterized V. cholerae colonization factor is the toxin-coregulated pilus (TCP). It has been demonstrated that TCP is required for V. cholerae colonization in both humans and mice. TCP enhances bacterial interactions that allow microcolony formation and thereby promotes survival in the intestine. We have recently discovered that the TCP biogenesis apparatus also serves as a secretion system, mediating the terminal step in the extracellular secretion pathway of TcpF. TcpF was identified in classical isolates of V. cholerae O1 as a soluble factor essential for colonization in the infant mouse cholera model. In the present study, we expanded our analysis of TcpF to include the O1 El Tor and O139 serogroups and investigated how TCP and TcpF act together to mediate colonization. Additionally, we demonstrated that antibodies generated against TcpF are protective against experimental V. cholerae infection in the infant mouse cholera model. This observation, coupled with the fact that TcpF is a potent mediator of colonization, suggests that TcpF should be considered as a component of a polyvalent cholera vaccine formulation.
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Fidelma Boyd, E., and Matthew K. Waldor. "Alternative Mechanism of Cholera Toxin Acquisition byVibrio cholerae: Generalized Transduction of CTXΦ by Bacteriophage CP-T1." Infection and Immunity 67, no. 11 (November 1, 1999): 5898–905. http://dx.doi.org/10.1128/iai.67.11.5898-5905.1999.
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ABSTRACT Horizontal transfer of genes encoding virulence factors has played a central role in the evolution of many pathogenic bacteria. The unexpected discovery that the genes encoding cholera toxin (ctxAB), the main cause of the profuse secretory diarrhea characteristic of cholera, are encoded on a novel filamentous phage named CTXΦ, has resulted in a renewed interest in the potential mechanisms of transfer of virulence genes among Vibrio cholerae. We describe here an alternative mechanism of cholera toxin gene transfer into nontoxigenic V. choleraeisolates, including strains that lack both the CTXΦ receptor, the toxin coregulated pilus (TCP), and attRS, the chromosomal attachment site for CTXΦ integration. A temperature-sensitive mutant of the V. cholerae generalized transducing bacteriophage CP-T1 (CP-T1ts) was used to transfer a genetically marked derivative of the CTX prophage into four nontoxigenicV. cholerae strains, including two V. choleraevaccine strains. We demonstrate that CTXΦ transduced by CP-T1ts can replicate and integrate into these nontoxigenic V. choleraestrains with high efficiency. In fact, CP-T1ts transduces the CTX prophage preferentially when compared with other chromosomal markers. These results reveal a potential mechanism by which CTXΦ+ V. cholerae strains that lack the TCP receptor may have arisen. Finally, these findings indicate an additional pathway for reversion of live-attenuated V. cholerae vaccine strains.
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Dupke, Susann, Kehinde A. Akinsinde, Roland Grunow, Bamidele A. Iwalokun, Daniel K. Olukoya, Afolabi Oluwadun, Thirumalaisamy P. Velavan, and Daniela Jacob. "Characterization of Vibrio cholerae Strains Isolated from the Nigerian Cholera Outbreak in 2010." Journal of Clinical Microbiology 54, no. 10 (August 3, 2016): 2618–21. http://dx.doi.org/10.1128/jcm.01467-16.
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We examined clinical samples from Nigerian patients with acute watery diarrhea forVibrio choleraeduring the 2010 cholera outbreak. A total of 109 suspected isolates were characterized, but only 57V. choleraestrains could be confirmed using multiplex real-time PCR as well asrpoBsequencing and typed asV. choleraeO:1 Ogawa biotype El Tor. This finding highlighted the need for accurate diagnosis of cholera in epidemic countries to implement life-saving interventions.
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Usmani, Moiz, Kyle D. Brumfield, Yusuf Jamal, Anwar Huq, Rita R. Colwell, and Antarpreet Jutla. "A Review of the Environmental Trigger and Transmission Components for Prediction of Cholera." Tropical Medicine and Infectious Disease 6, no. 3 (August 5, 2021): 147. http://dx.doi.org/10.3390/tropicalmed6030147.
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Climate variables influence the occurrence, growth, and distribution of Vibrio cholerae in the aquatic environment. Together with socio-economic factors, these variables affect the incidence and intensity of cholera outbreaks. The current pandemic of cholera began in the 1960s, and millions of cholera cases are reported each year globally. Hence, cholera remains a significant health challenge, notably where human vulnerability intersects with changes in hydrological and environmental processes. Cholera outbreaks may be epidemic or endemic, the mode of which is governed by trigger and transmission components that control the outbreak and spread of the disease, respectively. Traditional cholera risk assessment models, namely compartmental susceptible-exposed-infected-recovered (SEIR) type models, have been used to determine the predictive spread of cholera through the fecal–oral route in human populations. However, these models often fail to capture modes of infection via indirect routes, such as pathogen movement in the environment and heterogeneities relevant to disease transmission. Conversely, other models that rely solely on variability of selected environmental factors (i.e., examine only triggers) have accomplished real-time outbreak prediction but fail to capture the transmission of cholera within impacted populations. Since the mode of cholera outbreaks can transition from epidemic to endemic, a comprehensive transmission model is needed to achieve timely and reliable prediction with respect to quantitative environmental risk. Here, we discuss progression of the trigger module associated with both epidemic and endemic cholera, in the context of the autochthonous aquatic nature of the causative agent of cholera, V. cholerae, as well as disease prediction.
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Rollenhagen, Julianne E., Anuj Kalsy, Francisca Cerda, Manohar John, Jason B. Harris, Regina C. LaRocque, Firdausi Qadri, Stephen B. Calderwood, Ronald K. Taylor, and Edward T. Ryan. "Transcutaneous Immunization with Toxin-Coregulated Pilin A Induces Protective Immunity against Vibrio cholerae O1 El Tor Challenge in Mice." Infection and Immunity 74, no. 10 (October 2006): 5834–39. http://dx.doi.org/10.1128/iai.00438-06.
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ABSTRACT Toxin-coregulated pilin A (TcpA) is the main structural subunit of a type IV bundle-forming pilus of Vibrio cholerae, the cause of cholera. Toxin-coregulated pilus is involved in formation of microcolonies of V. cholerae at the intestinal surface, and strains of V. cholerae deficient in TcpA are attenuated and unable to colonize intestinal surfaces. Anti-TcpA immunity is common in humans recovering from cholera in Bangladesh, and immunization against TcpA is protective in murine V. cholerae models. To evaluate whether transcutaneously applied TcpA is immunogenic, we transcutaneously immunized mice with 100 μg of TcpA or TcpA with an immunoadjuvant (cholera toxin [CT], 50 μg) on days 0, 19, and 40. Mice immunized with TcpA alone did not develop anti-TcpA responses. Mice that received transcutaneously applied TcpA and CT developed prominent anti-TcpA immunoglobulin G (IgG) serum responses but minimal anti-TcpA IgA. Transcutaneous immunization with CT induced prominent IgG and IgA anti-CT serum responses. In an infant mouse model, offspring born to dams transcutaneously immunized either with TcpA and CT or with CT alone were challenged with 106 CFU (one 50% lethal dose) wild-type V. cholerae O1 El Tor strain N16961. At 48 h, mice born to females transcutaneously immunized with CT alone had 36% ± 10% (mean ± standard error of the mean) survival, while mice born to females transcutaneously immunized with TcpA and CT had 69% ± 6% survival (P < 0.001). Our results suggest that transcutaneous immunization with TcpA and an immunoadjuvant induces protective anti-TcpA immune responses. Anti-TcpA responses may contribute to an optimal cholera vaccine.
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Chaicumpa, Wanpen, Potjanee Srimanote, Yuwaporn Sakolvaree, Thareerat Kalampaheti, Manas Chongsa-Nguan, Pramuan Tapchaisri, Boonchuay Eampokalap, Pikul Moolasart, G. Balakrish Nair, and Peter Echeverria. "Rapid Diagnosis of Cholera Caused by Vibrio cholerae O139." Journal of Clinical Microbiology 36, no. 12 (1998): 3595–600. http://dx.doi.org/10.1128/jcm.36.12.3595-3600.1998.
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Hybridomas secreting specific monoclonal antibodies (MAbs) toVibrio cholerae serogroup O139 were produced. Six monoclones (hybridomas) secreting MAbs specific only to lipopolysaccharide of V. cholerae O139 strains and which did not cross-react to 137 strains of other enteric microorganisms were obtained. These clones were designated 12F5-G11, 12F5-G2, 15F5-H5, 5B9-F8, 14C9-D2, and 6D2-D8. The immunoglobulin (Ig) heavy chain isotypes secreted by these clones were IgG2b, IgG2b, IgG2b, IgM, IgG2b, and IgG3, respectively. Clone 12F5-G11 was selected for mass production of MAb, which was used as a detection reagent in the antigen detection assay for diagnosis of cholera caused by V. cholerae O139, and this assay was compared to the conventional bacterial isolation method. Five batches of rectal swab cultures in alkaline-peptone water were collected from 6,497 patients with watery diarrhea. These were 6,310 patients admitted to Bamrasnaradura Infectious Diseases Hospital, 16 patients from Krung Thon Hospital, 78 patients from Bangkok Children’s Hospital, 19 patients from Karen refugee camps, and 74 Indian patients from the National Institute of Cholera and Enteric Diseases, Calcutta, India. The V. cholerae O139 isolations from the rectal swab cultures and the antigen detection assays (i.e., the MAb-based dot-blot ELISA) were performed by different persons of different laboratories, and the results were revealed after all specimens had been tested. Of the 6,497 samples tested, the dot-blot ELISA correctly identified 42 of 42 V. choleraeO139-positive samples and gave a result of positive for three samples which were culture negative for V. cholerae O139. The diagnostic sensitivity, specificity, and efficacy of the dot-blot ELISA were 100, 99.95, and 99.26%, respectively. The ELISA is easy to perform and relatively inexpensive. It can test multiple samples at a single time, does not require special equipment, and does not produce great quantities of contaminated waste. Most of all, it reduces the diagnostic time from at least 2 days for the bacterial isolation to less than 90 min. The assay is recommended as a rapid screening test of cholera cases caused by V. cholerae O139.
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Dalsgaard, Anders, Anita Forslund, Andreas Petersen, Derek J. Brown, Francisco Dias, Serifo Monteiro, Kåre Mølbak, Peter Aaby, Amabelia Rodrigues, and Anita Sandström. "Class 1 Integron-Borne, Multiple-Antibiotic Resistance Encoded by a 150-Kilobase Conjugative Plasmid in Epidemic Vibrio cholerae O1 Strains Isolated in Guinea-Bissau." Journal of Clinical Microbiology 38, no. 10 (2000): 3774–79. http://dx.doi.org/10.1128/jcm.38.10.3774-3779.2000.
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In the 1996–1997 cholera epidemic in Guinea-Bissau, surveillance for antimicrobial resistance showed the emergence of a multidrug-resistant strain of Vibrio cholerae O1 during the course of the epidemic. The strain was resistant to ampicillin, erythromycin, tetracycline, furazolidone, aminoglycosides, trimethoprim, and sulfamethoxazole. Concomitant with the emergence of this strain, we observed a resurgence in the number of registered cholera cases as well as an increase in the case fatality rate from 1.0% before the emergence of the multiple-drug-resistant strain to 5.3% after the emergence of the strain. Our study shows that the strain contained a 150-kb conjugative multiple-antibiotic resistance plasmid with class 1 integron-borne gene cassettes encoding resistance to trimethoprim (dhfrXII) and aminoglycosides [ant(3")-1a]). The finding of transferable resistance to almost all of the antibiotics commonly used to treat cholera is of great public health concern. Studies should be carried out to determine to what extent the strain or its resistance genes have been spread to other areas where cholera is endemic.
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SHEIKH, A., A. KHAN, T. MALIK, and S. P. FISHER-HOCH. "Cholera in a developing megacity; Karachi, Pakistan." Epidemiology and Infection 119, no. 3 (December 1997): 287–92. http://dx.doi.org/10.1017/s0950268897008212.
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Despite rapid urbanization and increasing affluence in Karachi, cases of cholera are frequent. We analysed computerized isolation data from the AKUH Clinical Microbiology Laboratory, Karachi, from 1990–6 to examine microbiological, temporal and demographic trends in Vibrio cholerae infections. During this period 888 strains of V. cholerae (566 V. cholerae serogroup O1, and 204 V. cholerae serogroup O139) were isolated from specimens from 886 patients; 214/464 were adult inpatients, and 250/464 paediatric inpatients, the remaining 422 outpatients. Isolations peaked between June and August. Overlapping epidemics occurred in 1993 and 1994 of serogroup O1 (May to August), and serogroup O139 (August to October). All ages and social and economic strata were affected. Forty-four percent of all isolates were from children under the age of 5 years. The mean age of all patients with serogroup O1 infections was 19·6 years (±0·9) compared with 36·7 (±1·7) for serogroup O139 infections (P<0·0001, t test). More than a quarter (27%) of all serogroup O1 isolates were from babies under 2 years of age. One patient had a serogroup O1 infection followed by a serogroup O139 infection 1 year later. Another patient was infected with serogroup O1 strains 5 years apart. Emergence of resistant strains was observed, but by 1996 serogroup O139 had disappeared. An aquatic organism, cholera nevertheless continues to take its toll in this city of 11 million situated in a desert.
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Ul’yanov, A. Yu, O. D. Klokova, O. V. Gromova, V. R. Vol’nikov, O. A. Volokh, and A. K. Nikiforov. "Ways to Reduce the Level of Contamination at the Stages of Tableted Chemical Cholera Vaccine Production." Problems of Particularly Dangerous Infections, no. 1 (April 16, 2021): 152–55. http://dx.doi.org/10.21055/0370-1069-2021-1-152-155.
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Objective of the study was an assessment of the degree of contamination of cholera chemical vaccine at the stages of preparation and determination of the ways to reduce it.Materials and methods. Liquid and lyophilized components of the cholera chemical vaccine used in the study: cholerogen-anatoxin and O-antigens of Vibrio cholerae 569B and V. cholerae M-41 strains, as well as auxiliary substances (sucrose, talc, calcium stearate, starch). Granulation was carried out in a device that works on a fluidized bed principle, GPCG 2 (GLATT, Germany). Subsequent tabletizing of the mixture was performed using MiniTabT compression machine (LUXNER, Germany). Studies were conducted on the evaluation of “microbiological purity” at the stages of manufacturing of the cholera chemical vaccine, tablets coated with an enteric coating. Positive or negative growth of microorganisms on Petri dishes with nutrient media was determined on visual inspection.Results and conclusions. The dynamics of changes in microbial contamination at certain technological stages of vaccine production has been revealed. It is shown that the solutions of antigens in the process of separation are subject to microbial contamination which is associated with the use of ammonium sulfate during precipitation and non-sterile water at the stage of dialysis. Sterility of semi-finished products has been achieved through twophase filtration of choleragen-anatoxin and sterilization of O-antigens of V. cholerae 569B and V. cholerae M-41 strains with flowing steam at (100±1) °C for 30 minutes. In order to decrease microbial contamination at the stage of granulation additional fine filters were installed in the air-supply system. Further on comparative assessment of microbial purity of vaccine batches obtained using both, direct compression and preliminary granulation, was carried out. It has been experimentally demonstrated that granulation of the components of a tablet mixture of cholera vaccine leads to a decrease in the level of bacterial contamination and improves the microbiological purity of the finished dosage form.
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Cohen, Mitchell B., Ralph A. Giannella, Judy Bean, David N. Taylor, Susan Parker, Amy Hoeper, Stephen Wowk, et al. "Randomized, Controlled Human Challenge Study of the Safety, Immunogenicity, and Protective Efficacy of a Single Dose of Peru-15, a Live Attenuated Oral Cholera Vaccine." Infection and Immunity 70, no. 4 (April 2002): 1965–70. http://dx.doi.org/10.1128/iai.70.4.1965-1970.2002.
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ABSTRACT Peru-15 is a live attenuated oral vaccine derived from a Vibrio cholerae O1 El Tor Inaba strain by a series of deletions and modifications, including deletion of the entire CT genetic element. Peru-15 is also a stable, motility-defective strain and is unable to recombine with homologous DNA. We wished to determine whether a single oral dose of Peru-15 was safe and immunogenic and whether it would provide significant protection against moderate and severe diarrhea in a randomized, double-blind, placebo-controlled human volunteer cholera challenge model. A total of 59 volunteers were randomly allocated to groups to receive either 2 × 108 CFU of reconstituted, lyophilized Peru-15 vaccine diluted in CeraVacx buffer or placebo (CeraVacx buffer alone). Approximately 3 months after vaccination, 36 of these volunteers were challenged with approximately 105 CFU of virulent V. cholerae O1 El Tor Inaba strain N16961, prepared from a standardized frozen inoculum. Among vaccinees, 98% showed at least a fourfold increase in vibriocidal antibody titers. After challenge, 5 (42%) of the 12 placebo recipients and none (0%) of the 24 vaccinees had moderate or severe diarrhea (≥3,000 g of diarrheal stool) (P = 0.002; protective efficacy, 100%; lower one-sided 95% confidence limit, 75%). A total of 7 (58%) of the 12 placebo recipients and 1 (4%) of the 24 vaccinees had any diarrhea (P < 0.001; protective efficacy, 93%; lower one-sided 95% confidence limit, 62%). The total number of diarrheal stools, weight of diarrheal stools, incidence of fever, and peak stool V. cholerae excretion among vaccinees were all significantly lower than in placebo recipients. Peru-15 is a well-tolerated and immunogenic oral cholera vaccine that affords protective efficacy against life-threatening cholera diarrhea in a human volunteer challenge model. This vaccine may therefore be a safe and effective tool to prevent cholera in travelers and is a strong candidate for further evaluation to prevent cholera in an area where cholera is endemic.
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Nesper, Jutta, Anita Kraiß, Stefan Schild, Julia Blaβ, Karl E. Klose, Jochen Bockemühl, and Joachim Reidl. "Comparative and Genetic Analyses of the Putative Vibrio cholerae Lipopolysaccharide Core Oligosaccharide Biosynthesis (wav) Gene Cluster." Infection and Immunity 70, no. 5 (May 2002): 2419–33. http://dx.doi.org/10.1128/iai.70.5.2419-2433.2002.
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ABSTRACT We identified five different putative wav gene cluster types, which are responsible for the synthesis of the core oligosaccharide (OS) region of Vibrio cholerae lipopolysaccharide. Preliminary evidence that the genes encoded by this cluster are involved in core OS biosynthesis came from analysis of the recently released O1 El Tor V. cholerae genome sequence and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of O1 El Tor mutant strains defective in three genes (waaF, waaL, and wavB). Investigations of 38 different V. cholerae strains by Southern blotting, PCR, and sequencing analyses showed that the O1 El Tor wav gene cluster type is prevalent among clinical isolates of different serogroups associated with cholera and environmental O1 strains. In contrast, we found differences in the wav gene contents of 19 unrelated non-O1, non-O139 environmental and human isolates not associated with cholera. These strains contained four new wav gene cluster types that differ from each other in distinct gene loci, providing evidence for horizontal transfer of wav genes and for limited structural diversity of the core OS among V. cholerae isolates. Our results show genetic diversity in the core OS biosynthesis gene cluster and predominance of the type 1 wav gene locus in strains associated with clinical cholera, suggesting that a specific core OS structure could contribute to V. cholerae virulence.
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Stokes, Neil R., Xin Zhou, Stephen J. Meltzer, and James B. Kaper. "Transcriptional Responses of Intestinal Epithelial Cells to Infection with Vibrio cholerae." Infection and Immunity 72, no. 7 (July 2004): 4240–48. http://dx.doi.org/10.1128/iai.72.7.4240-4248.2004.
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ABSTRACT Vibrio cholerae is a noninvasive enteric bacterium that causes the severe diarrheal disease cholera. Candidate cholera vaccines have been engineered by deleting genes encoding known virulence factors in V. cholerae; however, many of these attenuated strains were still reactogenic in human volunteers. In this study, DNA arrays were utilized to monitor the transcriptional responses of human intestinal epithelial cells (T84) to eight strains of V. cholerae, including attenuated, toxigenic, and environmental isolates. cDNA probes generated from host RNA samples were hybridized against low- and high-density gene arrays. V. cholerae induced the transcription of a variety of host genes and repressed the expression of a lower number of genes. Expression patterns were confirmed for certain genes by reverse transcriptase PCR and enzyme-linked immunosorbent assays. A core subset of genes was found to be differentially regulated in all experiments. These genes included genes involved in innate mucosal immunity, intracellular signaling, and cellular proliferation. Reactogenic vaccine strains induced greater expression of genes for certain proinflammatory cytokines than nonreactogenic strains. Wild-type and attenuated derivatives induced and repressed many genes in common, although there were differences in the transcription profiles. These results indicate that the types of host genes modulated by attenuated V. cholerae, and the extent of their induction, may mediate the symptoms seen with reactogenic cholera vaccine strains.