Fluoroquinolone-resistant Vibrio cholerae isolated during a cholera outbreak in India

During the cholera epidemic of 2002 in and around Hubli, south India, Vibrio cholerae strains resistant to fluoroquinolones were isolated. Among the isolates of V. cholerae non-O1, non-O139 serogroups, 55.9% and 47.1% were resistant to norfloxacin and ciprofloxacin, respectively. However, only 12.5% of the O1 serogroup strains were resistant to both norfloxacin and ciprofloxacin. Though the O139 serogroup strains were susceptible to these antibiotics, they exhibited multidrug resistance. Emergence of fluoroquinolone-resistant V. cholerae that also exhibited multidrug resistance is of great significance in the epidemiology and control of cholera.     

Diversity of Vibrio cholerae strains isolated in Delhi, India, during 1992-2000

The National Institute of Communicable Diseases (NICD), Delhi, India, conducts a laboratory-based surveillance of cholera cases referred from the Infectious Disease Hospital, Delhi. The prevalence and antimicrobial susceptibilities of Vibrio cholerae O1, O139, and others, isolated from cholera patients for nine years, were analyzed to determine the changing trends in their isolation and drug-resistance patterns. In total, 29,196 stool samples or rectal swabs, collected during April 1992-December 2000, were included in this study. Of these, 13,730 (47%) were positive for V. cholerae: 11,091 for V. cholerae O1 (80.7%) and 1,943 (14%) for V. cholerae O139, and 696 (5%) were non-O1 and non-O139. V. cholerae O1 was the dominant serotype during 1992-1993, when V. cholerae O139 emerged as a new serotype but, thereafter, remained low from 1994 to 1999. Phenotypically, re-emerged V. cholerae O139 in 2000 displayed a difference compared to those that appeared in 1992-1993, in that the current O139 strains were sensitive to co-trimoxazole. Resistance to nalidixic acid and furazolidone was constantly high (100%) among strains of V. cholerae O1 and O139. All strains of V. cholerae were uniformly susceptible to chloramphenicol, tetracycline, amikacin, and norfloxacin. Molecular studies revealed different clones of V. cholerae O1 and O139 prevailing in the country with the re-emergence of V. cholerae O139 of a different clonality in Delhi in 2000, which is likely to play a critical role in temporal antigenic variation among the serogroups of V. cholerae.     

A high proportion of Vibrio cholerae strains isolated from children with diarrhoea in Bangkok, Thailand are multiple antibiotic resistant and belong to heterogenous non-O1, non-O139 O-serotypes.

Results of a surveillance on cholera conducted with patients seen at the Children Hospital in Bangkok, Thailand from August 1993 to July 1995 are presented. Annually, isolation rates for Vibrio cholerae varied between 1.7 and 4.4% of patients with diarrhoea. V. cholerae O1 serotype Ogawa accounted for between 31 and 47% of patients cultured positive for V. cholerae, whereas the O139 serotype dominated in early 1994 after which it disappeared. Non-O1, non-0139 strains were isolated at similar rates as serotype O1 in 1993 and 1994, but accounted for 69% of V. cholerae culture positive specimens in 1995. However, the annual proportion of the isolation of non-O1, non-O139 strains showed little variation and remained low between 1.0 and 1.3%. Serotyping of 69 epidemiological unrelated non-O1, non-O139 strains produced 37 different O-serotypes. BglI ribotyping of serotypes containing more than two strains demonstrated a high degree of heterogeneity within and between serotypes, except seven serotype O37 strains which showed an identical ribotype suggesting clonality. None of the 69 strains hybridized with a cholera toxin probe and only two strains hybridized with a heat-stable enterotoxin probe. Susceptibility testing to 12 antibiotics showed that 40 of 69 (58%) non-O1, non-O139 strains were resistant to colistin, streptomycin and sulphisoxazole and 28 of 69 (41%) were multiple antibiotic resistant (MAR; > or = 4 antibiotics). Although 26 of 69 (38%) strains contained one or more plasmids, the plasmids were of low molecular weights and did not seem to encode antibiotic resistance. The results of the present study showed that a high proportion of heterogenous MAR V. cholerae non-O1, non-O139 strains were isolated from children at the hospital. With reference to the emergence of V. cholerae O139 in 1992, we suggest that non-O1, non-O139 strains should be monitored carefully to detect new serotypes with a possible epidemic potential, but also to determine the development and mechanism of antibiotic resistance.     

Distribution and virulence of Vibrio cholerae belonging to serogroups other than O1 and O139: a nationwide survey.

The distribution and virulence of Vibrio cholerae serogroups other than O1 and O139 in India before, during and after the advent of O139 serogroup was investigated. A total of 68 strains belonging to 31 different ''O'' serogroups were identified during the study period. With the exception of O53, there was no spatial or temporal clustering of any particular non-O1 non-O139 serogroup at any given place. Two of the 68 strains examined produced cholera toxin (CT) which could only be partially absorbed with anti-CT immunoglobulin G. Tissue culture assay revealed that some of the non-O1 non-O139 strains produced factors which evoked either a cell rounding or cell elongation response depending upon the medium used. This study indicates that serogroups other than O1 and O139 should also be continuously monitored.     

Biotype traits and antibiotic susceptibility of Vibrio cholerae serogroup O1 before, during and after the emergence of the O139 serogroup.

Sixty-nine strains of Vibrio cholerae O1 isolated at different times were analysed to investigate if there were any differences among the O1 strains isolated before, during and after the advent of the O139 serogroup. Of the 69 O1 strains examined, 68 belonged to the Ogawa serotype while one belonged to the Inaba serotype. With the exception of one strain all other strains of V. cholerae O1 belonged to the eltor biotype. A single O1 strain isolated before the emergence of the O139 serogroup could not be classified as either eltor or classical biotype because it was resistant to both classical and eltor specific bacteriophages. Marked variations in the susceptibility to antibiotics of V. cholerae O1 isolated during the different periods were observed. In addition, strains of V. cholerae isolated after the epidemic of serogroup O139 in Calcutta showed an expanding R-type with resistance to a variety of drugs as compared to the O1 strains isolated before the advent of the O139 serogroup. From this study, it is clear that there is a substantial mobility in genetic elements of V. cholerae O1 which necessitates a continuous monitoring to keep abreast of the changing traits of the etiologic agent of cholera.     

Phenotypic and genetic analyses of 111 clinical and environmental O1, O139, and non-O1/O139 Vibrio cholerae strains from different geographical areas

A total of 111 clinical and environmental O1, O139 and non-O1/O139 Vibrio cholerae strains isolated between 1978 and 2008 from different geographical areas were typed using a combination of methods: antibiotic susceptibility, biochemical test, serogroup, serotype, biotype, sequences containing variable numbers of tandem repeats (VNTRs) and virulence genes ctxA and tcpA amplification. As a result of the performed typing work, the strains were organized into four clusters: cluster A1 included clinical O1 Ogawa and O139 serogroup strains (ctxA(+) and tcpA(+)); cluster A2 included clinical non-O1/O139 strains (ctxA(-) and tcpA(-)), as well as environmental O1 Inaba and non-O1/O139 strains (ctxA(-) and tcpA(-)/tcpA(+)); cluster B1 contained two clinical O1 strains and environmental non-O1/O139 strains (ctxA(-) and tcpA(+)/tcpA(-)); cluster B2 contained clinical O1 Inaba and Ogawa strains (ctxA(+) and tcpA(+)). The results of this work illustrate the advantage of combining several typing methods to discriminate between clinical and environmental V. cholerae strains.     

Genetic diversity and antibiotic resistance of clinical and environmental Vibrio Cholerae suggests that many serogroups are reservoirs of resistance

Vibrio cholerae is an important human pathogen and the cause of cholera. Since genetic variation and antibiotic resistance of strains have implications for effective treatment of the disease, we examined the genetic diversity and antibiotic resistance profile in 92 clinical strains (serogroup O1) and 56 environmental strains (O1 antigen, 42 strains; non-O1 antigen, 14 strains) isolated in Brazil between 1991 and 1999. Clinical and environmental O1 strains showed greater drug resistance compared to environmental non-O1 strains. Nearly all clinical O1 strains were resistant to one or more antibiotics while half of the environmental O1 and non-O1 strains were resistant to one or more antibiotics. No plasmids or class 1 integrons were detected in the strains by PCR analysis. Multilocus enzyme electrophoresis analysis (MLEE) suggests most of the O1 strains belong to a single (South American) clone that is related but different to seventh-pandemic strains isolated from other parts of the world. Our results show that there is a close genetic relationship between clinical and environmental O1 strains and that many serogroups and the environment can be a reservoir for antibiotic resistance.     

Incidence and molecular analysis of Vibrio cholerae associated with cholera outbreak subsequent to the super cyclone in Orissa,India

An epidemiological study was carried out to find out the aetiological agent for diarrhoeal disorders in the cyclone and flood affected areas of Orissa, India. Rectal swabs collected from 107 hospitalized diarrhoea patients were bacteriologically analysed to isolate and identify the various enteropathogens. Detection of toxic genes among E. coli and V. cholerae was carried out by polymerase chain reaction (PCR) assay. Of the 107 rectal swabs analysed, 72.3% were positive for V. cholerae O1 Ogawa, 7.2% for V. cholerae O139, 1.2% for E. coli (EAggEC) and 1.2% for Shigella flexneri type 6. Using multiplex PCR assay it was found that all V. cholerae isolates were ctxA positive and El Tor biotype. Strains of V. cholerae O1 were observed to be resistant to nalidixic acid, furazolidone, streptomycin, co-trimoxazole and ampicillin. Except for nalidixic acid, the resistance pattern for O139 was identical to that of O1 strains. Representative strains of V. cholerae were further characterized by randomly amplified polymorphic DNA (RAPD) analysis and ribotyping. Both O1 and O139 V. cholerae strains exhibited the R3 pattern of ribotype and belonged to a similar pattern of RAPD compared with that of Calcutta strains. Early bacteriological and epidemiological investigations have revealed the dominance of V. cholerae O1 among the hospitalized patients in cyclone affected areas of Orissa. Drinking water scarcity and poor sanitation were thought to be responsible for these diarrhoeal outbreaks. Timely reporting and implementation of appropriate control measures could contain a vital epidemic in this area.     

Association of a disease approximating cholera caused by Vibrio cholerae of serogroups other than O1 and O139.

One hundred and six patients suffering from severe dehydrating diarrhoea were studied of whom 36 patients were positive for Vibrio cholerae. Out of 36, 15 were positive for V. cholerae O1, 10 for V. cholerae O139 and 11 for V. cholerae non-O1 non-O139. O1 and O139 were positive for the 301-bp ctxA amplicon and 471-bp tcpA amplicon indicating that the strains possessed toxigenic capability whereas no non-O1 non-O139 strain possessed ctxA or tcpA genes. Post-admission severity of purging and amount of ORS required were less in the V. cholerae non-O1 non-O139 group (P < 0.05) compared to the V. cholerae O1 and O139 groups. It appears from this study that a cholera-like clinical condition can be caused in the absence of CT as exemplified by strains of non-O1 non-O139.     

2005年上海市霍乱弧菌菌株表型及ctxA毒力基因分析

目的：分析本市2005年不同来源01群和0139群霍乱弧菌菌株表型和ctxA毒力基因特征。方法：以PCR方法，对所有菌株进行ctxA毒力基因检测。采用WHO推荐的改良K—B纸片法，对所有菌株均进行了12种抗菌药物的药敏试验。结果：从病人和外环境中分离出的0139群霍乱弧菌均为产毒株；从病人中分离出的01群霍乱弧菌流行株均产毒，外环境中分离出的非流行株少数也产毒。0139群霍乱弧菌菌株耐药谱较01群霍乱弧菌菌株广；两者对氨苄青霉素、强力霉素、庆大霉素、复方新诺明、利福平耐药率有显著差异。结论：本市2005年霍乱的流行株都是产毒株，但产毒株不一定是流行株。药敏结果显示，对01群和0139群霍乱弧菌应采取不同抗菌治疗，0139群霍乱弧菌多重耐药应引起重视。     

Minimum inhibitory concentration (MIC) of some antibiotics against Vibrio cholerae O139 isolates from Pondicherry.

The antibiotic susceptibility pattern of Vibrio cholerae O139, Bengal, an emerging intestinal pathogen has been determined by the Kirby Bauer technique and the MIC values of some antibiotics against these strains by agar dilution technique. All the strains were susceptible to tetracycline, norfloxacin, ciprofloxacin and a majority was susceptible to gentamicin (95.7%) and nalidixic acid (82.9%). Only 51% were susceptible to cefotaxime and most strains were resistant to furazolidone (95.7%), ampicillin (87.3%) and co-trimoxazole (91.5%). The study shows the importance of judicious use of antibiotics in cholera cases and the need for monitoring the susceptibility status of these strains particularly because of their ability to cause extra-intestinal infections like septicaemia.     

Preferential association of the heat-stable enterotoxin gene (stn) with environmental strains of Vibrio cholerae belonging to the O14 serogroup

Toxigenic Vibrio cholerae O1 and O139 serogroups have the capacity of causing epidemic and pandemic cholera but are infrequently found in the environment. The other serogroups are abundant in aquatic environments but do not possess the virulence genes necessary for causing the disease. Of the 559 environmental strains of V. cholerae, collected during different periods from environmental samples in Calcutta, 9 (1.6%) harboured the heat-stable enterotoxin gene (stn). Six of the 9 strains belonged to the O14 serogroup. Thus, V. cholerae strains carrying the stn gene revealed preferential association with the O14 serogroup. Three of the six strains harboured the tcpA gene of the E1 Tor type, which is an unusual feature among environmental V. cholerae strains. A strain that possessed the E1 Tor type tcpA also had the CTX prophage. Pulsed field gel electrophoresis (PFGE) revealed that the stn gene positive O14 strains of V. cholerae were not clonal.     

Molecular analysis of vibrio cholerae strains isolated in Malaysia: public health implications

The genetic diversity or clonality among Vibrio cholerae O1, O139 and non-O1/ non-O139 of clinical and environmental origin using ribotyping and PFGE was performed in order to ascertain the public health implications of the different genotypes circulating within the Malaysian environment. Using an in-house typing scheme, of the 214 strains included, 202 strains were isolated locally between 1992 and 1998, seven were obtained from Bangladesh and five were reference strains. Amongst the 176 El Tor O1 strains, 152 clinical strains demonstrated five ribotypes--E1a, E1b, E2a, E3 and E1c. E1b was the most predominant ribotype demonstrated by 84% of the El Tor O1 strains and was present in all years demonstrating that this strain was intrinsic to Malaysia. PFGE analysis of these strains demonstrated minimal variation amongst the 15 PFGE profiles obtained. Ribotpye E2a amongst five clinical and two environmental O1 strains, were from one location and had previously been reported in Indonesia and the Philippines, thus demonstrating strong evidence that these strains may have been imported into Malaysia. Among Vibrio cholerae O139 strains, 91.7% were of ribotype A1a similar to the original O139, while two others were of ribotype A1b and one of A1e, corresponding to ribotypes 1, 2 and 3 of Dalsgaard and colleagues' scheme for O139 strains. PFGE analysis demonstrated that 89% of ribotype A1a could be differentiated into three PFGE genotypes which were very closely related. The eight non-O1/non-O139 serogroup strains were heterogeneous in both ribotype and PFGE patterns.     

Ribotypes of clinical Vibrio cholerae non-O1 non-O139 strains in relation to O-serotypes

The emergence of Vibrio cholerae O139 in 1992 and reports of an increasing number of other non-O1 serogroups being associated with diarrhoea, stimulated us to characterize V. cholerae non-O1 non-O139 strains received at the National Institute of Infectious Diseases, Japan for serotyping. Ribotyping with the restriction enzyme BglI of 103 epidemiological unrelated mainly clinical strains representing 10 O-serotypes yielded 67 different typing patterns. Ribotype similarity within each serotype was compared by using the Dice coefficient (Sd) and different levels of homogeneity were observed (serotypes O5, O41 and O17, Sd between 82 and 90%: serotypes O13 and O141 Sd of 72; and O2, O6, O7, O11, O24 Sd of 62-66%). By cluster analysis, the strains were divided into several clusters of low similarity suggesting a high level of genetic diversity. A low degree of similarity between serotypes and ribotypes was found as strains within a specific serotypes often did not cluster but clustered with strains from other serotypes. However, epidemiological unrelated O5 strains showed identical or closely related ribotypes suggesting that these strains have undergone few genetic changes and may correspond to a clonal line. Surprisingly, 10 of 16 O141 strains studied contained a cholera toxin (CT) gene, including 7 strains recovered from stool and water samples in the United States. This is to our knowledge the first report of CT-positive clinical O141 strains. The closely related ribotypes shown by eight CT-positive strains is disturbing and suggest that these strains may be of a clonal origin and have the potential to cause cholera-like disease. Despite the low degree of correlation found between ribotypes and serotypes, both methods appears to be valuable techniques in studying the epidemiology of emerging serotypes of V. cholerae.     

An epidemic of cholera due to Vibrio cholerae O139 in Dhaka, Bangladesh: clinical and epidemiological features.

We describe the disease spectrum and socio-demographic and epidemiological features of an epidemic of cholera due to a new pathogen, Vibrio cholerae O139, in patients attending a very large hospital in the metropolitan city of Dhaka, Bangladesh. This hospital treats 70,000-90,000 patients a year with diarrhoeal diseases. A 4% systematic sample of 1854 patients attending from January to April 1993 were studied. Five hundred and two (27%) of the 1854 patients were culture positive for V. cholerae O139 and 63 (3%) were culture positive for V. cholerae O1 biotype El Tor. Patients with V. cholerae O139 were mainly adults with a short history of watery diarrhoea. Eight-three percent of patients had moderate to severe dehydration. All recovered except one 80-year-old man with compromised renal function who died. Seventy-eight percent of patients required initial intravenous rehydration followed by oral rehydration therapy with rice ORS; they also received tetracycline to reduce diarrhoea severity. Most patients were from urban slums with inadequate sanitation facilities and hygiene practices. The newly recognized V. cholerae O139 infection produced an epidemic of severe dehydrating diarrhoea indistinguishable from clinical cholera in a population which experiences two epidemic peaks of cholera in a year due to V. cholerae O1. Infection with the latter does not appear to confer any cross-protection from V. cholerae O139. The new pathogen suppressed, albeit temporarily, V. cholerae O1. Unlike other non-O1 serogroups of V. cholerae this new serogroup appears to have epidemic potential.     

Comparison of amplified fragment length polymorphism and pulsed-field gel electrophoresis for subtyping of Vibrio cholerae serogroups O1 and O139

Molecular typing of Vibrio cholerae strains is a powerful tool for the surveillance of cholera. Amplified fragment length polymorphism (AFLP) is considered to be a powerful subtyping technique to distinguish bacterial strains at the genetic level. Optimization and standardization of AFLP protocol is required to allow data comparisons across different laboratories in a surveillance network. Here, we performed AFLP using different restriction enzymes and primer pairs for subtyping of V. cholerae serogroups O1 and O139 and compared the optimized AFLP protocol with pulsed-field gel electrophoresis (PFGE) to evaluate the applicability of AFLP for conducting epidemiological surveillance of cholera. The discriminatory index (D-value) of PFGE for serogroup O1 strains was similar when digested with NotI and SfiI, whereas that for O139 strains was higher for NotI digestion than for SfiI. EcoRI-G/MseI-T was the restriction enzyme and primer combination with highest discriminatory index used in the AFLP analysis. Capillary electrophoresis-based AFLP showed higher discriminatory power than that of polyacrylamide gel electrophoresis-based AFLP. When the two methods were compared using 72 epidemiologically unrelated serogroup O1 El Tor isolates, AFLP had a lower D-value than PFGE with NotI and SfiI digestions, respectively. For 54 epidemiologically unrelated serogroup O139 isolates, NotI PFGE had the highest discriminatory power, and SfiI PFGE and AFLP yielded almost the same but lower discriminatory power. We conclude that NotI and SfiI are both suitable for the PFGE of V. cholerae serogroup O1, whereas NotI should be defined as the primary enzyme for serogroup O139. The applicability of AFLP in V. cholerae subtyping and outbreak investigations is limited.     

The prevalence of Vibrio spp. in drinking water and environmental samples in Vellore South India.

The prevalence of Vibrio cholerae in drinking water, lakes and sewage outfalls during July and August 1996 in Vellore, India was determined. Drinking water samples were collected on single occasions from 12 sites in different geographic areas of the town where cholera had been reported. Samples of water, plankton and sediment were collected from fixed sites at three lakes on three occasions separated by at least 3 days during the course of the study. Samples from open sewers were taken from two representative sites in four areas of the town. Bacteria isolated from samples were identified by standard biochemical tests and isolated strains of V. cholerae tested for their ability to agglutinate O1 and O139 antisera. Water samples from lakes were also tested for the presence of V. cholerae O1 and O139 by fluorescent antibody staining. Non-O1, non-O139 strains of V. cholerae were detected in 41% of drinking water samples and 100% of water, sediment and plankton samples from the test lakes. Eighty-seven per cent of open sewers sampled contained viable non-O1, non-O139 V. cholerae. Fluorescent antibody staining gave positive results for V. cholerae O1 and O139 for all water samples from the three lake sites. Strains of Aeromonas spp. were isolated from 58% of drinking water samples and from 66% of sediment, 77% of plankton and 55% of water samples from lakes. All open sewers sampled contained Aeromonas spp. PCR amplification employing specific primers demonstrated that none of the non-agglutinating V. cholerae isolates contained the ctx operon. The non-O1, non-O139 V. cholerae isolates showed different patterns of antibiotic resistance to ampicillin, ciprofloxacin, chloramphenicol, tetracycline and trimethoprim.     

可疑霍乱弧菌的实验鉴定

目的:对4株可疑霍乱弧菌进行种属鉴定。方法:对可疑菌落在传统血清学和系统生化鉴定的基础上进行细菌的分子鉴定:应用16S rDNA的序列分析进行细菌种属鉴定和实时荧光PCR检测O1、O139群霍乱弧菌。结果:16 s rDNA基因序列分析显示041和067为麦氏弧菌,059和074为霍乱弧菌;荧光定量PCR检测结果说明4株菌都不是O1和O139霍乱弧菌。结论:结合血清凝集和系统生化实验,可以确定041和067为麦氏弧菌,059和074为非O1/非O139霍乱弧菌。对于可疑和难鉴别的霍乱弧菌,不能单纯依靠血清学和表型鉴定方法,需要分子诊断方法,尤其是16SrDNA的序列分析,可以从分子水平为弧菌科细菌的种属鉴定提供更为直接的证据。     

Characterization of Vibrio cholerae isolated from the aquatic basins of the State of Pernambuco, Brazil

Through a continuous bacteriological monitoring programme carried out by the Health Secretariat of the State of Pernambuco, Brazil, two isolates of Vibrio cholerae O1 El Tor Ogawa were discovered in an endemic area in 2001, during a cholera inactive period, along with six V. cholerae non-O1/non-O139 strains and two Aeromonas veronii biovar sobria strains showing an unusual characteristic of agglutination with O1 antiserum. Between that time and 2005, eight other O1 isolates were found. The virulence genes present in the V. cholerae differed among strains, with only three O1 strains harboring the ctxA gene. The O1 and some non-O1/non-O139 strains displayed identical patterns of amplification of the 16S-23S intergenic spacer region. RAPD of the 10 V. cholerae O1 strains, with the two primers used, revealed heterogeneity. The presence of V. cholerae carrying virulence genes in the aquatic basins examined confirms that they constitute a vibrio reservoir during a cholera inactive period, thus strengthening the argument for a continuous monitoring programme and preventative measures for cholera, mainly in the areas where the supply of drinking water is deficient.     

Molecular characterization of Vibrio cholerae O1 and non-O1 from human and environmental sources in Malaysia

A total of 31 strains of Vibrio cholerae O1 (10 from outbreak cases and 7 from surface water) and non-O1 (4 from clinical and 10 from surface water sources) isolated between 1993 and 1997 were examined with respect to presence of cholera enterotoxin (CT) gene by PCR-based assays, resistance to antibiotics, plasmid profiles and random amplified polymorphic DNA (RAPD) analysis. All were resistant to 9 or more of the 17 antibiotics tested. Identical antibiotic resistance patterns of the isolates may indicate that they share a common mode of developing antibiotic resistance. Furthermore, the multiple antibiotic resistance indexing showed that all strains tested originated from high risk contamination. Plasmid profile analysis by agarose gel electrophoresis showed the presence of small plasmids in 12 (7 non-O1 and 5 O1 serotypes) with sizes ranging 1.3-4.6 MDa. The CT gene was detected in all clinical isolates but was present in only 14 (6 O1 serotype and 8 non-O1 serotype) isolates from environmental waters. The genetic relatedness of the clinical and environmental Vibrio cholerae O1 and non-O1 strains was investigated by RAPD fingerprinting with four primers. The four primers generated polymorphisms in all 31 strains of Vibrio cholerae tested, producing bands ranging from < 250 to 4500 bp. The RAPD profiles revealed a wide variability and no correlation with the source of isolation. This study provides evidence that Vibrio cholerae O1 and non-O1 have significant public health implications.