Bengal: el tor cholera vibrio in a new robe

Enterobacterial repetitive intergenic consensus sequences and the PCR to generate fingerprints of genomic DNAs from Vibrio cholerae O1, O139, and non-O1 strains

“…1). The relationship between toxigenic and nontoxigenic V. cholerae O1 isolates has been examined by MEE, and identical patterns were reported for 100% of the toxigenic strains and 30.4% of the nontoxigenic strains (42). By using ERIC-PCR, as described in this study, it is possible to differentiate toxigenic (FP1) from nontoxigenic (FP2) strains of V. cholerae O1.…”

“…Other methods were also used to distinguish different serovars and biotypes, such as RFLP- were also found to be low in sensitivity and did not allow distinction of strains within a species (2,42). In contrast, the approaches applied here and by Versalovic et al (42) are a simple and useful alternative to the other methods used to date, because ERIC primers are highly specific and the procedure rapidly distinguishes toxigenic strains from nontoxigenic strains of V. cholerae. Multiple colonies isolated from the same culture, as well as repeated isolation of the same strain over time, revealed a consistent pattern, demonstrating that the fingerprint is stable and specific to a given bacterial strain (28).…”

“…We also obtained the same fingerprint for epidemic V. cholerae O1 toxigenic strains from Brazil, Peru, and Mexico, as well as from V. cholerae O139 Bengal strains isolated in India. Similarity between strains of the epidemic serogroups O1 and O139 was also revealed by MEE, both O1 and O139 serogroups belonging to zymovar 14 (23,42), and by Southern blot and hybridization with a probe for the iron-regulated gene (2). ERIC-PCR is relatively easy and rapid to perform compared with restriction analysis, probing, or MEE.…”

“…It was established that there are at least four distinct toxigenic El Tor V. cholerae O1 clones: seventh pandemic (Eastern Hemisphere); U.S. Gulf Coast; Australia; and Latin America (48). Other methods were also used to distinguish different serovars and biotypes, such as RFLP- were also found to be low in sensitivity and did not allow distinction of strains within a species (2,42). In contrast, the approaches applied here and by Versalovic et al (42) are a simple and useful alternative to the other methods used to date, because ERIC primers are highly specific and the procedure rapidly distinguishes toxigenic strains from nontoxigenic strains of V. cholerae.…”

Toxin-co-regulated pilus cluster in non-O1, non-toxigenic Vibrio cholerae: evidence of a third allele of pilin gene

“…Classical and El Tor strains show important di¡erences in the tcpA gene which is only 77% homologous between these two biotypes, with most of the amino acid changes at the C terminus. The Bengal O139 isolate which, as several analyses suggest, originated from an El Tor strain [9,10], carries tcpA with a sequence identical to El Tor isolates [11]. The tcpA expression in classical and El Tor biotypes does not occur under the same experimental conditions [12], and is subject to complex regulatory mechanisms [13].…”