Purification and characterization of cytotoxin produced by a clinical isolate of Vibrio cholerae O54 TV113.

Vibrio cholerae O54 TV113 isolated from a diarrheal patient produces an extracellular cytotoxin that caused alteration in the morphology of Chinese hamster ovary cells manifested as cell shrinkage with intact cell boundaries and finally causing cell death. Syncase medium supplemented with lincomycin (50 μg/ml), pH 7.2, and 18 h incubation with shaking at 37 °C supported optimal cytotoxin production.

Molecular characterization of Vibrio cholerae O139 bengal isolated from water and the aquatic plant Eichhornia crassipes in the River Ganga, Varanasi, India.

A collection of ten strains of Vibrio cholerae O139, comprising six isolates from Eichhornia crassipes, two from water of the River Ganga, and one each from a well and a hand pump, were characterized. All the strains carried the CTX genetic element (ctxA, zot, and ace) except for the st gene and carried structural and regulatory genes for toxin-coregulated pilus (tcpA, tcpI, and toxR), adherence factor (ompU), and accessory colonization factor (acfB); all produced cholera toxin (CT). These strains were resistant to trimethoprim, sulfamethoxazole, streptomycin, and to the vibriostatic agent pteridine.

Characterization of a toxigenic Vibrio cholerae O139 strain belonging to a new ribotype and isolated from a diarrheal patient.

We characterized a Vibrio cholerae O139 strain isolated from a diarrheal patient admitted to Taluk Hospital, Cherthala, Alleppey, Kerala, India, on 9 June 2000. The V. cholerae O139 strain possesses the core of the CTX genetic element, colonization toxin-coregulated pilus, the adherence outer membrane protein, and the central regulatory protein encoded by toxR and produces cholera toxin (200 pg/ml).

Development of a hexaplex PCR assay for rapid detection of virulence and regulatory genes in Vibrio cholerae and Vibrio mimicus.

We have developed a hexaplex PCR assay for rapid detection of the virulence and regulatory genes for cholera toxin enzymatic subunit A (ctxA), zonula occludens toxin (zot), accessory cholera enterotoxin (ace), toxin-coregulated pilus (tcpA), outer membrane protein (ompU), and central regulatory protein ToxR (toxR) in Vibrio cholerae and Vibrio mimicus. This hexaplex PCR proved successful in screening pathogenic-toxigenic and nonpathogenic-nontoxigenic V. cholerae and V.