ompU genes in non-toxigenic Vibrio cholerae associated with aquaculture.
OBJECTIVE
The study was undertaken with the objective of understanding the virulence-associated genes of the CTX and TCP gene clusters in environmental isolates of Vibrio cholerae, an important human pathogen, isolated from the aquaculture environment. The involvement of the ompU gene in conferring bile resistance in these isolates was also evaluated.


RESULTS
The V. cholerae isolates were tested by PCR and fluorescent antibody test for O1 (Ogawa and Inaba) and O139 serotypes. All isolates were found to be non-toxigenic V. cholerae confirmed by their positive PCR reaction for toxR but negative for ctx, zot and tcp gene. The hlyA gene was detected in 85% of the strains and ompU in 77%. The results on the bactericidal effect of bile salts suggest that ompU may play a role in conferring bile resistance in non-O1/non-O139 strains.


CONCLUSIONS
The results of the study indicate that most environmental strains lacked the CTX and TCP gene clusters. However, most isolates had the hlyA gene indicating the potential of these environmental strains to cause mild gastroenteritis. It was also observed that strains lacking ompU showed less tolerance to bile salts.


CONCLUSIONS
Information on virulence factors of V. cholerae associated with aquaculture environment and products would be of value in risk assessment for human health.
Karunasagar
Indrani
I
Department of Fishery Microbiology, University of Agricultural Sciences, College of Fisheries, Mangalore, India.
Rivera
I
I
Joseph
B
B
Kennedy
B
B
Shetty
V R
VR
Huq
A
A
Karunasagar
Iddya
I
Colwell
R R
RR
D018829:Adhesins, Bacterial / Q000235:genetics*; D017756:Aquaculture; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001647:Bile Acids and Salts / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D014734:Vibrio cholerae / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics; D014871:Water Microbiology
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001647:Bile Acids and Salts; C096349:OmpU protein, Vibrio cholerae