RESUMO
An ecological and molecular-epidemiological study of Vibrio cholerae in some aquatic environments of Okayama was carried out. The strains of non-O1/non-O139 were isolated frequently, and unconventional O1 strains were rarely observed. These non-O1/non-O139 strains did not have ctxA, the gene of choleratoxin, the major pathogenic factor of epidemic cholera, but possessed hlyA, a gene encoding hemolysin thought to be a pathogenic factor for sporadic diarrhea or food poisoning. Furthermore these strains also had toxR, a gene controlling the pathogenic island of the V. cholerae genome, suggesting the potentia of these strains for accepting the horizontal transfer of virulence factor genes. Thus, continuous survey of the vibrio is to ensure the food safety of fishery products.
Assuntos
Ecologia , Vibrio cholerae/isolamento & purificação , Microbiologia da Água , Vibrio cholerae/genética , Vibrio cholerae/patogenicidadeRESUMO
An ecological study of pathogenic vibrios in aquatic environments of Okayama was carried out. The number of Vibrio parahaemolyticus detected in the sea area was comparatively smaler than that found in the survey of about two decades ago. Various reasons for the decrease in the case of food poisoning by V. parahaemolyticus have been suggested but the lower number of the vibrio in aquatic environments may be one explanation. Although the number of V. vulnificus was also not as large, most of the isolates possessed the pathogenic genes, vvp and vvh, suggesting the potential for fatal pathogenicity to patients having underlying diseases. As for V. cholerae, some non-O1/non-O139 serovar isolates were detected in a fresh water area, and many of them had hlyA, the gene for hemolysin which acts as a pathogenic factor in sporadic cases of diarrhea. Thus, the total number of pathogenic vibrios detected was not of concern. However, the marine products of these areas are shipped in wide area and are for general consumption. Therefore, it is necessary to continue to survey pathogenic vibrios in aquatic environments in order to ensure food hygiene.