Serotyping, Antibiotic Susceptibility Pattern and Detection of hlyA Gene Among Cholera Patients in Iran

Cholera is a severe diarrheal illness caused by vibrio cholerae, which producesa virulence factor named el tor hemolysin encoded by the hlya gene.objectives: this study meant to analyze the phenotypic characteristics and presence ofhlya gene in v. cholerae isolated from patients in iran. the hlya gene which codes for hemolysin,plays an essential role in manifestation of cholera ,and could be used to diagnosepathogenic v. cholerae el tor o1 strains.patients and methods: one hundred stool samples from the patients with cholera during2002-2003 were collected from tehran, kashan, kermanshah and ahvaz cities, whichwere subject to diagnostic tests. serotyping, and antibiotic susceptibility tests were appliedand polymerase chain reaction (pcr) was also used to detect the hlya gene.results: the group specific antisera identified the isolates as ogawa, inaba, hikojimaand nag (non-agglutinable) in 74%, 3%, 0% and 23% of the isolates, respectively. antibioticsusceptibility test showed that all of the strains were sensitive to ciprofloxacin,gentamycin and doxycyclin but the isolates showed resistance to sulfamethoxazole/trimethoprim(74%), erythromycin (64%) and tetracycline (50%). v. cholerae el tor isolateswere 100% positive for hlya gene, but hemolysis phenotype characteristics were foundin 95% of the cases.conclusions:the results indicated that ogawa serotype was identified as the dominantserotype which revealed multiple antibiotic resistances to sulfamethoxazole/trimethoprim,oxytetracycline, erythromycin, tetracycline and chloramphenicol. the presenceof hlya gene in nonhemolytic strains of v. cholerae o1 biotype el tor indicated thatsome factors prevent expression of the hemolysin gene.