Assessing clonal correlation of epidemic Vibrio cholerae isolates during 2011 in 16 provinces of Iran.

A total of 1,187 Vibrio cholerae isolates were received during 2011 cholera outbreaks from 16 provinces in different geographical location to Iranian reference Health laboratory. A random selection was performed, and 61 isolates were subjected to further investigations. Cholera cases were come up from May with nine cases and reached to its maximum rate at August (57 cases) and continued to October after which a fall occurred in September. All of the isolates were susceptible to three antimicrobial agents including ciprofloxacin, cefixime, and ampicillin. The highest rate of resistance was seen to nalidixic acid (96.7 %) and co-trimoxazole (91.8 %). Clonality of isolates was investigated through genotyping by PFGE method. A total of seven pulsotypes were obtained from 61 isolates under study. The pulsotypes were highly related with only 1-3 bands differences. Three pulsotypes (PT5, PT6, and PT7) constituted 93.4 % of total isolates. One environmentally isolated strain showed distinct pattern from clinical specimens. This strain although had no any evidence in identified cholera infections, highlighted selecting more environmental specimens in any future outbreaks as long as human samples. In conclusion, emergence and dominance of Ogawa serotypes after about 7 years in Iran are alarming due to fear of import of new V. cholerae clones from out of the country. Approximately, one third of patients in 2011 cholera outbreak in Iran were of Afghan or Pakistani nationality which makes the hypothesis of import of Ogawa serotype strains from neighboring countries more documented and signifies the need to monitor and protect the boundaries.

Phenotypic and genotypic characterization of Escherichia Coli O111 serotypes.

AIM: The purpose of this study was to characterize phenotypically and genotypically the serotypes of the E. coli O111 associated with diarrheal disease and assess the variation among serotypes in terms of specific virulence factors and HeLa cells adherence patterns. BACKGROUND: Escherichia coli O111 serogroups are prevalent in endemic or sporadic cases of diarrhea, especially in developing areas. PATIENTS AND METHODS: A total of 54 strains of E. coli O111 isolated from diarrheal and healthy cases were included in this study. Flagella antigens of motile and non-motile strains were identified by fliC-RFLP method (H types) and confirmed with agglutination test using H-specific antisera. All strains were tested for the presence of 5 different gene regions associated with virulence (eaeA, eaeB, bfpA, sxt and EAF plasmid) by PCR and the patterns of bacterial attachment to HeLa cells was assayed in cell culture. RESULTS: Of 54 E. coli O111 strains, 89% were typeable with standard H antisera and the remaining 11% of strains were non-motile (H -). Twenty-three different H type were distinguished among the O111 strains by PCR-RFLP. The most common serotypes included H21, H9, H2, H6 and H12 (48%). Serotypes O111:H9 were represented by strains with 2 patterns of virulence genes (eaeA (+) /bfpA (+) /EAE(+), and eaeA (+) /bfpA (-) /EAE(-) ) and serotype H14 was represented by strains with the single eaeA (+) /bfpA (+) /EAE(-) combination. Four distinct patterns of adherence were distinguished: LA, LLA, AA and DA. All of serotypes with the eaeA (+) /bfpA (+) /EAE(+), or eaeA(+)/bfpA(+)/EAE(-), combination isolated from children with diarrhea exhibited the LA pattern, and serotypes with eaeA(+)/bfpA(-)/EAF(-) showed the LLA, while the majority of the strains isolated from healthy cases exhibited the DA, AA and NA patterns. CONCLUSION: Strains of this O serogroup represented a diverse of serotypes with a variety of virulence factors and mechanisms of pathogenesis.