Molecular identification of some virulence related genes for E. coli O157:H7 isolated from bloody diarrhea and UTI in Baghdad city.


This study was carried out for detection of some virulence factors for E coli O157:H7 isolated from patients with bloody hemorrhagic diarrhea or urinary tract infection (UTI). A total of 200 bloody diarrhea and 150 urine samples were collected from children of both sexes between the age of 3 and 10 years, who were suffering from bloody diarrhea and urinary tract infection (UTI) in the period from September to December 2016 in, Central Children Hospital and Children Safe Hospital in Baghdad/Iraq. All samples were screened to detect the presence of non-sorbitol fermenting colonies on sorbitol MacConkey agar supplemented with Cefixime -Tellurite (CT-SMAC) also cultured on other enrichment and selective media(Hicrome and Eosin methylen blue) at 37°C for 24hrs. The isolates were identified by Vitek 2 system and they were confirmed by latex agglutination test. A total of 11 isolate, 8 (4%) from bloody diarrhea and 3 (2%) isolates from urine samples were diagnosed as E. coli O157:H7 that appeared on CT-SMAC as small, circular and colorless colonies with smoky center whereas on Hicrome media as dark purple to magenta colored moiety colonies, positive for Vitek2 and latex agglutination. Polymerase chain reaction (PCR) was employed to detect some virulence genes of isolates ,as hlyA (responsible for hemolysine) flicH7 (encoding fimbria) and rfbO157 (encoding- lipopolysaccharide) using specific primers of 534, 625 and 259 bp for previous genes respectively . The result of PCR amplification revealed presence of hly A , flic H7 and rfb O157 genes in all isolate.