Epidemiologic evaluation of virulence genes, pap، sfa، cnf-1، hly in E. coli strains isolated from children with urinary tract infection

Urinary tract infection (UTI) caused by E coli is one of the most common diseases in children. Presence of four virulence genes of pap, sfa, hly and cnf have important role in organism pathogenicity and adhesion to epithelial cell. The present study was aimed to evaluate the prevalence of these four important virulence genes in E. coli strains isolated from urine samples of children with UTI and theircorrelation with clinical data. E. coli strains were isolated from urine samples of children with UTI who presented during 2005-2006 in Motahary hospital, Jahrom, Iran. The isolates were then studied for presence of genes hly,cnf-1, pap and sfa by PCR terchnique. Totally 96 E. coli strains were isolated from urine samples of children with UTI aged from 1 month to 14 years (mean 21.8± 26.9 months). Cystitis was diagnosed in 49.2% and pyelonephritis in 50.8% of these patients. Prevalence of genes pap, sfa, hly and cnf-1 among the strains was 27.1%, 14.6%, 13.5% and 22.9 %,respectively. Overall 32 samples (33.3%) were positive for at least one of the genes and 6 samples (6.3%) were positive for all four genes. pap and sfa were more common in ages over 36 months but hly was more detected in age under 48 months (P<0.05). cnf-1 gene was significantly more common in samples of the patients with abnormal kidney sonography (P=0.049). This study showed that the prevalence of virulence genes hly, cnf-1, pap and sfa in E. coli isolates was similar to the results of other studies. Because of higher prevalence of pyelonephritis in presence of these genes, rapid detection of the genes in urine samples may help in more suspicious and rapid management of pyelonephritis.