Phylogenetic grouping and pathotypic comparison of urine and fecal Escherichia coli isolates from children with urinary tract infection

The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin..A) and trial (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and inal genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, 131, 132 and D) and that uropath.ogenic E. coli (UPEC) isolates mainly belong to groups 132 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal.E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p <0,05). mill gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed Ivgarding their phylogenetic groups, presence of class 1 integron and NO gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coll. isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC,