Molecular Evidence for the Presence of enteroaggregative Escherichia coli (EAEC) among E. coli Isolates from Human Urinary Tract Infections

Background and Objectives:In 1991,EAEC O78:H10 strain was discovered to be the cause of urinary tract infection for the first time in Denmark. Later on, some studies showed that specific UPEC strains may carry EAEC virulence attributes , in the other word, EAEC strains may carry virulence factors that cause UTI . Therefore, it is interesting that some pathogenic strains share their virulence properties and make hybrid pathotypes such as EAEC/UPEC. Materials and methods: In this study, we examined a total of 38 E. coli isolates that were previously collected from human urinary tract infection in Mashhad (1395 to 1396). After culture on MacConkey agar and biochemical confirmation, a duplex PCR assay was performed to detect the typical EAEC and non-typical virulence markers including aggR and CVD432. Presence of other virulence genes of EAEC (aafA and aap) was also tested on PCR-positive isolates. Results: EAEC markers (aggR and CVD432) were detected in 7.8% (n=3) of strains. The aap were detected in 100% (n=3) of strains but none harbored the aafA gene. Conclusion : In this study we found EAEC isolates among UPEC strains, and given such findings, EAEC strains hav some roles in urinary tract infections in humans. Because EAEC have potential toforms biofilms the treatment o UTI du to EAE could be particularly difficult and should be considered in future studies.