Frequency of Enteroaggregative Escherichia coli isolates among patients with diarrhea referred to Tehran hospitals

Enteroaggregative E. coli (EAEC), after enterotoxigenic E. coli (ETEC) is the leading cause of traveler's diarrhea in developing and developed countries. According to importance of chronic diarrhea, especially in children, and inappropriate traditional methods, and insufficient informations about ferequency of EAEC, molecular techniques can be very helpful. In the current study, EAEC ferequency were evaluated among E.coli isolates among patients with and without diarrhea which were referred to selected hospitals of Tehran using PCR.
In this case-contro study, 165 diarrheal and 165 non-diarrheal samples were tested for E.coli using culture methods. Then DNA of isolates were extracted by the boiling method. All E.coli isolates were investigated for the presence of uidA gene. EAEC pathotypes were identified by amplification of the aggR gene using PCR. The statistical analysis was performed by chi square and fisher tests.
By culture methods, among 165 diarrheal and 165 non-diarrheal samples, 154 and 146 E.coli isolates were detected, respectively. According to uidA gene PCR results, 140 of diarrheal and 136 of non-diarrheal E.coli isolates were confirmed and others were excluded. The aggR gene was detected in 6 (4.28%) E.coli isolates of diarrheal and not found in non-diarrheal isolates.
The results showed that EAEC pathotypes have remarkable role in diarrhea, which usually ignored due to weakness of culture methods. According to importance of diarrhea, especially in infants and immune compromised patients, applying of molecular methods such as PCR can be helpful for diagnosis and treatment of acute and life-threatening cases.