Evaluating of Serological and Molecular Methods in Detection of Entropathogenic Escherichia Coli Isolated from Children with Diarrhea

Entropathogenic Escherichia coli (EPEC) are one of the major factors in children infection and continues diarrhea in the world. EPEC is one of the E.coli pathotypes with specific serogroups which can cause diarrhea in the children. The eae gene can be used for the molecular detection of these bacteria. In Iran clinical laboratories still use serogrouping for detection of EPEC which is suggested to produce false positive results.The aim of this study was to compare serogrouping and molecular methods for detection of EPEC and calculate sensitivity and specificity of serogrouping assay. A total of 885 E.coli were examined in this study and for each E.coli isolate serogrouping and molecular detection of eae gene with specific primer sets was conducted.The O serotyping method was used to identify the isolates belonging to commercially defined O serogroups. Isolates which could agglutinate with one of the specific commercial pathogenic O antisera were considered as suspected EPEC and subjected to molecular detection with primers specific for eae gene. Thirty five E.coli isolates belonging to one of the O serogroups were identified and characterized as suspected EPEC. Of these just 10 isolates harbor eae gene while 68 isolate of all 885 E.coli isolates carried eae gene and identified as EPEC. The result of this study strongly confirm that serogrouping which is a usual method for detection of EPEC in clinical laboratory in Iran leads to false positive and negative results and should be replaced with more reliable molecular methods.