Molecular Identification of Escherichia coli Pathotypes and their Antimicrobial Resistance Profiles in Stool Samples Isolated from Patients in the West of Iran

Background: Gastroenteritis refers to an infection in the stomach and small intestine that may be caused by bacteria, viruses, and other pathogenic agents. Most strains of Escherichia coli (E. coli) in the gastrointestinal system have shared a symbiotic relationship with humans, but some serotypes are pathogenic. This study aimed to identify E. coli pathotypes isolated from stool samples and determine the antibiotic resistance profiles of these pathotypes in the west of Iran. Methods: The study was conducted on 106 samples of diarrheal feces which were sent to Imam Reza laboratory. First E. coli was detected and then the DNA was extracted. Next, the antibiotic sensitivity test was performed by the disk diffusion method. The E. coli pathotypes were qualitatively detected using the Amplisense EscherichiosesFRT PCR kit after DNA extraction from E. coli isolated in the stool sample. Results: In this study, out of 106 E. coli-positive samples, pathogenic E. coli were detected in 62 samples including 5 samples (8.1%) which only contained the EPEC pathotype, 10 samples (16.1%) contained only the EAEC pathotype, and 12 samples (19.4%) had only the EHEC pathotype. ETEC and EIEC were not isolated from any of the samples. The sensitivity to Meropenem (97%) and Gentamicin (96.2%) showed the highest frequency among the samples. The highest level of resistance was related to Amoxicillin (93.4%) and Ampicillin (78%). Conclusions: The epidemiological results show that the predominant pathotype among all isolates is EHEC and most antibiotic resistances were related to Amoxicillin and Ampicillin. Finally, a comprehensive molecular diagnosis of E. coli pathotypes, investigation of their incidence, and antibiogram profiles will help to determine better diagnostic and therapeutic measures for managing diarrheal diseases.