Phenotypic and Genotypic Characterization of ESBL- and Carbapenemase-producing Escherichia coli Isolates in Irritable Bowel Syndrome (IBS) Patients

INTRODUCTION: The prevalence of irritable bowel syndrome (IBS) is estimated to range from 10% to 20%. The symptoms of IBS have been associated with an increased presence of Escherichia coli bacteria in the bowel. Treatment is often complicated by the growing prevalence of antibioticresistant strains, particularly those producing extended-spectrum β-lactamases (ESBLs) and carbapenemases. Given the clinical significance of antibiotic resistance in E. coli among IBS patients, this study aimed to investigate the phenotypic and genotypic characteristics of ESBL- and carbapenemase-producing E. coli isolates. METHODS: The isolates were obtained from stool samples of IBS patients and identified using conventional biochemical methods. Phenotypic tests were conducted to detect ESBL- and carbapenemaseproducing strains. Polymerase chain reaction (PCR) was employed to identify genes associated with ESBL and carbapenemase production. Additionally, biofilm formation was assessed using a microtiter plate assay. RESULTS: A total of 67 E. coli isolates were recovered from patients. Of these, 37 (55.2%) were phenotypically positive for ESBL or carbapenemase production. PCR analysis revealed that 18 isolates (26.9%) harbored at least one ESBL gene, while 16 (23.9%) carried at least one carbapenemaserelated gene. The most prevalent ESBL gene was blaTEM (23.9%), while blaOXA-23 and blaKPC were the most common carbapenemase genes (each found in 10.4% of isolates). Notably, all isolates exhibited biofilm-forming ability, with nearly half (49.25%) forming strong biofilms. CONCLUSION: The notable prevalence of ESBL- and carbapenemase-producing E. coli among IBS patients may significantly affect patient outcomes, underscoring the need for targeted antibiotic stewardship and monitoring of biofilm-forming, drug-resistant strains.