The prevalence of ESBL and AmpC β-lactamases in uropathogenic isolates of Escherichia coli in a tertiary care hospital in Southwest Iran

Abstract The aim of this study is to determine the molecular detection of AmpC β-lactamases (AmpC) and ESBLs, among clinical E. coli isolated from Namazi hospital in Shiraz, Iran. A total of 177 isolates from inpatients with UTI from different wards were identified as UPEC using the conventional microbiological tests. Phenotypic detection of ESBLs and Amp-C-β lactamase (Amp-C) production was done by various combinations of disc diffusion methods, followed by polymerase-chain-reaction for the detection of Amp-C and β-lactamase-encoding genes. The analysis showed that 46.3% of the isolates were ESBLs positive and that fifteen strains revealed the AmpC cluster genes. Among all ESBL-positive E. coli isolates, the CTX-M was the most prevalent ESBL type (68.2%), and in AmpC-positive isolates, fifteen isolates (88.2%) were positive for CITM cluster gene and two (11.7%) were positive for DHAM cluster gene. ACCM, FOXM, EBCM and MOXM cluster genes were not found in this study. Our findings revealed that the prevalence of AmpC β-lactamases is rising in Iran, leading to failure in treatment. Therefore, the current study recommended that accurate and precise methods and guidelines should be designed for detection of antibiotic-resistant mechanisms because it is very important for the treatment and prevention of such isolates.