Frequency of AmpC Beta-Lactamase Genes in Escherichia Coli Genera of Urinary Tract Infection Isolated from Patients Admitted to Internal Wards of Yazd Hospitals, Iran

Nowadays, beta-lactams are the most common antimicrobial agents used for treatment of bacterial infections. On the other hand, the production of beta-lactamase enzymes including AmpC is one of the reasons for bacterial resistance to antibiotics. The aim of this study was to determine the frequency of AmpC-type beta-lactamase genes in Escherichia coli isolated from patients with urinary tract infections.
In this cross-sectional study, 75 isolates of Escherichia coli were collected from the urine specimen of patients with urinary tract infections admitted to internal wards of Yazd hospitals, Iran. After culturing of specimens and isolation, identification of isolates was performed using biochemical tests and polymerase chain reaction (PCR) method. Disk diffusion method according to protocols of Clinical and Laboratory Standards Institute (CLSI-2016) was used for the susceptibility testing of isolates. AmpC genes were detected using PCR method and specific primers. The data were analyzed via SPSS software.
Findings: The highest and the lowest antibiotic resistance were observed for amoxicillin and imipenem, respectively. Out of 75 isolates, 19 isolates (25.3%) produced AmpC genes. blaCITM and blaDHAM genes were present in 13 (17.4%) and 2 (7.2%) Escherichia coli isolates, respectively. The blaFOXM gene was not detected in any of the isolates.
Our results indicate that AmpC genes are present in beta-lactamase-producing specimens, which is a serious threat for prescribing third-generation cephalosporins. In order to prevent the spread of these resistance, molecular methods-based studies should be performed to identify routine beta-lactamases such as AmpC.