Osong Public Health Res Perspect.  2021 Dec;12(6):390-395. 10.24171/j.phrp.2021.0272.

Prevalence of plasmid-mediated AmpC β-lactamases among uropathogenic Escherichia coli isolates in southwestern Iran

• Jomehzadeh N
• Ahmadi K
• Rahmani Z

• KMID: 2524376
• DOI: http://doi.org/10.24171/j.phrp.2021.0272

Abstract

Objectives
This study was undertaken to evaluate AmpC β-lactamase-producing Escherichia coli urine isolates and to characterize the frequency of plasmid-mediated AmpC (pAmpC)-encoding genes.
Methods
Antimicrobial susceptibility tests were performed using the disk diffusion technique. AmpC β-lactamase production was assessed with a phenotypic inhibitor-based method. The presence of 6 pAmpC-encoding cluster genes was detected by multiplex polymerase chain reaction (PCR).
Results
The proportion of antibiotic resistance of E. coli isolates ranged from 7.4% to 90.5%, and more than half (51.6%) of the total isolates were multidrug-resistant (MDR). Among the 95 E. coli isolates, 60 (63.2%) were found to be cefoxitin-resistant, but only 14 (14.7%) isolates were confirmed as AmpC β-lactamase-producers. In the PCR assay, pAmpC-encoding genes were found in 15 (15.8%) isolates, and blaDHA was the most prevalent type. However, blaFOX, blaMOX, and blaACC genes were not detected in the isolates.
Conclusion
Our findings contributed valuable information concerning antibiotic resistance, confirmatory phenotypic testing for AmpC production, and pAmpC β-lactamase gene content in E. coli isolates in southwestern Iran. The level of MDR recorded in AmpC-producing strains of this study was worrying; therefore, implementing strong infection control approaches to reduce the MDR burden is recommended.

Keyword

AmpC; Multidrug resistance; Urinary tract infections