AmpC β lactamases in Urinary Klebsiella pneumoniae Isolates: First Report of ACC Type AmpC β-lactamase Resistance in Iran

Background & Objective: The production of plasmid-mediated AmpC beta-lactamases (PMABLs) among urinary Klebsiella pneumoniae isolates causes a severe problem to the successful treatment of urinary tract infections (UTIs). This study was designed to evaluate antimicrobial resistance, the presence of AmpC beta-lactamase genes, and the genetic relatedness among K. pneumoniae strains separated from patients with UTI. Materials & Methods: In this cross-sectional descriptive study, a total of ۱۰۰ K. pneumoniae isolates were collected from UTI cases in Milad Hospital, Tehran, Iran. The sensitivity of the isolates to ۱۲ antibiotics was tested using the Kirby-Bauer disk diffusion method. AmpC production was determined using a boronic acid combined-disk test. Polymerase chain reaction (PCR) was carried out to screen all isolates with family-specific PMABL genes. The genetic relatedness of AmpC-producing isolates was determined by an enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Results: Over a period of ۱۱ months, PMABLs were detected in ۴۹ isolates (۴۹%) of K. pneumoniae. Resistance to at least three classes of antimicrobials was detected in ۳۰ (۶۱.۲%) PMABL producers. Among AmpC producers, ۳۴ isolates harbored only one AmpC gene group, including MOX (n=۱۱), EBC (n=۸), ACC (n=۷), CIT (n=۴), FOX (n=۲), and DHA (n=۲). Multiple AmpC gene groups were detected in ۱۵ isolates. The ERIC-PCR showed the polyclonal distribution of AmpC-producing isolates. Conclusion: In our study, a high frequency of AmpC-producing K. pneumoniae was observed. This is the first report of ACC type AmpC beta-lactamase in Iran. Strategies to minimize the spread of AmpC beta-lactamase-producing isolates should be implemented.

کلیدواژه ها:

Klebsiella pneumoniae ، AmpC beta-lactamases ، Urinary tract infections