Molecular Epidemiology of AmpC-Producing Klebsiella Pneumoniae Isolated from Perioperative Patients in a Tertiary Hospital

Background: Extended-spectrum cephalosporin-resistant organisms are the sources of AmpC- type β-lactamase isolates. AmpC-producing Klebsiella pneumoniae isolates are a major challenge in clinics due to their high rate of antibiotic resistance. This study aimed to detect AmpC β-lactamases in K. pneumoniae isolated from hospitalized patients with a surgical history.Materials and Methods: This cross-sectional study was performed on ۱۲۰ urine catheter samples. After antibiotic susceptibility testing, plasmid-mediated AmpC was detected by double-disc plus combined disc test (DCDT) and three-dimensional extract test (TDET). The genotypic detection of plasmid-mediated AmpC was carried out using multiplex-polymerase chain reaction (PCR).Results: Of ۱۲۰ samples, ۶۰ (۵۰%) instances of K. pneumoniae were isolated. The highest and lowest resistance rates were related to cefotaxime (CTX) (۵۰%) and ciprofloxacin (CIP) (۲۳.۳%), respectively. ۱۸.۳% (n: ۱۱) K. pneumoniae showed an AmpC phenotype in DCDT and TDET tests. AmpC genotyping showed that the prevalence of CIT, DHA, EBC, and ACC genotypes were ۴۷.۱%, ۳۵.۳%, ۲۹.۵%, and ۲۳.۶%, respectively. MOX and FOX genotypes were not identified in the isolates of interest.Conclusion: AmpC β-lactamase identification tests should be considered a routine microbiology workup for gram-negative microorganisms. Multiplex-PCR can identify the plasmid AmpC genotypes.

Keywords:

AmpC , Klebsiella pneumoniae , Double-disc plus combined test , Three-dimensional extract test