Characterization of carbapenem-resistant Escherichia coli and Klebsiella: a role for AmpC-producing isolates

Aim: This study aimed to investigate the role of AmpC enzymes in carbapenem resistance among AmpC/extended-spectrum ss-lactamase (ESBL)-producing clinical isolates of Escherichia coli and Klebsiella spp. Methods: Fifty-six bacterial strains that were AmpC producers were examined. The antibiotic susceptibility test was performed by the disk diffusion and E-test. The prevalence of the plasmid carbapenemase was determined using PCR. Results: The resistance to meropenem in the AmpC(+)/ESBL+ group was 64%, higher than that reported for the AmpC(-)/ESBL+ group. Ten isolates of the carbapenemresistant AmpC producers were negative for carbapenemase-encoding genes. Conclusion: Carbapenem resistance among AmpC-producing isolates with negative results for carbapenemase-encoding genes potentially demonstrates the role of AmpC enzymes among these isolates.

Automated summary

The study investigated the role of AmpC enzymes in carbapenem resistance among clinical isolates of Escherichia coli and Klebsiella spp. producing AmpC/extended-spectrum ss-lactamases. Fifty-six AmpC-producing bacterial strains were examined, and antibiotic susceptibility tests were performed. The results showed that carbapenem resistance was present in AmpC-producing isolates with negative results for carbapenemase-encoding genes, highlighting the potential role of AmpC enzymes.