Detection of carbapenem-resistant Klebsiella pneumoniae strains harboring carbapenemase, beta-lactamase and quinolone resistance genes in intensive care unit patients.

Aim: Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) strains are important nosocomial pathogens worldwide. In this study, we aimed to reveal the antibiotic resistance of clinical CR-Kp strains and determine the presence of KPC, OXA-48, VIM and IMP carbapenemase genes. CTX-M-1, TEM-1, SHV-1 extended-spectrum beta-lactamase (ESBL) genes, qnrA, qnrB, qnrS plasmid-mediated quinolone resistance genes and sul1 and sul2 sulfonamide resistance genes provided molecular epidemiological data.

Methods

A total of 175 K. pneumoniae strains were isolated from clinical samples of patients hospitalised in an intensive care unit (ICU) betweent April and October 2017. The strains were identified with conventional methods, with VITEK 2 (BioMerieux, France) and MALDI-TOF MS (Bruker, USA). Antimicrobial susceptibilities were tested using the disc-diffusion method and E-test (BioMerieux, France). Antimicrobial resistance genes were investigated via real-time PCR in strains identified as CR-Kp.

Results

High frequencies of bla TEM-1 (86.36%), bla SHV-1 (86.36%), and bla CTX-M-1 (95.45%) genes were found in CR-Kp strains. Morever, all three ESBL genes coexisted in 77.3% of all strains. bla KPC was detected in 12 (54.55%) of the strains, and 4 of them which had an MIC> 16 μg/mL to imipenem showed bla OXA-48 positivity as well. The qnrS gene determinant (86.36%) had the highest frequency, and strains carrying qnrA showed higher MICs for ciprofloxacin.

Conclusion

CR-Kp strains are able to develop different antimicrobial resistance patterns according to regional changes in antimicrobial therapeutic policies. Thus, it is important to monitor the regional molecular epidemiological data for efficient treatment.