Molecular characterization of carbapenem resistance and hypervirulence determinants of Klebsiella pneumoniae circulating in a tertiary hospital in Cyprus.

BACKGROUND

The emergence of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) has become a major global public health concern. Infections caused by CR-Kp strains that also possess hypervirulence traits present significant challenges for clinical management and are associated with increased morbidity and mortality. This study aimed to investigate the prevalence of β-lactamase genes and hypervirulence-associated markers among clinical CR-Kp isolates collected in Cyprus.

METHODS

A total of 96 K. pneumoniae isolates were investigated. Species-level identification and antimicrobial susceptibility testing were performed using the VITEK-2 system. Carbapenem resistance was assessed using the Modified Hodge test (MHT). Hypermucoviscous phenotype was determined by string test. The presence of carbapenemase genes (blaOXA-48, blaNDM, blaIMP, and blaVIM) and hypervirulence-associated genes (iucA, peg-344 and iroB) were investigated by conventional polymerase chain reaction.

RESULTS

Among isolates, 75 (78.1%) were identified as CR-Kp by the MHT test. Among CR-Kp isolates, 84.0% (63/75) were positive for blaOXA-48, 8.0% (6/75) for blaIMP, 4.0% (3/75) for blaVIM, and 2.7% (2/75) for blaNDM. Co-existence of carbapenemases (blaOXA-48/blaNDM, blaOXA-48/blaIMP, blaOXA-48/blaVIM) was also observed in eight isolates. Based on string test, 32 (42.7%) of the CR-Kp isolates exhibited a hypermucoviscous phenotype. Aerobactin synthesis gene iucA was detected in 44 (58.7%) isolates, whereas the metabolic transporter gene peg-344 and iroB gene were not found in any of the examined isolates.

CONCLUSIONS

This is the first report describing CR-Kp isolates with hypervirulence-associated characteristics in Cyprus. The emergence of these convergent strains in the region highlights the need for continuous molecular surveillance and stringent infection control measures in order to avert their future dissemination in the healthcare environment.