Background: The emergence of carbapenem-resistant Klebsiella pneumoniae has become a major problem among healthcare-associated infections with relatively few therapeutic options. In particular, the infection of carbapen-emase-producing Enterobacteriaceae (CPE) can be related to the widespread nosocomial transmission. In this study, we isolated carbapenem-resistant K. pneumoniae producing carbapenemase from a tertiary-care hospital and investigated the antimicrobial resistance and molecular and epidemiological features of these isolates.
Methods: A total of 16 carbapenemase-producing K. pneumoniae strains were isolated from a tertiary-care hospital. Antimicrobial susceptibility tests were performed. Carbapenemase production was assessed using the phenotypic and genotypic tests. Molecular characteristics were determined using polymerase chain reaction to detect blaKPC, blaIMP-1, blaVIM, blaNDM, blaOXA48, and blaGES. For phylogenetic analyses, multilocus sequence typing (MLST) was performed.
Results: All of the isolates were found to be resistant to ertapenem (MIC range 2.0 - 8.0 g/mL), among which only two (12.5%) isolates were susceptible to imipenem. All isolates were resistant to ampicillin, azithromycin, cefazolin, cefepime, cefotaxime, cefoxitin, ceftazidime, and ciprofloxacin. Three isolates (18.8%) were resistant to gentamicin, and two isolates (12.5%) were resistant to amikacin. Only two isolates were identified as carbapenemase producers using the phenotypic tests. All isolates produced GES-5 carbapenemases. MLST analysis revealed four sequence types (STs): ST11 (n = 12), ST789 (n = 2), ST392 (n = 1), and an unidentified ST (n = 1).
Conclusions: ST11 K. pneumoniae producing GES-5 carbapenemase was the most common sequence type. Systematic and broad range screening tests in the early stages are required to identify the carbapenemase producers, which may help to prevent healthcare-associated transmission.