VIM-1, VIM-2, and GES-5 Carbapenemases Among Pseudomonas aeruginosa Isolates at a Tertiary Hospital in Istanbul, Turkey

Worldwide increase in carbapenem resistance and transferable carbapenemases are significant challenges in treatment of Pseudomonas aeruginosa infections. In this study, investigation of carbapenemase production in carbapenem-resistant P. aeruginosa isolates recovered from clinical specimens in a tertiary hospital was aimed. A total of 84 carbapenem-resistant P. aeruginosa isolates were examined. "Carbapenem inactivation method" (CIM) was used for phenotypic detection of carbapenemase production. The existence of bla_KPC, bla_NDM, bla_IMP, bla_VIM, bla_OXA-48, and bla_GES genes was investigated by polymerase chain reaction (PCR). Subtypes of the detected genes were identified by sequence analysis. Arbitrarily primed PCR (AP-PCR) was performed to evaluate the clonal relationship among the isolates. The presence of high-risk clones in carbapenemase producers was investigated by Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Three isolates (3.5%) were identified as carbapenemase producers by CIM tests, while PCR tests demonstrated three isolates carrying carbapenemase genes as well. bla_VIM gene was found in two isolates and bla_GES gene was found in one isolate. Sequence analysis demonstrated that the carbapenemases were VIM-1, VIM-2, and GES-5. AP-PCR yielded high clonal diversity among the isolates. According to MALDI-TOF MS analysis, none of the carbapenemase-producing strains belonged to the high-risk clones. In conclusion, the presence of VIM-1, VIM-2, and GES-5 type carbapenemases in P. aeruginosa isolates was demonstrated for the first time in our hospital, GES-5 being reported for the second time in Turkey. Our results will lead strategies for controlling the spread of carbapenemases and contribute to epidemiological data from Turkey.