Investigation of bla(OXA-48)-Like Genes in Carbapenemase Producing Klebsiella spp. Isolates

Abstract

The emergence and spread of multi-drug-resistant (MDR), extended-spectrum beta-lactamase (ESBL) producing carbapenem-resistant members of Enterobacteriaceae family has become a worldwide health problem. Carbapenem resistance caused by bla(KPC), bla(NDM) gene regions are sporadic and bla(OXA-48) gene region is endemic in our country. The aim of this study was to determine the presence of bla(OXA-232), bla(OXA-181), bla(OXA-162), bla(OXA-204), bla(OXA-244), bla(OXA-163), bla(OXA-245) genes in OXA-48 like carbapenemase producing Klebsiella pneumoniae isolates. The isolates used in this study were provided from the Medical Microbiology Laboratory collection of Sakarya University Sakarya Training and Research Hospital. Identification and antibiotic susceptibility tests were determined by the VITEK 2 (R) automated system (biomerieux, France) and the carbapenemase production of isolates was determined by the modified Hodge test. Minimal inhibitor concentration (MIC) values were determined with broth microdilution method. The isolates containing the bla(OXA-48)-like gene region were identified by real-time polymerase chain reaction (Rt-PCR) method using consensus primers. In "High Resolution Melting Analysis (HRMA)" method carried out by using "Type-it HRM PCR" (Qiagen, Hilden, Germany) kit, isolates which showed a deviation in melting temperatures (Tm) were selected with the suspicion of OXA-48 variant. The sequence analysis (ABI 3500, Applied Biosystems, USA) was carried out to determine which variants were present in these isolates. Compatibility of MIC values was determined between VITEK 2 (R) and the microdilution method with the rate of 82% for imipenem, 77% for meropenem and 90% for ertapenem in carbapenemase-producing K. pneumoniae isolates. In 45 of 100 K. pneumoniae isolates, the bla(OXA-48)-like gene region was found to be positive by the Rt-PCR method. For the determination of OXA-48 variants, these 45 isolates were evaluated by HRMA method. The sequence analysis revealed that 41 (91.2%) isolates contained bla(OXA-48)/bla(OXA-245) gene regions, while 2 (4.4%) isolates were found to contain bla(OXA-181) gene regions and 2 (4.4%) isolates were found to contain bla(OXA-244) gene regions. This is the first study to determine OXA-48 and OXA-244 positivity in bla(OXA-48)-like gene regions in Turkey. As a result of this study, the OXA-48-like gene region was found to be 45%, of which 4.4% had bla(OXA-181) and 4.4% had bla(OXA-244) gene regions. The detection of bla(OXA-48)-like gene regions will guide for the selection of antibiotics in critical patient groups.