Background: The determination of clonal interactions between microorganisms is very important in epidemiological studies. In the present study, we aimed to evaluate the resistance mechanisms and genetic relationships of carbapenem and colistin resistant Klebsiella pneumoniae (K. pneumoniae) strains isolated from inpatients at two university hospitals in Turkey.
Methods: A total of 38 K. pneumoniae clinical isolates were included in the study. Identification of isolates was confirmed by 16S rRNA sequencing. Antimicrobial susceptibility testing was performed with VITEK-2 system (bio-Mérieux, France). Modified Hodge test was used for the detection of carbapenemase activity in isolates. Carbapenem resistance genes (blaOXA-48, blaNDM, blaKPC, blaIMP, blaVIM) and colistin resistance genes (mcr-1, mcr-2 and mcr-3) were investigated by PCR. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and multilocus sequence typing (MLST) analysis were used to determine the genetic relatedness among the isolates.
Results: We detected that 58% of isolates were positive for only blaOXA-48, 5% were only positive for blaNDM, and 34% were positive for both blaOXA-48 and blaNDM. blaKPC, blaIMP, blaVIM, mcr-1, mcr-2, and mcr-3 were not detected among the isolates. Only one carbapenem resistant isolate was negative for the carbapenemase genes tested. A total of nine profiles were found by ERIC-PCR, and MLST results showed seven different sequence types-ST14, ST16, ST79, ST101, ST1543, ST2096, and ST2832. The seven STs were grouped by PHYLOVIZ Online into four clonal complexes. The most common ST was ST14 (81%) in Center 1 and ST2096 (94%) in Center 2.
Conclusions: We determined MLST types of carbapenem and colistin resistant K. pneumoniae isolates from two different centers. Although the most common ST types were different in these centers, both ST types were clustered in CC14. To the best of our knowledge this is the first report of ST14 and ST2096 outbreaks in Turkey.