Investigation of carbapenem resistance and responsible enzymes in escherichia coli and klebsiella pneumoniae isolates

Carbapenems have an important role in thetreatment of infections caused by Gram-negative bacteria with multiple drug resistance. However, with the emergence of enzymes that hydrolyze carbapenems cause decrease of the antimicrobial activity of carbapenems recently. Carbapenemases are beta-lactamases with the strongest hydrolytic activity. For the Enterobacteriaceae family carbapenemases like OXA-48, OXA-58, KPC and beta-lactamases such as IMP, NDM, VIM are mostly responsible for carbapenem resistance. In the study, it was aimed to investigate the carbapenemase gene regions of two the most frequently isolated infection agent of Enterobacteriaceae family. The study was carried out between January and December 2017 at Afyon Kocatepe University Hospital. During the study period, 264 Enterobacteriaceae strains including 207 Klebsiella pneumoniae and 57 Escherichia coli which were isolated from various clinical specimens included in the study. Genetic regions of clinical isolates responsible showing resistance or reduced susceptibility to any of the carbapenems have been investigated. Bacterial identification and antimicrobial susceptibility testing was carried out with conventional and otomated systems (Vitek 2, bioMerieux, USA). Gene regions coding for carbapenemases such as IMP, NDM, OXA-58, OXA-48, KPC and VIM have been investigated using the polymerase chain reaction method (PCR). Most of the strains isolated from anesthesi aintensive care unit and hospitalised surgical medicine unit patient and sample like urine (47,3 %), blood (19,3 %), wound (11,7 %), tracheal aspirate (10,6 %), sputum (6,8 %) and other samples (4,3%). In 43 % of isolates (102 K. pneumoniae, 12 E. coli) were detected at least one resistance or decreased susceptibility from imipenem, ertapenem and meropenem. In 88 % of carbapenem resistant isolates, the presence of at least one of the genes encoding carbapenemase was detected. OXA-48 was most frequently observed in carbapenemase-encoding genes (63 K. pneumoniae, 5 E. coli). Other following genes were identified as IMP (12 K. pneumoniae) and VIM (45 K. pneumoniae), NDM-1 (27 K. pneumoniae). No KPC and OXA-58 genes were detected in any of the 264 Enterobacteriaceae strains. The global spread of carbapenemase-producing Enterobacteriaceae constitutes an important health problem on a universal scale due to the very limited treatment options available for infections with these strains. The results of this study show that carbapenem resistance is higher in K. Pneumoniae strains and that the primary enzyme responsible for carbapenem resistance is OXA-48 but is found frequently in metallo-beta-lactamases.