engleski

Epidemiology of colistin-resistant, carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii in Croatia

Colistin is a last-resort antibiotic for the treatment of infections caused by multidrug and carbapenem-resistant Gram-negative bacteria. Colistin resistance has been emerging and multiple outbreaks have been reported in Europe. It has been mostly reported in carbapenem-resistant K. pneumoniae. In this study, 24 multidrug and colistin-resistant clinical isolates (14 K. pneumoniae, one E. aerogenes, one E. cloacae, and eight A. baumannii) were collected from 4 hospitals in Croatia from 2013 to 2018, to describe the epidemiology and mechanisms of antibiotic resistance. β-lactamase and carbapenemase genes were detected by PCR. Genotyping was done with rep-PCR. Whole genome sequencing was performed to discover possible molecular mechanisms for the observed colistin resistance. All isolates, except one, were extensively drug resistant. Ten out of 16 (63%) K. pneumoniae isolates possessed blaOXA-48, which is the most common carbapenem resistance gene in Croatia and elsewhere in Europe. All A. baumanni isolates possessed OXA-23-like carbapenem hydrolyzing oxacillinase. Colistin resistance was most likely chromosomally mediated. After sequence analysis, none of the isolates were found to possess any of the mcr gene variants. Several previously reported amino acid changes were found in PmrB, PhoP, PhoQ, MgrB, and LpxC, which are associated with colistin resistance. Most importantly, the presence of colistin resistance together with carbapenemase genes in extensively drug resistant isolates poses real threats in the use of carbapenems and colistin to fight infections.

Acinetobacter baumannii ; carbapenems ; carbapenem-hydrolyzing oxacillinase ; resistance ; klebsiella pneumoniae ; colistin resistance

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