Occurrence of Beta-Lactamases in Colistin-Resistant Enterobacterales Strains in Poland – a Pilot Study

Sixty-five colistin-resistant Enterobacterales isolates recovered from different clinical specimens were analyzed. The strains were collected in 12 hospitals all over Poland within a period of nine months. Strains were analyzed for eight genes from the mcr family. The presence of mcr-1 gene was detected in three Escherichia coli strains. The 45/65 isolates were identified as ESBL producers. CTX-M-1-like enzymes were the most common ESBLs (n = 40). One E. coli and seven Klebsiella pneumoniae strains produced carbapenemases, with the NDM being produced by five isolates. Among all the strains tested, four and five were resistant to new drugs meropenem/vaborbactam and ceftazidime/avibactam, respectively.