High Prevalence of Plasmid-Mediated Quinolone Resistance among ESBL/AmpC-Producing Enterobacterales from Free-Living Birds in Poland.

In this study, we investigated the occurrence of plasmid-mediated quinolone resistance (PMQR) in extended-spectrum β-lactamase- (ESBL) and/or AmpC-type β-lactamase-producing isolates from free-living birds in Poland. The prevalence of the gene was 63%, and the distribution of isolates in terms of bacterial species was as follows: 67% (22/33) corresponded to , 83% (5/6) to , 44% (4/9) to and 33% (1/3) to . The gene was also found in a single isolate of . The molecular characteristics of -positive isolates pointed to extended-spectrum beta lactamase CTX-M as the most prevalent one (89%) followed by TEM (47%), AmpC (37%) and SHV (16%). This study demonstrates the widespread occurrence of PMQR-positive and ESBL/AmpC-producing isolates in fecal samples from wild birds. In this work, plasmid pAM1 isolated from strain SN25556 was completely sequenced. This plasmid is 3191 nucleotides long and carries the gene, which mediates decreased susceptibility to quinolones. It shares extensive homology with other previously described small -harboring plasmids. The nucleotide sequence of pAM1 showed a variable region flanked by an oriT locus and a Xer recombination site. The presence of a putative recombination site was detected, suggesting that interplasmid recombination events might have played a role in the development of pAM1. Our results highlight the broad geographical spread of ColE-type Qnr resistance plasmids in clinical and environmental isolates of . As expected from the results of phenotypic susceptibility testing, no resistance genes other than were identified.