Identification of PER-1 extended-spectrum beta-lactamase producing Pseudomonas aeruginosa clinical isolates of the international clonal complex CC11 from Hungary and Serbia.

PER-1 extended-spectrum beta-lactamase-producing Pseudomonas aeruginosa clinical isolates from Budapest, Hungary, and Belgrade, Serbia, were characterized by molecular methods. Two PER-1-positive isolates were recovered from sporadic cases in Budapest and a small cluster of PER-1-positive infections involving four patients were identified at a Belgrade hospital. A class 1 integron harbouring a bla(OXA-2)beta-lactamase gene and four other gene cassettes was detected in both the Budapest and the Belgrade isolates. The two P. aeruginosa isolates from Budapest also carried another class 1 integron containing bla(OXA-74), aac(6')-Ib-cr and cmlA7 genes in its variable region. The aac(6')-Ib-cr fluoroquinolone-acetylating aminoglycoside acetyltransferase gene is described here for the first time in P. aeruginosa. Multilocus sequence typing (MLST) revealed that the PER-1 positive P. aeruginosa isolates identified in this study display ST235, a sequence type that belongs to clonal complex CC11. Two bla(PER-1)-positive P. aeruginosa reference isolates from France and Belgium could also be assigned to complex CC11 by MLST. Our results underscore the role of complex CC11 in the dissemination of bla(PER-1) among P. aeruginosa clinical isolates.