Integrons, β‐lactamase and
genes in multidrug resistant clinical isolates of qnr Proteus mirabilis and P. vulgaris
Abstract:Thirty‐three isolates of Proteus mirabilis and two P. vulgaris were examined for their antimicrobial resistance, the presence of integrons with regard to gene cassette content, and genetic determinants of β‐lactam and low‐level quinolone resistance. Integrons were detected in 23 (69.7%) P. mirabilis isolates; six (18.2%) of them had class 1 integrons, 11 (33.3%) possessed class 2 integrons and six (18.2%) carried integrons of both classes. One P. vulgaris strain possessed class 1 and class 2 integrons. The presence of integrons was associated with increased frequency of resistance to gentamicin, ciprofloxacin, sulfamethoxazole and co‐trimoxazole. Moreover, integron presence was associated with increased resistance range in terms of both the number of antimicrobials and the number of classes of antimicrobials to which a strain was resistant. Class 1 integrons contained aadA1, aadB‐aadA1, dfrA1‐aadA1, bla PSE‐1‐aadA1 and aacA4‐orfA‐orfB‐aadA1 gene cassette arrays, whereas all class 2 integrons had a dfrA1‐sat2‐aada1 array. β‐lactamase genes not associated with integrons comprised bla TEM‐2, bla DHA‐1 and bla CMY‐15. Plasmid‐mediated fluoroquinolone resistance was determined by qnrD and qnrS1 genes. This is the first report of P. vulgaris strains harbouring qnrD genes in Europe.
Document Type: Research Article
Publication date: December 1, 2012