Screening of Class 1 and Class 2 Integrons in Clinical Isolates of Pseudomonas aeruginosa Collected from Seven Hospitals in Turkey: A Multicenter Study

Pseudomonas aeruginosa is one of the leading nosocomial pathogens worldwide, and their infections are difficult to treat due to acquired resistance to many antibiotics. This study aimed to detect class 1 and 2 integrons and antibiotic susceptibility of clinical isolates of P. aeruginosa. Two hundred and five P. aeruginosa strains were collected from the seven general state hospitals in Turkey. They were characterized by antimicrobial susceptibility testing, screened for class 1 and class 2 integrons, and evaluated for the association between antibiotic resistance phenotypes and the presence of integrons. intI gene was amplified in 10 isolates (4.87%) by PCR and in seven isolates of them (70%) were found different gene cassettes. The aadA gene integrated into the class 1 integrons was most frequently found and it was followed by aac genes and blaOXA family genes. Sequence analysis of variable regions of the class 1 integrons showed five gene cassette arrays; aadA1(99%), aac(3)-Id(82%)-orf-aac(3”)-Ia(99%), aac(3)-Ie(83%)-blaoxa10(100%)- aadA1 (100%), aadA6(99%, 100%), aac(6’)-I(97%)-orf-aadA2(99%). No class 2 integron was detected. This study is the first multicenter study for class 1 integrons and it indicates the low rate of presence of class 1 gene cassette in P. aeruginosa.