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

Abstract

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 bla OXA family genes. Sequence analysis of variable regions of the class 1 integrons showed five gene cassette arrays;

Dissemination of Class 1 Integron among Different Multidrug Resistant Pseudomonas aeruginosa Strains

“…All P. aeruginosa isolates were 100% resistant to ampicillin, cefixime, cephalothin, nalidixic (32, 33). However, the frequency of class 1 integrons was very low (4.5%) in a multicenter study in Turkey (34). The frequency of intI1 in our study was similar…”

Investigation of Antibiotic Resistance Genes and Class 1 Integron in Multi-Drug Resistant P. aeruginosa and E. coli Strains

“…The most prevalent mechanism of aminoglycoside resistance are Aad and Aac families [13,14]. In the isolates of our study, the most common resistance is the aadA family (aadA5) and the dfrA family (dfrA17).…”

“…In these studies, the frequencies of class integrons were found 41.5% (44/106) in Brazil, 60% in England, 59% in France and 52% in Taiwan [11,13]. In Turkey, in a multicenter study of clinical P. aeruginosa isolates, the frequency of class 1 integrons was found to be 4.8% [14]. Resistance genes that cause aminoglycosides and β-lactams are frequently found on integrons in Pseudomonas and Enterobacteriaceae members.…”

Prevalence of Class 1, 2, and 3 Integrons and Biofilm Formation in Pseudomonas aeruginosa and Acinetobacter baumannii among ICU and non-ICU Patients

“…The second class of integrons (Class 2) was found in transposon Tn7 and its derivatives, and its 3′ conserved segment containing five tns genes involved in the movements of the transposon, which have been reported most often in isolates within the Enterobacteriaceae family (13). As compared to Class 1 and 2, less is known about Class 3 integron which have been described as rare and found only in a 2 limited number of isolates including Serratia marcescens, Klebsiella pneumoniae, P. aeruginosa, P. putida, Alcaligenes xylosoxidans, and Delftia spp (14). Cassettes usually include a single ORF and downstream, an attC site which is an imperfect inverted repeat sequence related to a 60bp consensus sequence (14)(15)(16).…”

“…As compared to Class 1 and 2, less is known about Class 3 integron which have been described as rare and found only in a 2 limited number of isolates including Serratia marcescens, Klebsiella pneumoniae, P. aeruginosa, P. putida, Alcaligenes xylosoxidans, and Delftia spp (14). Cassettes usually include a single ORF and downstream, an attC site which is an imperfect inverted repeat sequence related to a 60bp consensus sequence (14)(15)(16).…”