The Role of aac(6)-IIa and ant(2'')-Ia Genes and the Presence of Class 1 Integrons in Resistance of Pseudomonas Aeruginosa Clinical Isolates against Aminoglycosides

The aminoglycoside modifying enzymes (AMEs) and class 1 integrons in clinical isolates of pseudomonas aeruginosa are the major factors leading to rapid spread of antibiotic resistance. The aim of the present study was to investigate the frequency of aac(6)-IIa, ant(2'')-Ia, and class 1 integrons in clinical isolates of pseudomonas aeruginosa.

For this descriptive-analytic study (2017-2018), 100 clinical isolates of pseudomonas aeruginosa were collected from Sari teaching hospitals and identified by differential diagnostic tests. Antibiotic susceptibility pattern of all isolates against selected antibiotics was evaluated using standard disk agar diffusion method. Subsequently, all isolates were evaluated for the presence of aac (6) -IIa, ant (2'') -Ia genes, and class I integrons using PCR method.

Out of 100 pseudomonas aeruginosa clinical isolates, 28%, 42%, and 39% were resistant to amikacin, gentamicin, and tobramycin, respectively, while 26 isolates were resistant to all three antibiotics. The results of PCR showed that 42% of the clinical isolates contained class 1 integrons. The prevalence of aac (6) -IIa and ant (2 '') - Ia genes in aminoglycoside resistant isolates was 41.8% and 13.9%, respectively.

Aminoglycosides are the preferred drug for the combined treatment of infections caused by Pseudomonas aeruginosa and the prevalence of resistance to them is also high, so the intermittent examination of the susceptibility pattern of these antibiotics and the genes associated with this issue is necessary to prevent the prevalence of high levels of resistance in this bacterium.