Frequency of Aminoglycoside Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa from Sistan, Iran

Introduction: Pseudomonas aeruginosa is a prevalent healthcare-acquired infection. It is a global concern due to its potential for multidrug resistance and for posing significant challenges to healthcare providers. Two critical processes that lead to aminoglycoside resistance are the methylation of 16S ribosomal RNA (16S rRNA) and aminoglycoside-modifying enzymes (AMEs). Aminoglycosides are potent antimicrobial medicines often used to eliminate pseudomonas infections efficiently. This research aimed to assess the frequency of the occurrence of 16S rRNA methylase and AME genes in clinical isolates of P. aeruginosa in Sistan, Iran. Methods: A total of 60 clinical isolates of P. aeruginosa were collected. The isolates were identified from July 1, 2020, to May 28, 2022. A multiplex polymerase chain reaction (PCR) was carried out to amplify the 16S rRNA methylase genes (armA and rmtA) and AME genes [Aph(3′)- Ib, Aph(6′)-VI, aadA1, aadB, and aac] in clinical isolates of P. aeruginosa in Sistan, Iran. Results: The most prevalent AME gene was aadB, which was present in 48.33% of the isolates (29/60). The least prevalent genes were aac, aadA1, and Aph(3′)-Ib with frequencies of 6 (10%), 6 (10%), and 7 (11.66%), respectively. It was found that 85% (51/60) of the P. aeruginosa isolated were resistant to gentamicin, 65% (39/60) were resistant to amikacin, and 23.33% (14/60) were resistant to tobramycin. Conclusion: Overall, this study determined that aadB was the most prevalent AME gene. In contrast, the genes aac, aadA1, and Aph(3′)-Ib had the lowest occurrence in clinical isolates of P. aeruginosa from southeastern Iran.