Research Article Role of Aminoglycoside-Modifying Enzymes (AMEs) in Resistance to Aminoglycosides among Clinical Isolates of Pseudomonas aeruginosa in the North of Iran Leila Ahmadian , 1,2 Zahra Norouzi Bazgir , 2,3 Mohammad Ahanjan , 1,2 Reza Valadan , 1,4 and Hamid Reza Goli 1,2 1 Molecular and Cell Biology Research Centre, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 2 Department of Medical Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 3 Student Research Committee, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran 4 Department of Immunology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Correspondence should be addressed to Hamid Reza Goli; goli59@gmail.com Received 4 July 2021; Accepted 7 August 2021; Published 23 August 2021 Academic Editor: Stefania Cantore Copyright © 2021 Leila Ahmadian et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In recent years, the prevalence of resistance to aminoglycosides among clinical isolates of Pseudomonas aeruginosa is increasing. The aim of this study was to investigate the role of aminoglycoside-modifying enzymes (AMEs) in resistance to aminoglycosides in clinical isolates of P. aeruginosa. The clinical isolates were collected from different hospitals. Disk agar diffusion test was used to determine the antimicrobial resistance pattern of the clinical isolates, and the minimum inhibitory concentration of aminoglycosides was detected by microbroth dilution method. The PCR was performed for discovery of aminoglycoside- modifying enzyme-encoding genes. Among 100 screened isolates, 43 (43%) isolates were resistant to at least one tested aminoglycosides. However, 13 (13%) isolates were resistant to all tested aminoglycosides and 37 isolates were detected as multidrug resistant (MDR). The resistance rates of P. aeruginosa isolates against tested antibiotics were as follows: ciprofloxacin (41%), piperacillin-tazobactam (12%), cefepime (32%), piperacillin (26%), and imipenem (31%). However, according to the MIC method, 13%, 32%, 33%, and 37% of the isolates were resistant to amikacin, gentamicin, tobramycin, and netilmicin, respectively. The PCR results showed that AAC(6 ′ )-Ib was the most commonly (26/43, 60.4%) identified AME-encoding gene followed by AAC(6 ′ )-IIa (41.86%), APH(3 ′ )-IIb (34.8%), ANT(3 ″ )-Ia (18.6), ANT(2 ″ )-Ia (13.95%), and APH(3 ″ )-Ib (2.32%). However, APH(3 ′ )-Ib was not found in any of the studied isolates. The high prevalence of AME- encoding genes among aminoglycoside-resistant P. aeruginosa isolates in this area indicated the important role of AMEs in resistance to these antibiotics similar to most studies worldwide. Due to the transmission possibility of these genes between the Gram-negative bacteria, we need to control the prescription of aminoglycosides in hospitals. 1. Introduction Pseudomonas aeruginosa, as an opportunist pathogen, is responsible for several nosocomial infections such as bacter- emia; urinary tract, blood, respiratory, burn, and soft tissue infections; external otitis; and endocarditis in clinical set- tings, which are often difficult to treat [1, 2]. Aminoglyco- sides, fluoroquinolones, and β-lactams are clinically effective antibiotics in the treatment of infections caused by P. aeruginosa, while carbapenems are the last-line option before colistin [3–5]. Increasing resistance to fluoroquino- lones and β-lactams has led to attentiveness in clinical appli- cations of aminoglycosides against Gram-negative bacteria [6]. However, P. aeruginosa can survive in hospital environ- ments for a long time due to the high-level resistance against biocides and can acquire and/or spread the antibiotic Hindawi BioMed Research International Volume 2021, Article ID 7077344, 10 pages https://doi.org/10.1155/2021/7077344