Rashvand P, Peymani A, Mohammadi M, Karami A A, Samimi R, Hajian S, Porasgari D, Habibollah-Pourzereshki N
Student Research Committee, Qazvin University of Medical Sciences, Qazvin, Iran.
Medical Microbiology Research Centre, Qazvin University of Medical Sciences, Qazvin, Iran.
New Microbes New Infect. 2021 Apr 23;42:100883. doi: 10.1016/j.nmni.2021.100883. eCollection 2021 Jul.
Aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methylases (16S RMTase) are two main resistance mechanisms against aminoglycosides. This study aimed to evaluate the frequency of AMEs and 16S rRNA methylase genes among aminoglycoside non-susceptible isolates and to assess their clonal relationship using repetitive extragenic palindromic-PCR (rep-PCR). In this cross-sectional study, a total of 192 isolates were collected from the patients hospitalized in Qazvin, Iran (January 2016 to January 2018). Identification of isolates was performed by standard laboratory methods and API 20E strips. Antimicrobial susceptibility was determined by Kirby-Bauer method followed by examination of the genes encoding the AMEs and 16S RMTase by PCR and sequencing methods. The clonal relationship of isolates was carried out by rep-PCR. In total, 98.4% of isolates were non-susceptible to aminoglycosides, 98.4%, 97.9% and 83.9% of isolates were found to be non-susceptible against gentamicin, tobramycin and amikacin, respectively. The frequencies of , , , and genes were 59.3%, 39.2%, 39.2%, 31.7% and 69.8%, respectively, either alone or in combination. Rep-PCR results showed that the aminoglycoside nonsusceptible isolates belonged to three distinct clones: A (79.4%), B (17.5%) and C (3.2%). The findings of this study showed a high frequency for AMEs with the emergence of genes among the aminoglycoside non-susceptible isolates. Rational administration of aminoglycosides as well as using an appropriate infection control policy may reduce the presence of resistance to antibiotics in medical centres.
氨基糖苷类修饰酶（AMEs）和16S rRNA甲基化酶（16S RMTase）是对氨基糖苷类产生耐药性的两种主要机制。本研究旨在评估氨基糖苷类不敏感菌株中AMEs和16S rRNA甲基化酶基因的频率，并使用重复基因外回文序列PCR（rep-PCR）评估它们的克隆关系。在这项横断面研究中，共从伊朗加兹温住院患者中收集了192株菌株（2016年1月至2018年1月）。通过标准实验室方法和API 20E试条对菌株进行鉴定。采用 Kirby-Bauer 法测定抗菌药物敏感性，随后通过PCR和测序方法检测编码AMEs和16S RMTase的基因。通过rep-PCR分析菌株的克隆关系。总体而言，98.4%的菌株对氨基糖苷类不敏感，分别有98.4%、97.9%和83.9%的菌株对庆大霉素、妥布霉素和阿米卡星不敏感。单独或联合存在时，aac(6’)-Ie-aph(2”)-Ia、ant(3”)-Ia、ant(2”)-Ia、aac(3)-IIa和rmtB基因的频率分别为59.3%、39.2%、39.2%、31.7%和69.8%。rep-PCR结果显示，氨基糖苷类不敏感菌株属于三个不同的克隆：A（79.4%）、B（17.5%）和C（3.2%）。本研究结果表明，在氨基糖苷类不敏感菌株中，AMEs出现频率较高，且出现了rmtB基因。合理使用氨基糖苷类药物以及采用适当的感染控制策略可能会降低医疗中心抗生素耐药性的存在。
