Cayci Yeliz Tanriverdi, Ulker Kubra Hacieminoglu, Birinci Asuman
Department of Medical Microbiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
Infez Med. 2021 Dec 10;29(4):568-573. doi: 10.53854/liim-2904-10. eCollection 2021.
Carbapenem-resistant (CRE) have become a growing problem worldwide in recent years. Options for the treatment of CRE are limited and one of these options is gentamicin. For this reason, gentamicin susceptibility should be properly determined. In a recently reported study, it is recommended to review the results of automated systems for assessing gentamicin susceptibility in carbapenem-resistant isolates. In this study, we aimed to determine gentamicin susceptibility using three different methods and compare the methods. The study included 107 CRE isolates from different samples. Gentamicin susceptibility was determined using Vitek 2 Compact (bioMérieux, France), Microscan Walkaway Plus (Beckman Coulter, USA) automatic systems, and disk diffusion (DD) method. The broth microdilution method (BMD) was used as reference method. Minor, major, and very major errors and categorical agreement rates were determined for each method. Aminoglycoside-modifying enzymes (aac(6')Ib and aph(2″)Ia) were assayed in discrepant isolates. According to BMD results, 90.7%, 1,8 %, and 7.5 % of the isolates were determined as susceptible, intermediate, and resistant to gentamicin, respectively. Compared to the results of the BMD for detecting gentamicin susceptibility, disk diffusion method showed the highest categorical agreement (98.1%), and Vitek 2 Compact showed the lowest categorical agreement (90.6%). The very major error rates were determined 7.5%, 0.9%, and 0.9% for Vitek 2 Compact, Microscan Walkaway Plus, and DD method, respectively. In addition, aac(6')Ib and aph(2″)Ia genes were detected in 8 discrepant isolates. For gentamicin susceptibility, the DD showed the most compatible results. The DD can be used as a reliable method for determining gentamicin susceptibility. Compatibility of automated systems with BMD was acceptable, although lower than DD. The discrepancies detected in the Vitek 2 Compact results could be due to the presence of aac(6')Ib and/or aph(2″)Ia aminoglycoside-modifying enzymes.
近年来，耐碳青霉烯类肠杆菌科细菌（CRE）已成为全球范围内日益严重的问题。治疗CRE的选择有限，其中之一是庆大霉素。因此，应正确测定庆大霉素敏感性。在最近报道的一项研究中，建议复查用于评估耐碳青霉烯类分离株中庆大霉素敏感性的自动化系统结果。在本研究中，我们旨在使用三种不同方法测定庆大霉素敏感性并比较这些方法。该研究纳入了来自不同样本的107株CRE分离株。使用Vitek 2 Compact（法国生物梅里埃公司）、Microscan Walkaway Plus（美国贝克曼库尔特公司）自动化系统以及纸片扩散法（DD）测定庆大霉素敏感性。肉汤微量稀释法（BMD）用作参考方法。测定了每种方法的小误差、大误差和非常大误差以及分类一致率。对结果不一致的分离株检测氨基糖苷类修饰酶（aac(6')Ib和aph(2″)Ia）。根据BMD结果，分别有90.7%、1.8%和7.5%的分离株被判定对庆大霉素敏感、中介和耐药。与检测庆大霉素敏感性的BMD结果相比，纸片扩散法显示出最高的分类一致率（98.1%），而Vitek 2 Compact显示出最低的分类一致率（90.6%）。Vitek 2 Compact、Microscan Walkaway Plus和DD法的非常大误差率分别为7.5%、0.9%和0.9%。此外，在8株结果不一致的分离株中检测到了aac(6')Ib和aph(2″)Ia基因。对于庆大霉素敏感性，DD显示出最一致的结果。DD可作为测定庆大霉素敏感性的可靠方法。自动化系统与BMD的一致性是可接受的，尽管低于DD。Vitek 2 Compact结果中检测到的差异可能是由于存在aac(6')Ib和/或aph(2″)Ia氨基糖苷类修饰酶。
