Khuntayaporn Piyatip, Kanathum Pohnvipa, Houngsaitong Jantana, Montakantikul Preecha, Thirapanmethee Krit, Chomnawang Mullika Traidej
Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand.
Department of Pharmacy, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand.
Ann Clin Microbiol Antimicrob. 2021 Mar 20;20(1):19. doi: 10.1186/s12941-021-00424-z.
Acinetobacter baumannii has emerged as one of the common multidrug resistance pathogens causing hospital-acquired infections. This study was conducted to elucidate the distribution of antimicrobial resistance genes in the bacterial population in Thailand. Multidrug-resistant A. baumannii (MDR A. baumannii) isolates were characterized phenotypically, and the molecular epidemiology of clinical isolates in 11 tertiary hospitals was investigated at a country-wide level.
A total of 135 nonrepetitive MDR A. baumannii isolates collected from tertiary care hospitals across 5 regions of Thailand were examined for antibiotic susceptibility, resistance genes, and sequence types. Multilocus sequence typing (MLST) was performed to characterize the spread of regional lineages.
ST2 belonging to IC2 was the most dominant sequence type in Thailand (65.19%), and to a lesser extent, there was also evidence of the spread of ST164 (10.37%), ST129 (3.70%), ST16 (2.96%), ST98 (2.96%), ST25 (2.96%), ST215 (2.22%), ST338 (1.48%), and ST745 (1.48%). The novel sequence types ST1551, ST1552, ST1553, and ST1557 were also identified in this study. Among these, the blaoxa-23 gene was by far the most widespread in MDR A. baumannii, while the blaoxa-24/40 and blaoxa-58 genes appeared to be less dominant in this region. The results demonstrated that the predominant class D carbapenemase was blaOXA-23, followed by the class B carbapenemase blaNDM-like, while the mcr-1 gene was not observed in any isolate. Most of the MDR A. baumannii isolates were resistant to ceftazidime (99.23%), gentamicin (91.85%), amikacin (82.96%), and ciprofloxacin (97.78%), while all of them were resistant to carbapenems. The results suggested that colistin could still be effective against MDR A. baumannii in this region.
This is the first molecular epidemiological analysis of MDR A. baumannii clinical isolates at the national level in Thailand to date. Studies on the clonal relatedness of MDR A. baumannii isolates could generate useful data to understand the local epidemiology and international comparisons of nosocomial outbreaks.
鲍曼不动杆菌已成为引起医院获得性感染的常见多重耐药病原体之一。本研究旨在阐明泰国细菌群体中抗菌药物耐药基因的分布情况。对多重耐药鲍曼不动杆菌（MDR A.baumannii）分离株进行表型特征分析，并在全国范围内调查11家三级医院临床分离株的分子流行病学。
从泰国5个地区的三级护理医院收集了135株非重复的MDR A.baumannii分离株，检测其抗生素敏感性、耐药基因和序列类型。采用多位点序列分型（MLST）来描述区域谱系的传播情况。
属于IC2的ST2是泰国最主要的序列类型（65.19%），在较小程度上，也有证据表明ST164（10.37%）、ST129（3.70%）、ST16（2.96%）、ST98（2.96%）、ST25（2.96%）、ST215（2.22%）、ST338（1.48%）和ST745（1.48%）的传播。本研究还鉴定出了新的序列类型ST1551、ST1552、ST1553和ST1557。其中，blaoxa - 23基因在MDR A.baumannii中是迄今为止分布最广的，而blaoxa - 24/40和blaoxa - 58基因在该地区似乎不那么占主导地位。结果表明，主要的D类碳青霉烯酶是blaOXA - 23，其次是B类碳青霉烯酶blaNDM样，而在任何分离株中均未观察到mcr - 1基因。大多数MDR A.baumannii分离株对头孢他啶（99.23%）、庆大霉素（91.85%）、阿米卡星（82.96%）和环丙沙星（97.78%）耐药，而它们对碳青霉烯类均耐药。结果表明，黏菌素在该地区对MDR A.baumannii可能仍然有效。
这是迄今为止泰国全国范围内对MDR A.baumannii临床分离株进行的首次分子流行病学分析。对MDR A.baumannii分离株的克隆相关性研究可为了解当地流行病学和医院感染暴发的国际比较提供有用数据。
