采用多位点序列分型方案对不同来源的耐碳青霉烯鲍曼不动杆菌进行的系统进化分析。
Phylogenetic analysis of carbapenem-resistant Acinetobacter baumannii isolated from different sources using Multilocus Sequence Typing Scheme.
机构信息
Water Research Institute, Council for Scientific and Industrial Research-CSIR-Ghana, P. O. Box M 32. Accra Ghana 2nd CSIR Close, Accra, Ghana.
Division of Medical Microbiology, Department of Laboratory Medicine & Pathology, Faculty of Health Sciences, Walter Sisulu University, Private Bag: X1, Mthatha - 5117 Eastern Cape Province, South Africa; Division of Medical Microbiology, National Health Laboratory Services (NHLS), Nelson Mandela Central Hospital, Mthatha 5100, South Africa..
出版信息
Infect Genet Evol. 2021 Dec;96:105132. doi: 10.1016/j.meegid.2021.105132. Epub 2021 Nov 12.
The emergence and worldwide distribution of carbapenem-resistant Acinetobacter baumannii strains has become a major public health threat. The objective of this study was to investigate the clonal relatedness of A. baumannii isolates collected from clinical and extra-hospital environments in Mthatha, South Africa. Forty carbapenem-resistant isolates comprising of clinical (20) and extra-hospital (20) were identified and tested for antimicrobial susceptibility. Detection of carbapenemase encoding genes was performed by Real-time PCR. The clonal relationship of clinical isolates relative to extra-hospital isolates was determined via multilocus sequence typing (MLST). All isolates (clinical and extra-hospital) were resistant to most common antibiotics including carbapenems (imipenem; MIC ≥32 μg/mL and meropenem; MIC ≥32 μg/mL) with the only exception being amikacin (with 3 isolates susceptible), tigecycline (14 isolates susceptible) and colistin (all isolates susceptible). The bla OXA-23-like and the intrinsic bla OXA-51 -like genes were detected in all the isolates tested. The bla OXA-58-like and bla IMP-type genes were detected in 2 clinical isolates whilst the bla OXA-24-like, bla VIM-type, bla NDM-1, bla SIM, and bla AmpC were not detected. The bla OXA-24-like, bla OXA-58-like, bla IMP-type, bla VIM-type, bla NDM-1, bla SIM, and bla AmpC were negative in the extra-hospital isolates. Co-occurrence of bla OXA-23 -like, bla OXA-58-like and bla IMP-type was observed in 2 clinical isolates. The MLST performed on 33 isolates identified 5 existing sequence types (ST) (ST1, ST2, ST25, ST85 and ST215) in clinical isolates and 2 existing STs (ST1 and ST2) in extra-hospital isolates. The most dominant ST was ST2 accounting for 68.8% of the clinical isolates and 82.4% of the extra-hospital isolates. The study demonstrated high prevalence and potential clonal spread of globally-disseminated clonal complex 2 carrying bla OXA-23-like within our local settings. However, ST25 might be an emerging lineage carrying the bla OXA-23-like . Continuous monitoring is important in limiting the spread of these strains in other healthcare settings and the community.
碳青霉烯类耐药鲍曼不动杆菌菌株的出现和在全球范围内的分布已成为一个主要的公共卫生威胁。本研究的目的是调查南非姆塔塔临床和医院外环境中分离的鲍曼不动杆菌的克隆相关性。从临床（20 例）和医院外（20 例）环境中分离出 40 株耐碳青霉烯类鲍曼不动杆菌，并对其进行了抗菌药物敏感性检测。通过实时 PCR 检测碳青霉烯酶编码基因。通过多位点序列分型（MLST）确定临床分离株与医院外分离株的克隆关系。所有分离株（临床和医院外）对包括碳青霉烯类（亚胺培南；MIC≥32μg/ml 和美罗培南；MIC≥32μg/ml）在内的大多数常用抗生素均具有耐药性，唯一的例外是阿米卡星（3 株分离株敏感）、替加环素（14 株分离株敏感）和多粘菌素（所有分离株敏感）。在所有检测的分离株中均检测到 bla OXA-23 样和固有 bla OXA-51 样基因。bla OXA-58 样和 bla IMP 型基因在 2 株临床分离株中检出，而 bla OXA-24 样、bla VIM 型、bla NDM-1、bla SIM 和 bla AmpC 未检出。bla OXA-24 样、bla OXA-58 样、bla IMP 型、bla VIM 型、bla NDM-1、bla SIM 和 bla AmpC 在医院外分离株中均为阴性。在 2 株临床分离株中观察到 bla OXA-23 样、bla OXA-58 样和 bla IMP 型同时存在。对 33 株分离株进行 MLST 分析，在临床分离株中鉴定出 5 种现有序列型（ST）（ST1、ST2、ST25、ST85 和 ST215），在医院外分离株中鉴定出 2 种现有 ST（ST1 和 ST2）。最主要的 ST 是 ST2，占临床分离株的 68.8%，占医院外分离株的 82.4%。该研究表明，在我们当地环境中，携带 bla OXA-23 样的全球传播克隆复合体 2 具有高流行率和潜在的克隆传播。然而，ST25 可能是一种携带 bla OXA-23 样的新兴谱系。持续监测对于限制这些菌株在其他医疗机构和社区中的传播非常重要。
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