Laboratório Alerta, Division of Infectious Diseases, Department of Internal Medicine, Escola Paulista de Medicina/Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.
Laboratório Alerta, Division of Infectious Diseases, Department of Internal Medicine, Escola Paulista de Medicina/Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.
Sci Total Environ. 2020 Jul 15;726:138232. doi: 10.1016/j.scitotenv.2020.138232. Epub 2020 Mar 26.
Carbapenem resistance in Acinetobacter baumannii is a public health issue globally, mainly due to the production of carbapenem hydrolyzing class D β-lactamases (CHDLs). In Brazil, OXA-23 and OXA-143 CHDLs have been prevalent in A. baumannii from clinical settings, with some OXA-23 reports in the environmental samples, whereas OXA-72 has begun to be increasingly reported. This study aims to perform the genomic and microbiological characterization of carbapenem-resistant A. baumannii isolates recovered from migratory birds and captive birds inhabiting a lake within a Brazilian Zoo. Four hundred and eighty-one gram-negative bacilli were recovered from choanal and cloacal swabs obtained from 50 migratory birds and 37 captive birds present at the zoo's lake between July and August of 2012. Among all GNB, nine OXA-72-producing A. baumannii were detected from the microbiota of four migratory and five captive aquatic birds. The OXA-72-producing A. baumannii isolates were submitted to antimicrobial susceptibility test and PFGE, exhibiting a multidrug-resistant profile and clonal relatedness with OXA-72-positive human isolates circulating for eighteen years in a hospital setting. MLST, plasmid analysis and whole-genome sequencing revealed which all carbapenem-resistant A. baumannii from bird and human hosts belonged to clonal complex 79, and harboured a small plasmid (⁓16.6-kb in size), named pAC1-BRL, which carried bla gene, macrolide resistance genes msrE and mphE, and the toxin-antitoxin system AbkAB. To determine the impact of pAC1-BRL acquisition in the the capacity of a microorganism to survive in a competitive environment (in the following called fitness), the laboratory strain A. baumannii ATCC 19606 was used in the fitness experiments and suggested an increase of its relative fitness after the pAC1-BRL acquisition. In summary, the detection of OXA-72-producing A. baumannii strains belonging to CC79 in aquatic birds is a piece of epidemiological evidence demonstrating that dissemination of high-risk bacteria is extending beyond the hospital.
鲍曼不动杆菌碳青霉烯耐药性是一个全球性的公共卫生问题，主要归因于碳青霉烯水解酶 D 类β-内酰胺酶（CHDLs）的产生。在巴西，临床分离株中 OXA-23 和 OXA-143 CHDLs 较为流行，环境样本中也有一些 OXA-23 的报道，而 OXA-72 则开始越来越多地被报道。本研究旨在对从巴西动物园一个湖泊中栖息的候鸟和圈养鸟中分离出的耐碳青霉烯鲍曼不动杆菌进行基因组和微生物学特征分析。从 2012 年 7 月至 8 月间，动物园湖中的 50 只候鸟和 37 只圈养鸟的鼻和泄殖腔拭子中，共分离出 481 株革兰氏阴性杆菌。在所有革兰氏阴性杆菌中，从 4 只候鸟和 5 只圈养水鸟的微生物群中检测到 9 株产 OXA-72 的鲍曼不动杆菌。产 OXA-72 的鲍曼不动杆菌分离株进行了药敏试验和 PFGE 分析，表现出多药耐药谱，并与在医院环境中流行了 18 年的 OXA-72 阳性人类分离株具有克隆相关性。MLST、质粒分析和全基因组测序显示，所有来自鸟类和人类宿主的耐碳青霉烯鲍曼不动杆菌均属于克隆复合体 79，携带一个小质粒（大小约为 16.6kb），命名为 pAC1-BRL，该质粒携带 bla 基因、大环内酯类耐药基因 msrE 和 mphE 以及毒素-抗毒素系统 AbkAB。为了确定 pAC1-BRL 的获得对微生物在竞争环境中生存能力的影响（以下称为适应性），在适应性实验中使用了实验室菌株鲍曼不动杆菌 ATCC 19606，结果表明，pAC1-BRL 的获得后，其相对适应性增加。综上所述，在水生鸟类中检测到属于 CC79 的产 OXA-72 的鲍曼不动杆菌菌株是传播高风险细菌超出医院范围的流行病学证据。
