Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
Appl Environ Microbiol. 2019 Jun 17;85(13). doi: 10.1128/AEM.00137-19. Print 2019 Jul 1.
and are human and animal gut commensals. Vancomycin-resistant enterococci (VRE) are important opportunistic pathogens with limited treatment options. Historically, the glycopeptide antibiotics vancomycin and avoparcin selected for the emergence of vancomycin resistance in human and animal isolates, respectively, resulting in global cessation of avoparcin use between 1997 and 2000. To better understand human- and animal-associated VRE strains in the postavoparcin era, we sequenced the genomes of 231 VRE isolates from New Zealand (NZ; 75 human clinical, 156 poultry) cultured between 1998 and 2009. lineages and their antibiotic resistance carriage patterns strictly delineated between agricultural and human reservoirs, with bacitracin resistance ubiquitous in poultry but absent in clinical strains. In contrast, one lineage (ST108) predominated in both poultry and human isolates in the 3 years following avoparcin discontinuation. Both phylogenetic and antimicrobial susceptibility (i.e., ubiquitous bacitracin resistance in both poultry and clinical ST108 isolates) analyses suggest an agricultural origin for the ST108 lineage. VRE isolate resistomes were carried on multiple, heterogeneous plasmids. In some isolate genomes, bacitracin, erythromycin, and vancomycin resistance elements were colocalized, indicating multiple potentially linked selection mechanisms. Historical antimicrobial use in NZ agriculture has driven the evolution of ST108, a VRE lineage carrying a range of clinically relevant antimicrobial resistances. The persistence of this lineage in NZ for over a decade indicates that coselection may be an important stabilizing mechanism for its persistence.
和 是人类和动物肠道共生菌。耐万古霉素肠球菌（VRE）是一种重要的机会性病原体，其治疗选择有限。历史上，糖肽类抗生素万古霉素和阿伏帕星分别选择了人类和动物分离株的万古霉素耐药性的出现，导致全球于 1997 年至 2000 年间停止使用阿伏帕星。为了更好地了解阿伏帕星使用后时代人类和动物相关的 VRE 菌株，我们对 1998 年至 2009 年间从新西兰（NZ）培养的 231 株 VRE 分离株的基因组进行了测序（75 株来自人类临床，156 株来自家禽）。和它们的抗生素耐药携带模式严格区分了农业和人类储集库，杆菌肽耐药在禽类中普遍存在，但在临床 株中不存在。相比之下，在阿伏帕星停用后的 3 年内，一个 株（ST108）在禽类和人类分离株中均占主导地位。系统发育和抗菌药物敏感性（即，禽类和临床 ST108 分离株均普遍存在杆菌肽耐药）分析表明，ST108 株系起源于农业。VRE 分离株的耐药组携带于多种异质质粒上。在一些分离株的基因组中，杆菌肽、红霉素和万古霉素耐药元件存在共定位，表明存在多种潜在的关联选择机制。新西兰农业的历史抗生素使用推动了 ST108 的进化，ST108 是一种携带多种临床相关抗生素耐药性的 VRE 株系。该株系在新西兰持续存在超过十年，表明共选择可能是其持续存在的一个重要稳定机制。
