Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, Bejaia, Algeria.
Institut National de la Santé et de la Recherche Médicale, U1047, Université Montpellier, UFR de Médecine, Nîmes, France.
J Antimicrob Chemother. 2019 Jul 1;74(7):1848-1855. doi: 10.1093/jac/dkz146.
To investigate the prevalence and molecular characteristics of OXA-48-carbapenemase-producing Enterobacterales strains recovered from various ecological niches in Algeria.
In total, 3309 samples were collected from different ecological niches (human carriage, animal farms, wild animals, pets, food products, aquatic environment and wastewater treatment plants) distributed among six provinces in Algeria between December 2015 and April 2017. The potential presence of OXA-48-producing Enterobacterales isolates was screened on selective medium. Resistance and virulence profiles were characterized by PCR and sequencing. The clonal relatedness of the different isolates was studied using Rep-PCR and MLST. Conjugation was performed for all OXA-48-producing isolates. The plasmids were analysed by PCR-based replicon typing and WGS.
A total of 78 OXA-48-producing Enterobacterales isolates were detected from 3309 samples (2.4%). OXA producers were observed in all the screened sources. The blaCTX-M-15 gene was only observed in two isolates. Clonality analysis revealed distinct lineages of the isolates and a clonal expansion of Klebsiella pneumoniae ST13. K. pneumoniae and Escherichia coli had few virulence factors. Plasmid analysis confirmed that all the isolates harboured a very similar transferable plasmid (belonging to IncL) with a similar structure to the pOXA-48a plasmid carried by K. pneumoniae strain Kp11978.
This study suggests a global dissemination of OXA-48-producing Enterobacterales in different niches due mainly to the spread of an epidemic plasmid. Furthermore, it clearly shows that K. pneumoniae and commensal E. coli can be reservoirs of the blaOXA-48 gene, contributing to the dissemination and transfer of this gene to diverse bacteria among different sources.
调查在阿尔及利亚不同生态环境中分离的产 OXA-48 碳青霉烯酶肠杆菌科菌株的流行率和分子特征。
2015 年 12 月至 2017 年 4 月期间，我们从分布在阿尔及利亚六个省的不同生态环境（人体携带、动物养殖场、野生动物、宠物、食品、水生环境和污水处理厂）中收集了 3309 个样本。在选择性培养基上筛选产 OXA-48 的肠杆菌科分离株的潜在存在。通过 PCR 和测序分析其耐药性和毒力谱。使用 Rep-PCR 和 MLST 研究不同分离株的克隆相关性。对所有产 OXA-48 的分离株进行了接合实验。通过基于 PCR 的复制子分型和 WGS 分析质粒。
从 3309 个样本中检出 78 株产 OXA-48 的肠杆菌科分离株（2.4%）。在所有筛选的来源中均观察到 OXA 生产者。仅在两个分离株中观察到 blaCTX-M-15 基因。克隆性分析显示分离株存在不同的谱系，Klebsiella pneumoniae ST13 发生了克隆扩张。K. pneumoniae 和 Escherichia coli 具有较少的毒力因子。质粒分析证实所有分离株均携带一种非常相似的可转移质粒（属于 IncL），其结构与 K. pneumoniae 株 Kp11978 携带的 pOXA-48a 质粒相似。
本研究表明，产 OXA-48 的肠杆菌科在不同生态环境中的传播呈全球性，主要是由于流行质粒的传播。此外，它清楚地表明，K. pneumoniae 和共生 Escherichia coli 可以是 blaOXA-48 基因的储库，有助于该基因在不同来源的不同细菌之间的传播和转移。
