College of Veterinary Medicine, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.
mSphere. 2020 Jul 15;5(4):e00507-20. doi: 10.1128/mSphere.00507-20.
The plasmid-mediated fosfomycin resistance gene has been detected in from various sources but has rarely been reported in vegetables. In this study, the aim was to investigate the prevalence of and, subsequently, to characterize -positive isolates from retail vegetables. Seventeen (7.3%) -carrying strains were identified from 233 extended-spectrum-β-lactamase-producing isolates from vegetables. All 17 isolates, including six , seven , two , and two isolates, carried S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) and hybridization confirmed that the genes in 16 isolates were located on plasmids ranging in size from ∼40 kb to ∼250 kb, except one located on chromosome of All the carrying plasmids from 16 -positive isolates were successfully transferred into the recipient bacteria by transformation or conjugation. In agreement with data determined with isolates from food animals, the IncHI2/ST3 and IncN-F33:A-:B-/F33:A-:B plasmids were the main vectors of in Additionally, F24:A-:B1, IncFII-IncR, IncFII, IncR, and two untypeable plasmids were found for the first time to be vectors for in The genetic contexts of in 15 isolates differed due to insertion and/or loss of molecular modules mediated by mobile elements. However, all genes were flanked by IS, as commonly observed in other -carrying plasmids. Here, we report a high rate of detection of genes, mediated by multiple plasmid vectors, in ESBL-producing from retail vegetables. FosA3-producing could be transmitted to the human body by direct contact or consumption of vegetables, which might pose a potential threat to public health. This report provides important information on the transmission and epidemiology of among isolates from vegetables. The rate of occurrence of in ESBL-producing from retail vegetables is high, and was found to be carried by diverse plasmids. Some novel genetic contexts of and novel -carrying plasmids, including several plasmid types common in , were identified, increasing the number of known transfer vectors for the gene and reflecting the complexity of transmission in The capture of by the resident plasmid of will accelerate the spread of in , one of the most pathogenic species in clinical medicine. Considering the clinical importance of fosfomycin, and the fact that vegetables are directly consumed, the fosfomycin resistance genes present a risk of transmission to the human body through the food chain and thus pose a threat to public health.
从各种来源中都检测到了质粒介导的磷霉素耐药基因，但在蔬菜中很少有报道。本研究旨在调查零售蔬菜中磷霉素耐药基因的流行情况，并随后对阳性的 分离株进行特征分析。从 233 株产超广谱β-内酰胺酶的 分离株中，发现了 17 株（7.3%）携带 基因。17 株分离株中包括 6 株 、7 株 、2 株 、2 株 ，经 S1-核酸酶脉冲场凝胶电泳（S1-PFGE）和杂交证实，16 株 中的 基因位于大小为 40kb 到 250kb 的质粒上，只有一株位于 的染色体上。16 株阳性分离株的所有携带质粒均通过转化或接合成功转移到受体菌中。与从食品动物中分离到的菌株数据一致，IncHI2/ST3 和 IncN-F33:A-:B-/F33:A-:B 质粒是 在 中的主要载体。此外，首次发现 F24:A-:B1、IncFII-IncR、IncFII、IncR 和两种无法分型的质粒是 在 中的载体。15 株 中的 基因的遗传背景因移动元件介导的插入和/或缺失而不同。然而，所有 基因都被 IS 包围，这在其他携带 基因的质粒中很常见。本研究报告了在零售蔬菜中产超广谱β-内酰胺酶的 中，携带 基因的多种质粒载体的高检出率。产 FosA3 的 可通过直接接触或食用蔬菜传播到人体，这可能对公众健康构成潜在威胁。本报告提供了有关蔬菜中产超广谱β-内酰胺酶的 分离株中 传播和流行病学的重要信息。从零售蔬菜中分离出的产超广谱β-内酰胺酶的 中， 基因的发生率很高，并且发现 由多种质粒携带。鉴定了 基因的一些新的遗传背景和新型的 携带质粒，包括一些在 中常见的质粒类型，增加了已知的 基因转移载体的数量，反映了 在 中的传播的复杂性。 驻留质粒捕获 将加速 在 中的传播，而 是临床医学中最具致病性的物种之一。考虑到磷霉素的临床重要性，以及蔬菜直接食用的事实，磷霉素耐药基因通过食物链传播到人体的风险，对公众健康构成威胁。
