College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, China.
College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou, 450002, China.
Sci Rep. 2020 Feb 11;10(1):2360. doi: 10.1038/s41598-020-59341-4.
To date, bla and bla genes have been found predominantly in clinical settings around the world. In contrast, bacteria harbouring these two genes from natural environments are relatively less well studied compared to those found in clinical settings. In this study, a carbapenem-resistant Raoultella ornithinolytica strain, WLK218, was isolated from urban river sediment in Zhengzhou City, Henan Province, China. This isolate was subjected to PCR and antimicrobial susceptibility testing. PCR results showed that this isolate was positive for both the bla and bla genes. The antimicrobial susceptibility testing results showed that this isolate exhibited resistance or intermediate resistance to all the antibiotics tested except for streptomycin (susceptible) and cefepime (susceptible-dose dependent). The complete genome sequence of the WLK218 isolate was then determined by using a combination of the PacBio and Illumina sequencing technologies. The de novo assembly of the genome generated one chromosome and six plasmids. Among the six plasmids, the bla gene was carried on the IncX3 plasmid pWLK-NDM, while the bla gene was located on the untypeable plasmid pWLK-KPC. This is the first report of an environmental Raoultella ornithinolytica isolate co-harbouring the bla and bla genes.
迄今为止，bla 和 bla 基因主要在世界各地的临床环境中发现。相比之下，与在临床环境中发现的这些基因相比，来自自然环境的携带这些两个基因的细菌的研究相对较少。在这项研究中，从中国河南省郑州市城市河流沉积物中分离到一株耐碳青霉烯的鸟氨酸罗伊氏菌（Raoultella ornithinolytica）菌株 WLK218。该分离株进行了 PCR 和抗菌药物敏感性测试。PCR 结果显示，该分离株同时携带 bla 和 bla 基因。抗菌药物敏感性测试结果表明，该分离株除对链霉素（敏感）和头孢吡肟（敏感剂量依赖性）外，对所有测试的抗生素均表现出耐药或中介耐药。然后，使用 PacBio 和 Illumina 测序技术的组合，确定了 WLK218 分离株的完整基因组序列。通过对基因组进行从头组装，生成了一个染色体和六个质粒。在这六个质粒中，bla 基因位于 IncX3 质粒 pWLK-NDM 上，而 bla 基因位于无法分型的质粒 pWLK-KPC 上。这是首例环境鸟氨酸罗伊氏菌（Raoultella ornithinolytica）分离株同时携带 bla 和 bla 基因的报道。
