Li Ying, Liu Qian, Qiu Yichuan, Fang Chengju, Zhou Yungang, She Junping, Chen Huan, Dai Xiaoyi, Zhang Luhua
The School of Basic Medical Science and Public Center of Experimental Technology, Southwest Medical University, Luzhou, Sichuan, China.
Immune Mechanism and Therapy of Major Diseases of Luzhou Key Laboratory, School of Basic Medical Science, Southwest Medical University, Luzhou, Sichuan, China.
Front Microbiol. 2022 Aug 24;13:977356. doi: 10.3389/fmicb.2022.977356. eCollection 2022.
Multidrug-resistant (MDR) , especially those strains producing extended-spectrum β-lactamases (ESBL) and carbapenemases, represents a major public health concern. In the present work, we characterized 27 MDR clinical isolates, including 23 , three , and one , by whole-genome analysis. Among the 27 isolates analyzed, SXT/R391 ICEs were detected in 14 strains, and the complete sequences of nine ICEs were obtained. These ICEs share a common backbone structure but also have different gene contents in hotspots and variable regions. Among them, ICEChn2826, ICEChn2833, ICEChn3105, and ICEChn3725 contain abundant antibiotic resistance genes, including the ESBL gene . The core gene phylogenetic analysis of ICEs showed their genetic diversity, and revealed the cryptic dissemination of them in strains from food animals and humans on a China-wide scale. One of the isolates, FZP3105, acquired an NDM-1-producing MDR plasmid, designated pNDM_FZP3105, which is a self-transmissible type 1/2 hybrid IncC plasmid. Analysis of the genetic organization showed that pNDM_FZP3105 has two novel antibiotic resistance islands bearing abundant antibiotic resistance genes, among which is located in a 9.0 kb ΔTn bracketed by two copies of IS in the same direction. In isolates FZP2936 and FZP3115, was detected on an IncN plasmid, which is identical to the previously reported pT211 in Zhejiang province of China. Besides, a MDR genomic island PmGRI1, a variant of PmGRI1-YN9 from chicken in China, was identified on their chromosome. In conclusion, this study demonstrates abundant genetic diversity of mobile genetic elements carrying antibiotic resistance genes, especially ESBL and carbapenemase genes, in clinical isolates, and highlights that the continuous monitoring on their transmission and further evolution is needed.
多重耐药（MDR）菌，尤其是那些产生超广谱β-内酰胺酶（ESBL）和碳青霉烯酶的菌株，是一个重大的公共卫生问题。在本研究中，我们通过全基因组分析对27株MDR临床分离株进行了特征分析，其中包括23株[具体菌株类型未提及]、3株[具体菌株类型未提及]和1株[具体菌株类型未提及]。在分析的27株分离株中，14株检测到SXT/R391整合性接合元件（ICE），并获得了9个ICE的完整序列。这些ICE具有共同的主干结构，但在热点区域和可变区域也有不同的基因内容。其中，ICEChn2826、ICEChn2833、ICEChn3105和ICEChn3725含有丰富的抗生素抗性基因，包括ESBL基因[具体基因名称未提及]。ICE的核心基因系统发育分析显示了它们的遗传多样性，并揭示了它们在中国范围内来自食用动物和人类的菌株中的隐秘传播。其中一株分离株FZP3105获得了一个产生NDM-1的MDR质粒，命名为pNDM_FZP3105，它是一种自我传递的1/2型杂交IncC质粒。遗传组织分析表明，pNDM_FZP3105有两个携带丰富抗生素抗性基因的新型抗生素抗性岛，其中[具体基因名称未提及]位于一个由两个同向IS拷贝包围的9.0 kb ΔTn中。在分离株FZP2936和FZP3115中，[具体基因名称未提及]在一个IncN质粒上被检测到，该质粒与中国浙江省先前报道的pT211相同。此外，在它们的染色体上鉴定出一个MDR基因组岛PmGRI1，它是中国鸡源PmGRI1-YN9的变体。总之，本研究证明了临床分离株中携带抗生素抗性基因，尤其是ESBL和碳青霉烯酶基因的移动遗传元件具有丰富的遗传多样性，并强调需要对它们的传播和进一步进化进行持续监测。
