Shenzhen Institute of Respiratory Diseases, the First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, and Second Clinical Medical College, Jinan University, Shenzhen, China; State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou, China.
State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou, China.
Int J Antimicrob Agents. 2020 Sep;56(3):106079. doi: 10.1016/j.ijantimicag.2020.106079. Epub 2020 Jul 4.
An increasing trend of the coexistence of a rare extended-spectrum β-lactamase gene bla and carbapenemase genes in Enterobacteriaceae has recently been noted. This study aimed to determine the epidemiological and genetic characterisation of SFO-1-positive carbapenem-resistant Enterobacter cloacae complex (CREC) isolates. A total of 61 CREC clinical isolates were collected in the framework of a national surveillance for carbapenem-resistant Enterobacteriaceae during 2011-2015 in China. Seven SFO-1-positive CREC isolates (11.5%) were identified in four provinces, suggesting a wide dissemination of the bla gene among the CREC population in China. Five SFO-1-positive CREC isolates were further identified by screening 1625 genomes of E. cloacae complex strains retrieved from GenBank. The 12 SFO-1-positive CREC isolates were further identified as Enterobacter hormaechei, of which 10 belonged to epidemic clones (ST93, ST114 and ST418), indicating that these clones might largely contribute to the dissemination of bla. Phylogenomics analysis further identified the occurrence of clonal dissemination in the community setting. The bla-bearing plasmids were assigned to various incompatibility groups with highly diverse sizes (~104-370 kb), suggesting a wide vector range of bla. Two types of genetic context, with and without insertion sequence IS26, were identified for the bla gene. The genetic context flanked by IS26 was more prevalent, thus largely facilitating the mobility of bla. This study revealed that the bla gene is not as rare as previously found and that epidemic clones of CREC are responsible for its dissemination in China. These findings highlight the potential of wide dissemination of low-prevalence antimicrobial resistance genes.
近年来，肠杆菌科中同时存在罕见的扩展谱β-内酰胺酶基因 bla 和碳青霉烯酶基因的趋势不断增加。本研究旨在确定 SFO-1 阳性碳青霉烯耐药肠杆菌科复合菌（CREC）分离株的流行病学和遗传特征。在中国，2011-2015 年期间，在全国范围内对碳青霉烯耐药肠杆菌科进行监测，共收集了 61 株 CREC 临床分离株。在四个省份发现了 7 株 SFO-1 阳性 CREC 分离株（11.5%），表明 bla 基因在中国 CREC 人群中广泛传播。通过筛选从 GenBank 中检索到的 1625 株肠杆菌科复合菌菌株，进一步鉴定了 5 株 SFO-1 阳性 CREC 分离株。12 株 SFO-1 阳性 CREC 分离株进一步鉴定为蜂房哈夫尼菌，其中 10 株属于流行克隆（ST93、ST114 和 ST418），表明这些克隆可能在很大程度上促进了 bla 的传播。系统发育基因组分析进一步证实了社区环境中克隆传播的发生。携带 bla 的质粒被分配到各种不相容群，大小差异很大（~104-370kb），表明 bla 的载体范围很广。鉴定出 bla 基因存在两种遗传结构，一种带有插入序列 IS26，另一种没有。带有 IS26 的 bla 基因遗传结构更为普遍，因此在很大程度上促进了 bla 的移动性。本研究表明，bla 基因并不像之前发现的那样罕见，CREC 的流行克隆负责其在中国的传播。这些发现强调了低流行率的抗菌药物耐药基因广泛传播的潜力。
