Yang Mingxing, Liu Dong, Li Xiaoquan, Xiao Chuting, Mao Yingge, He Jiaqi, Feng Jiao, Wang Li
Department of Clinical Laboratory, The First Affiliated Hospital of Henan University, Kaifeng, China.
Institute of Biomedical Sciences, The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education of China, The Key Laboratory of Medical Molecular Cell Biology of Shanxi Province, Shanxi University, Taiyuan, China.
Front Microbiol. 2023 May 18;14:1158659. doi: 10.3389/fmicb.2023.1158659. eCollection 2023.
Extended-spectrum beta-lactamase-producing Gram-negative bacteria are common in the community and hospitals. To monitor ESBLs mediated by the CTX-M genotype, we collected clinical ESBL pathogenic strains from a hospital in central China and observed a strain of , namely Ec15103 carrying , and , isolated from the blood of a 7-day-old infant in 2015. Strain Ec15103 contains two drug resistance plasmids: pEc15103A, an IncFI-type plasmid that cannot be conjugatively transferred and carries the drug resistance genes , , , , (A), , , and (A); and pEc15103B, an IncK2/Z-type plasmid that carries the conjugation transfer gene and . In addition, is located on the chromosome of Ec15103, and it is the first report of pathogen with located on its chromosome (the search terms used "blaCTX-M-64" and "chromosome"). and are carried by IS-mediated transposon Tn and Tn, respectively. The conjugation transfer ability of pEc15103B was significantly inhibited by zidovudine (AZT) and linoleic acid (LA) and that expression of , and at the mRNA level did not change based on the concentration of cefotaxime or ampicillin. Co-occurrence of and in a single isolate will enhance the drug resistance of bacteria, and the presence of in the chromosome may make the resistance more maintain. This fact will facilitate its dissemination and persistence under different antimicrobial selection pressures. It is essential to prevent these strains from further spreading in a hospital environment.
产超广谱β-内酰胺酶的革兰氏阴性菌在社区和医院中都很常见。为监测由CTX-M基因型介导的超广谱β-内酰胺酶，我们从中国中部一家医院收集了临床超广谱β-内酰胺酶致病菌株，并观察到一株名为Ec15103的菌株，它携带blaCTX-M-64、blaTEM-1和blaSHV-12，于2015年从一名7日龄婴儿的血液中分离得到。菌株Ec15103含有两个耐药质粒：pEc15103A，一种不能进行接合转移的IncFI型质粒，携带耐药基因blaCTX-M-64、blaTEM-1、blaSHV-12、aadA1、aph(3’)-Ia、qacEΔ1、sul1和tet(A)；以及pEc15103B，一种携带接合转移基因traJ和tnpA的IncK2/Z型质粒。此外，blaCTX-M-64位于Ec15103的染色体上，这是首次报道其染色体上携带blaCTX-M-64的病原体（搜索词使用“blaCTX-M-64”和“染色体”）。blaTEM-1和blaSHV-12分别由IS介导的转座子Tn2和Tn1携带。齐多夫定（AZT）和亚油酸（LA）显著抑制了pEc15103B的接合转移能力，并且blaCTX-M-64、blaTEM-1和blaSHV-12在mRNA水平的表达不会因头孢噻肟或氨苄西林的浓度而改变。单个分离株中blaCTX-M-64和blaTEM-1的共存会增强细菌的耐药性，而染色体上blaCTX-M-64的存在可能使耐药性更易维持。这一情况将有助于其在不同抗菌选择压力下的传播和持续存在。防止这些菌株在医院环境中进一步传播至关重要。
