Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA
Division of Microbiology, U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA.
Microbiol Mol Biol Rev. 2021 Apr 28;85(2). doi: 10.1128/MMBR.00031-20. Print 2021 May 19.
Bacterial plasmids are extrachromosomal genetic elements that often carry antimicrobial resistance (AMR) genes and genes encoding increased virulence and can be transmissible among bacteria by conjugation. One key group of plasmids is the incompatibility group I1 (IncI1) plasmids, which have been isolated from multiple of food animal origin and clinically ill human patients. The IncI group of plasmids were initially characterized due to their sensitivity to the filamentous bacteriophage If1. Two prototypical IncI1 plasmids, R64 and pColIb-P9, have been extensively studied, and the plasmids consist of unique regions associated with plasmid replication, plasmid stability/maintenance, transfer machinery apparatus, single-stranded DNA transfer, and antimicrobial resistance. IncI1 plasmids are somewhat unique in that they encode two types of sex pili, a thick, rigid pilus necessary for mating and a thin, flexible pilus that helps stabilize bacteria for plasmid transfer in liquid environments. A key public health concern with IncI1 plasmids is their ability to carry antimicrobial resistance genes, including those associated with critically important antimicrobials used to treat severe cases of enteric infections, including the third-generation cephalosporins. Because of the potential importance of these plasmids, this review focuses on the distribution of the plasmids, their phenotypic characteristics associated with antimicrobial resistance and virulence, and their replication, maintenance, and transfer.
细菌质粒是染色体外的遗传元件，通常携带抗生素耐药性 (AMR) 基因和编码增加毒力的基因，并可通过接合在细菌之间传播。一类重要的质粒是不相容群 I1 (IncI1) 质粒，它们已从多种来源的食品动物和临床感染的人类患者中分离出来。IncI 组质粒最初因其对丝状噬菌体 If1 的敏感性而被特征化。两个典型的 IncI1 质粒，R64 和 pColIb-P9，已经得到了广泛的研究，这些质粒由与质粒复制、质粒稳定性/维持、转移机制装置、单链 DNA 转移和抗生素耐药性相关的独特区域组成。IncI1 质粒在某种程度上是独特的，因为它们编码两种类型的性菌毛，一种是用于交配的厚而刚性菌毛，另一种是薄而灵活的菌毛，有助于在液体环境中稳定细菌进行质粒转移。IncI1 质粒的一个关键公共卫生问题是它们能够携带抗生素耐药性基因，包括与用于治疗严重肠道感染的关键重要抗生素相关的基因，包括第三代头孢菌素。由于这些质粒的潜在重要性，本综述重点介绍了质粒的分布、与抗生素耐药性和毒力相关的表型特征，以及它们的复制、维持和转移。
