Department of Microbiology, School of Medicine, Yangzhou University, Yangzhou 225001, China.
Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
Molecules. 2022 Sep 2;27(17):5665. doi: 10.3390/molecules27175665.
The CRISPR-Cas system is a bacterial and archaea adaptive immune system and is a newly recognized mechanism for controlling antibiotic resistance gene transfer. () is an important organism responsible for a variety of nosocomial infections. infections have become problematic worldwide because of the resistance of to multiple antibiotics. Thus, it is clinically significant to explore the relationship between the CRISPR-Cas system and drug resistance in . This study aimed to analyze the genomic characteristics of the strain AB3 containing the type I-Fb CRISPR-Cas system, which was isolated from a tertiary care hospital in China, and to investigate the relationship between the CRISPR-Cas system and antibiotic resistance in this strain. The whole-genome sequencing (WGS) of the AB43 strain was performed using Illumina and PacBio sequencing. The complete genome of AB43 consisted of a 3,854,806 bp chromosome and a 104,309 bp plasmid. The specific characteristics of the CRISPR-Cas system in AB43 are described as follows: (1) The strain AB43 carries a complete type I-Fb CRISPR-Cas system; (2) Homology analysis confirmed that the genes in AB43 share high sequence similarity with the same subtype genes; (3) A total of 28 of 105 AB43 CRISPR spacers matched genes in the bacteriophage genome database and the plasmid database, implying that the CRISPR-Cas system in AB43 provides immunity against invasive bacteriophage and plasmids; (4) None of the CRISPR spacers in AB43 were matched with antimicrobial resistance genes in the NCBI database. In addition, we analyzed the presence of antibiotic resistance genes and insertion sequences in the AB43 strain and found that the number of antibiotic resistance genes was not lower than in the "no CRISPR-Cas system" strain. This study supports the idea that the CRISPR-Cas system may inhibit drug-resistance gene expression via endogenous gene regulation, except to the published mechanism that the CRISPR-Cas system efficiently limits the acquisition of antibiotic resistance genes that make bacteria sensitive to antibiotics.
CRISPR-Cas 系统是细菌和古菌的适应性免疫系统，是一种新发现的控制抗生素耐药基因转移的机制。（）是一种重要的生物体，负责多种医院感染。由于（）对多种抗生素的耐药性，感染已成为全球性问题。因此，探索（）中 CRISPR-Cas 系统与耐药性之间的关系具有重要的临床意义。本研究旨在分析从中国一家三级医院分离的携带 I-Fb 型 CRISPR-Cas 系统的 AB3 菌株的基因组特征，并探讨该菌株 CRISPR-Cas 系统与抗生素耐药性的关系。采用 Illumina 和 PacBio 测序对 AB43 菌株进行全基因组测序（WGS）。AB43 的完整基因组由 3854806bp 染色体和 104309bp 质粒组成。AB43 中 CRISPR-Cas 系统的具体特征如下：（1）该菌株携带完整的 I-Fb 型 CRISPR-Cas 系统；（2）同源性分析证实 AB43 中的（）基因与同亚型的（）基因具有高度的序列相似性；（3）AB43 的 105 个 CRISPR 间隔区中的 28 个与噬菌体基因组数据库和质粒数据库中的基因匹配，表明 AB43 中的 CRISPR-Cas 系统提供了针对侵袭性噬菌体和质粒的免疫；（4）AB43 中的 CRISPR 间隔区与 NCBI 数据库中的抗生素耐药基因均不匹配。此外，我们分析了 AB43 菌株中抗生素耐药基因和插入序列的存在情况，发现抗生素耐药基因的数量并不低于“无 CRISPR-Cas 系统”菌株。本研究支持 CRISPR-Cas 系统可能通过内源基因调控抑制耐药基因表达的观点，除了已发表的 CRISPR-Cas 系统能有效限制使细菌对抗生素敏感的抗生素耐药基因的获得的机制之外。
