Impact of Plasmid-Encoded H-NS-like Protein on blaNDM-1-Bearing IncX3 Plasmid in Escherichia coli

• Published in: The Journal of infectious diseases Vol. 221; no. Suppl 2; pp. S229 - S236
• Main Authors: Liu, Baomo, Shui, Lili, Zhou, Kai, Jiang, Ying, Li, Xiaoyu, Guan, Jing, Li, Qi, Zhuo, Chao
• Format: Journal Article
• Language: English
• Published: United States 16.03.2020
• Subjects: Anti-Bacterial Agents - therapeutic use; Bacterial Proteins - genetics; beta-Lactamases - genetics; Carbapenem-Resistant Enterobacteriaceae - genetics; China; Drug Resistance, Multiple, Bacterial - genetics; Enterobacteriaceae Infections - microbiology; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Gene Transfer, Horizontal - genetics; Humans; Microbial Sensitivity Tests; Multilocus Sequence Typing; Plasmids - genetics; Virulence - genetics; China; IncX3 plasmid; H-NS-like protein; bla NDM-1; dissemination; E. coli
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jiz567

This study was performed to assess the role of the histone-like nucleoid-structuring (H-NS)-like protein, carried by blaNDM-1-encoding IncX3-type plasmids, in the dissemination of IncX3 plasmids. The blaNDM-1-encoding IncX3 plasmids were analyzed using southern blot, conjugation, and competition assays. Virulence was evaluated with a Galleria mellonella infection model. An hns-knockout IncX3 plasmid was also constructed to identify the functions of plasmid-borne H-NS-like protein in Escherichia coli. The assasys detected blaNDM-1-encoding IncX3-type plasmids with similar fingerprint patterns in all New Delhi metallo-β-lactamase (NDM) 1-producing carbapenem-resistant Enterobacteriaceae. The IncX3 plasmid conferred a fitness advantage to E. coli J53 but had no effect on host virulence. Moreover, the transconjugation frequency of the hns-null IncX3 plasmid pHN330-△hns was increased by 2.5-fold compared with the wild type. This was caused by up-regulation of conjugation-related plasmid-borne genes and the partition-related gene, in the J330-pHN330-△hns strain. In addition, decreased virulence was detected with this variant. Our results highlight the important role of IncX3 plasmids in the dissemination of blaNDM-1 in south China. Plasmid-encoded H-NS-like protein can inhibit plasmid conjugation, partition, and the expression of related genes, in addition to promoting virulence in the host.