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Resistance mechanisms adopted by a Salmonella Typhimurium mutant against bacteriophage

Wang, Changbao; Nie, Ting; Lin, Fuxing; Connerton, Ian F.; Lu, Zhaoxin; Zhou, Shoubiao; Hang, Hua

Authors

Changbao Wang

Ting Nie

Fuxing Lin

Ian F. Connerton

Zhaoxin Lu

Shoubiao Zhou

Hua Hang



Abstract

© 2019 Elsevier B.V. Bacteriophages have key roles in regulating bacterial populations in most habitats. A Salmonella Typhimurium mutant (N18) with impaired sensitivity to phage fmb-p1 was obtained and examined, the adsorption efficiency of fmb-p1 to N18 was reduced to 6%, compared to more than 97% for wild type S. Typhimurium CMCC50115. Reduced adsorption was accompanied by a reduction of 90% in the LPS content compared to wild type. Electron microscopy showed phage scattered around N18 with minimal engagement, while the phage were efficiently adsorbed to the wild type with tails oriented towards the bacterial surface. Evidence suggests fmb-p1 can slightly infect N18 and this does not give rise to an increase of phage titer. RT-qPCR data show that several Salmonella genes involved in lipopolysaccharide synthesis and five virulence related genes were down-regulated upon exposure of N18 to phage fmb-p1. In contrast, phage resistance related genes such as the SOS response, restriction-modification (RM), and Cas1 gene were up-regulated in N18. These data suggest that although inefficient adsorption and entry is the primary mechanism of resistance, transcriptional responses to phage exposure indicate that alternative resistance mechanisms against phage infection are also brought to bear, including digestion of phage nucleic acids and activation of the SOS. These findings may help develop strategies for biocontrol of Salmonella where multi-resistant bacteria are encountered or emerge in applications for food production, bioremediation or wastewater treatment.

Journal Article Type Article
Publication Date Nov 1, 2019
Journal Virus Research
Print ISSN 0168-1702
Electronic ISSN 1872-7492
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 273
Article Number 197759
Institution Citation Wang, C., Nie, T., Lin, F., Connerton, I. F., Lu, Z., Zhou, S., & Hang, H. (2019). Resistance mechanisms adopted by a Salmonella Typhimurium mutant against bacteriophage. Virus Research, 273, https://doi.org/10.1016/j.virusres.2019.197759
DOI https://doi.org/10.1016/j.virusres.2019.197759
Keywords bacteriophage; Salmonella; lipopolysaccharide; gene expression; virulence
Publisher URL https://www.sciencedirect.com/science/article/abs/pii/S0168170219304460

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