McFarlane JA, Hansen EG, Ortega EC, Iskender I, Noireaux V, Bowden SD. A ToxIN homolog from Salmonella enterica serotype Enteritidis impairs bacteriophage infection.
J Appl Microbiol 2023;
134:lxad299. [PMID:
38059866 DOI:
10.1093/jambio/lxad299]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 11/19/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
AIMS
To determine if the bacteriophage abortive infection system ToxIN is present in foodborne Salmonella and if it protects against infection by bacteriophages specific to enteric bacteria.
METHODS AND RESULTS
A set of foodborne Salmonella enteritidis isolates from a 2010 eggshell outbreak was identified via BLASTN (basic local alignment search tool nucleotide) queries as harboring a close homolog of ToxIN, carried on a plasmid with putative mobilization proteins. This homolog was cloned into a plasmid vector and transformed into the laboratory strain Salmonella typhimurium LT2 and tested against a set of Salmonella-specific phages (FelixO1, S16, Sp6, LPST153, and P22 HT105/1 int-201). ToxIN reduced infection by FelixO1, S16, and LPST153 by ∼1-4 log PFU ml-1 while reducing the plaque size of Sp6. When present in LT2 and Escherichia coli MG1655, ToxIN conferred cross-genus protection against phage isolates, which infect both bacteria. Finally, the putative ToxIN plasmid was found in whole-genome sequence contigs of several Salmonella serovars, pathogenic E. coli, and other pathogenic enterobacteria.
CONCLUSIONS
Salmonella and E. coli can resist infection by several phages via ToxIN under laboratory conditions; ToxIN is present in foodborne pathogens including Salmonella and Shiga-toxigenic E. coli.
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