title: Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars.
abstract: Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs.
authors.affiliation: Microbial Ecology Group, National Research Council - Institute of Ecosystem Study (CNR-ISE), Largo Tonolli 50,28822, Verbania, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Cesare
authors.affiliation: Food Safety Department, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell'Università 10, 35020, Legnaro, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Losasso
authors.affiliation: Food Safety Department, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell'Università 10, 35020, Legnaro, Italy.
authors.forename: Lisa
authors.initials: L
authors.lastname: Barco
authors.affiliation: Microbial Ecology Group, National Research Council - Institute of Ecosystem Study (CNR-ISE), Largo Tonolli 50,28822, Verbania, Italy.
authors.forename: Ester M
authors.initials: EM
authors.lastname: Eckert
authors.affiliation: Department Animal Medicine, Production and Health, University of Padua, viale dell'Università, 35020, Legnaro, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Conficoni
authors.affiliation: Microbial Ecology Group, National Research Council - Institute of Ecosystem Study (CNR-ISE), Largo Tonolli 50,28822, Verbania, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Sarasini
authors.affiliation: Microbial Ecology Group, National Research Council - Institute of Ecosystem Study (CNR-ISE), Largo Tonolli 50,28822, Verbania, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Corno
authors.affiliation: Food Safety Department, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell'Università 10, 35020, Legnaro, Italy.
authors.forename: Antonia
authors.initials: A
authors.lastname: Ricci
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D010957:Plasmids; D016133:Polymerase Chain Reaction; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D065288:Serogroup; D000075704:Toxin-Antitoxin Systems / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C068355:CcdA protein, Bacteria; D004268:DNA-Binding Proteins; D008562:Membrane Glycoproteins; C077517:VapB protein, Bacteria