biostudies-literatureQuereda JJEuropean Research CouncilAgence Nationale de la RechercheInstitut PasteurSwedish Research Council13https://www.ebi.ac.uk/biostudies/studies/S-EPMC5801685biostudies-literatureUnknown49(1)Most human listeriosis outbreaks are caused by Listeria monocytogenes evolutionary lineage I strains which possess four exotoxins: a phosphatidylinositol-specific phospholipase C (PlcA), a broad-range phospholipase C (PlcB), listeriolysin O (LLO) and listeriolysin S (LLS). The simultaneous contribution of these molecules to virulence has never been explored. Here, the importance of these four exotoxins of an epidemic lineage I L. monocytogenes strain (F2365) in virulence was assessed in chicken embryos infected in the allantoic cavity. We show that LLS does not play a role in virulence while LLO is required to infect and kill chicken embryos both in wild type transcriptional regulator of virulence PrfA (PrfA^WT) and constitutively active PrfA (PrfA*) backgrounds. We demonstrate tVeterinary researchRole in virulence of phospholipases, listeriolysin O and listeriolysin S from epidemic Listeria monocytogenes using the chicken embryo infection model.PMC5801685621-2012-2451260764 RNAntibioticsANR-15-CE15-0017 StopBugEntry260764670823670823 BacCellEpigrants K2011-56X-15144-08-6PTR521Cossart PQuereda JJAndersson CJohansson JPizarro-Cerda JfalseRole in virulence of phospholipases, listeriolysin O and listeriolysin S from epidemic Listeria monocytogenes using the chicken embryo infection model.Most human listeriosis outbreaks are caused by Listeria monocytogenes evolutionary lineage I strains which possess four exotoxins: a phosphatidylinositol-specific phospholipase C (PlcA), a broad-range phospholipase C (PlcB), listeriolysin O (LLO) and listeriolysin S (LLS). The simultaneous contribution of these molecules to virulence has never been explored. Here, the importance of these four exotoxins of an epidemic lineage I L. monocytogenes strain (F2365) in virulence was assessed in chicken embryos infected in the allantoic cavity. We show that LLS does not play a role in virulence while LLO is required to infect and kill chicken embryos both in wild type transcriptional regulator of virulence PrfA (PrfA^WT) and constitutively active PrfA (PrfA*) backgrounds. We demonstrate t2018-01-01T00:00:00Z2018 Feb2025-04-05T15:14:24.427Z2019-03-26T23:02:05ZS-EPMC58016852940952110.1186/s13567-017-0496-4