title: Fate of Viable but Non-culturable Listeria monocytogenes in Pig Manure Microcosms.
abstract: The fate of two strains of Listeria monocytogenes and their ability to become viable but non-culturable (VBNC) was investigated in microcosms containing piggery eﬄuents (two raw manures and two biologically treated manures) stored for 2 months at 8 and 20°C. Levels of L. monocytogenes were estimated using the culture method, qPCR, and propidium monoazide treatment combined with qPCR (qPCRPMA). The chemical composition and the microbial community structure of the manures were also analyzed. The strains showed similar decline rates and persisted up to 63 days. At day zero, the percentage of VBNC cells among viable cells was higher in raw manures (81.5-94.8%) than in treated manures (67.8-79.2%). The changes in their proportion over time depended on the temperature and on the type of eﬄuent: the biggest increase was observed in treated manures at 20°C and the smallest increase in raw manures at 8°C. The chemical parameters had no influence on the behavior of the strains, but decrease of the persistence of viable cells was associated with an increase in the microbial richness of the manures. This study demonstrated that storing manure altered the culturability of L. monocytogenes, which rapidly entered the VBNC state, and underlines the importance of including VBNC cells when estimating the persistence of the pathogens in farm eﬄuents.
authors.affiliation: Irstea-RennesRennes, France; Université Européenne de BretagneRennes, France.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Desneux
authors.affiliation: Irstea-RennesRennes, France; Université Européenne de BretagneRennes, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Biscuit
authors.affiliation: Irstea-RennesRennes, France; Université Européenne de BretagneRennes, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Picard
authors.affiliation: Irstea-RennesRennes, France; Université Européenne de BretagneRennes, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Pourcher
keywords: L. monocytogenes; PMA; VBNC state; manure; microcosm; pyrosequencing