title: Differential internalin A levels in biofilms of Listeria monocytogenes grown on different surfaces and nutrient conditions.
abstract: Listeria monoctyogenes is a foodborne pathogen containing the surface protein, internalin A (InlA). The expression of this protein permits the invasion of L. monocytogenes into intestinal epithelial cells expressing the receptor E-cadherin, thus crossing the intestinal barrier and resulting in listerosis. The main aim of this work was to investigate InlA levels in different L. monocytogenes strains in both planktonic and sessile states using an anti-InlA antibody. Biofilms were grown in high and low nutrient environments on glass, stainless steel and polytetrafluoroethylene (PTFE). This study demonstrated that InlA levels varied greatly between strains and serotypes of L. monocytogenes. However, the serotypes 1/2a, 1/2b and 4b, associated with the largest number of outbreaks of listerosis consistently showed the highest InlA levels, regardless of nutrient content or planktonic or sessile state. Differences in InlA levels were also observed in biofilms grown on different surfaces such as glass, stainless steel and PTFE, with a significant reduction in InlA levels observed in biofilms on PTFE. Interestingly, although a large number of the total cells observed in biofilms formed in tap-water were non-cultivable, the virulence factor, InlA, was expressed at levels between 78 and 85%, thus indicating that these cells may still be virulent. A greater understanding of the factors that affect the levels of InlA on the surface of L. monocytogenes, is essential in the appreciation of the role of InlA in the persistence of biofilms containing L. monocytogenes and their potential to cause food borne disease.
authors.affiliation: School of Biotechnology, Dublin City University, Dublin, 9, Ireland; Biomedical Diagnostics Institute, Dublin City University, Dublin, 9, Ireland. Electronic address: niamh.gilmartin@gmail.com.
authors.forename: Niamh
authors.initials: N
authors.lastname: Gilmartin
authors.affiliation: Centre for Biological Sciences, University of Southampton, Life Sciences Building, Highfield Campus, Southampton SO17 1BJ, UK.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Gião
authors.affiliation: Centre for Biological Sciences, University of Southampton, Life Sciences Building, Highfield Campus, Southampton SO17 1BJ, UK.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Keevil
authors.affiliation: School of Biotechnology, Dublin City University, Dublin, 9, Ireland; Biomedical Diagnostics Institute, Dublin City University, Dublin, 9, Ireland.
authors.forename: Richard
authors.initials: R
authors.lastname: O'Kennedy
mesh_terms: D000906:Antibodies / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D004777:Environment; D005516:Food Microbiology; D005517:Foodborne Diseases; D005898:Glass; D008089:Listeria monocytogenes / Q000145:classification / Q000378:metabolism* / Q000472:pathogenicity; D008565:Membrane Proteins; D011138:Polytetrafluoroethylene; D013193:Stainless Steel; D013499:Surface Properties; D037521:Virulence Factors / Q000096:biosynthesis*; D014867:Water
chemical_list: D000906:Antibodies; D001426:Bacterial Proteins; D008565:Membrane Proteins; D037521:Virulence Factors; D014867:Water; D013193:Stainless Steel; C069761:internalin protein, Bacteria; D011138:Polytetrafluoroethylene
keywords: Biofilms; Internalin A; Listeria monocytogenes; Planktonic cells