BACKGROUND: Internalin mediates entry of Listeria monocytogenes into some human cultured cell lines and crossing of the intestinal barrier in transgenic mice expressing its receptor, human E-cadherin, in enterocytes. The relevance of these findings for humans is challenged by the observation that some L. monocytogenes isolates express a truncated nonfunctional form of internalin. METHODS: We investigated expression of internalin by use of immunoblot assay in 300 clinical strains obtained in France in a single year and a representative set of 150 strains obtained from food products during the same period. RESULTS: Clinical strains expressed full-length internalin far more frequently (288/300 strains [96%]) than did strains recovered from food products (98/150 strains [65%]; odds ratio, 12.73; 95% confidence interval, 6.27-26.34; P<1 x 10(-7)). All 61 strains (100%) from pregnancy-related cases, 55 (98%) of 56 strains from patients with central nervous system infections, and 151 (93%) of 162 strains from patients with bacteremia expressed full-length internalin. All 110 strains belonging to serovar 4b, the most frequently implicated serovar in human listeriosis, expressed full-length internalin. CONCLUSIONS: This study demonstrates the critical role of internalin in the pathogenesis of human listeriosis. It provides a molecular explanation for the predominance of serovar 4b among clinical strains and supports the usefulness of studying the expression of internalin as a marker of virulence in humans.
BACKGROUND: Internalin mediates entry of Listeria monocytogenes into some human cultured cell lines and crossing of the intestinal barrier in transgenic mice expressing its receptor, humanE-cadherin, in enterocytes. The relevance of these findings for humans is challenged by the observation that some L. monocytogenes isolates express a truncated nonfunctional form of internalin. METHODS: We investigated expression of internalin by use of immunoblot assay in 300 clinical strains obtained in France in a single year and a representative set of 150 strains obtained from food products during the same period. RESULTS: Clinical strains expressed full-length internalin far more frequently (288/300 strains [96%]) than did strains recovered from food products (98/150 strains [65%]; odds ratio, 12.73; 95% confidence interval, 6.27-26.34; P<1 x 10(-7)). All 61 strains (100%) from pregnancy-related cases, 55 (98%) of 56 strains from patients with central nervous system infections, and 151 (93%) of 162 strains from patients with bacteremia expressed full-length internalin. All 110 strains belonging to serovar 4b, the most frequently implicated serovar in human listeriosis, expressed full-length internalin. CONCLUSIONS: This study demonstrates the critical role of internalin in the pathogenesis of human listeriosis. It provides a molecular explanation for the predominance of serovar 4b among clinical strains and supports the usefulness of studying the expression of internalin as a marker of virulence in humans.
Authors: Hadewig Werbrouck; Koen Grijspeerdt; Nadine Botteldoorn; Els Van Pamel; Nancy Rijpens; Jo Van Damme; Mieke Uyttendaele; Lieve Herman; Els Van Coillie Journal: Appl Environ Microbiol Date: 2006-06 Impact factor: 4.792
Authors: S M Roche; P Gracieux; E Milohanic; I Albert; I Virlogeux-Payant; S Témoin; O Grépinet; A Kerouanton; C Jacquet; P Cossart; P Velge Journal: Appl Environ Microbiol Date: 2005-10 Impact factor: 4.792
Authors: Marc Lecuit; D Michael Nelson; Steve D Smith; Huot Khun; Michel Huerre; Marie-Cécile Vacher-Lavenu; Jeffrey I Gordon; Pascale Cossart Journal: Proc Natl Acad Sci U S A Date: 2004-04-08 Impact factor: 11.205
Authors: Matthew W Gilmour; Morag Graham; Gary Van Domselaar; Shaun Tyler; Heather Kent; Keri M Trout-Yakel; Oscar Larios; Vanessa Allen; Barbara Lee; Celine Nadon Journal: BMC Genomics Date: 2010-02-18 Impact factor: 3.969