Assessment of the pathogenic potential of two Listeria monocytogenes human faecal carriage isolates.
Two human faeces carriage isolates of Listeria monocytogenes (H1 and H2) were compared to reference strains (ScottA and LO28) with regard to their lethality in 14-day-old chick embryos, their haemolytic and phospholipase (phosphatidylcholine-phospholipase C and phosphatidylinositol-phospholipase C) activities and their invasiveness towards Caco-2 cells. Experimental infection of chick embryos allowed discrimination of the strains into those exhibiting high virulence (ScottA and H2), those exhibiting slightly attenuated virulence (LO28) and those exhibiting low virulence (H1). A similar percentage mortality and time to death for embryos was observed when they were infected with H2 as was seen with infection by the reference strain ScottA. Therefore, human carriage strain H2 was considered potentially pathogenic. In contrast to H2 and ScottA, H1 exhibited low virulence. Using the tissue-culture cell-line model, it was found that carriage strain H1 was unable to enter Caco-2 cells efficiently, even though it was similar to the virulent strains in terms of the enzymic activities involved in pathogenicity. Detection of the internalins InlA and InlB, involved in the internalization of L. monocytogenes in the host cells, by immunoblot indicated that a truncated form of InlA was produced by H1. Taken together, these data provide a starting point for the study of the behaviour of two types of human faeces carriage strains and their characterization.
Olier
Maı Wenn
MW
Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
Pierre
Fabrice
F
Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
Lemaı Tre
Jean-Paul
JP
Laboratoire de Microbiologie, Faculté de Pharmacie, 7 boulevard Jeanne d'Arc, 21033 Dijon Cedex, France2.|Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
Divies
Charles
C
Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
Rousset
André
A
Laboratoire de Microbiologie, Faculté de Pharmacie, 7 boulevard Jeanne d'Arc, 21033 Dijon Cedex, France2.|Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
Guzzo
Jean
J
Laboratoire de Microbiologie, ENSBANA, 1 Esplanade Erasme, 21000 Dijon, France1.
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D018938:Caco-2 Cells; D002353:Carrier State / Q000382:microbiology*; D002642:Chick Embryo; D004847:Epithelial Cells / Q000382:microbiology; D005243:Feces / Q000382:microbiology*; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification / Q000201:enzymology / Q000472:pathogenicity* / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D014407:Tumor Cells, Cultured; D014774:Virulence
D001426:Bacterial Proteins; D008565:Membrane Proteins; C095768:inlB protein, Listeria monocytogenes; C069761:internalin protein, Bacteria