Fate of Bacillus cereus within phagocytic cells

ROLNY I.S.; RACEDO, S.M.; PEREZ P.F.

INTERNATIONAL MICROBIOLOGY

VIGUERA EDITORES

Lugar: Barcelona; Año: 2017 vol. 20

1139-6709

In this study we assessed the interaction of different strains of Bacillus cereus with murine peritoneal macrophagesand cultured phagocytic cells (Raw 264.7 cells). Association, internalization, intracellular survival, routing of bacteria to differentcompartments and expression of MHCII were assessed in cells infected with different strains of B. cereus in vegetative form.Association values (adhering + internalized bacteria) and phagocytosis were higher for strain B10502 than those for strains 2 andM2. However, after 90 min interaction, intracellular survival was higher for strain 2 than for strains M2 and B10502. Acquisitionof lysosomal markers by B. cereus containing vacuoles (BcCV), assessed by LAMP1 and Lysotracker labelling occurred shortlyafter internalization. The highest ratio of LAMP1(+)-BcCV was found for strain M2. This strain was able to survive longer thanstrain B10502 which routes to LAMP1 containing vacuoles to a lesser extent. In addition, strain M2 stimulated expression ofMHCII by infected cells. Confocal analyses 60 or 90 min post-infection showed different percentages of co-localization of bacteriawith Lysotracker. Results suggest strain-dependent interaction and intracellular killing of B. cereus by phagocytic cells. Thesefindings could be relevant for the pathogenic potential of Bacillus cereus strains.