A novel means of self-protection, unrelated to toxin activation, confers immunity to the bactericidal effects of the Enterococcus faecalis cytolysin

Citation
Ps. Coburn et al., A novel means of self-protection, unrelated to toxin activation, confers immunity to the bactericidal effects of the Enterococcus faecalis cytolysin, INFEC IMMUN, 67(7), 1999, pp. 3339-3347
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Immunology
Journal title
INFECTION AND IMMUNITY
ISSN journal
0019-9567 → ACNP
Volume
67
Issue
7
Year of publication
1999
Pages
3339 - 3347
Database
ISI
SICI code
0019-9567(199907)67:7<3339:ANMOSU>2.0.ZU;2-K
Abstract
Enterococcus faecalis has become a pervasive clinical problem due to the em ergence of resistance to most antibiotics. The cytolysin of E. faecalis is a novel bacterial toxin that contributes to the severity of disease. It con sists of two structural subunits, which together possess both hemolytic and bactericidal activity. Both toxin subunits are encoded in a complex operon frequently harbored on pheromone-responsive plasmids. E. faecalis strains lacking such plasmids are susceptible to the bactericidal effects of the cy tolysin. A novel cytolysin immunity determinant at the 3' end of the pAD1 c ytolysin operon is described in the present study. Deletion analysis and sp ecific mutagenesis isolated the immunity function to a single open reading frame. Specific mutagenesis experiments demonstrate that cytolysin immunity is unrelated to cytolysin activator (CylA) expression as previously propos ed. Cytolysin immunity is, however, encoded on the same transcript as and 3 ' to CylA, and previous associations between immunity and CylA can be ascri bed to the polar behavior of Tn917 insertion.