ZENG J, TENG F, WEINSTOCK GM, MURRAY BE; Interscience Conference on Antimicrobial Agents and Chemotherapy (43rd: 2003: Chicago, Ill.).
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2003 Sep 14-17; 43: abstract no. B-819.
University of Texas Medical School, Houston, TX.
BACKGROUND: Previously, our group identified an Enterococcus faecalis gene cluster, epa, which is involved in polysaccharide biosynthesis. The insertion disruption mutants TX5179 and TX5180 (which lack a major antigenic polysaccharide) were also shown to be important for virulence in mice and in resistance to PMN killing. In this study, the influence of epa genes on translocation of E. faecalis across monolayers of human colon carcinoma derived T84 cells and on infection by an E. faecalis specific phage (NPV-1) infection were studied. Methods and RESULTS: Wild type OG1RF, its epa mutants TX5179 and TX5180, and E.coli DH5a were used in this study. In translocation experiments, using a 12-well Transwell system with 3.0um pore size polycarbonate membrane and monolayers of polarized T84 cells (4-6 Transwells were used for each strain and the experiments were performed 3-4 times), E. coli DH5a and epa mutant TX5179 were not detected in the lower chamber at 6h, while translocation of TX5180 (with a more downstream epa disruption) across the T84 monolayer was decreased about 10-fold compared to OG1RF (which showed 10[3-4] CFU at 6h). The epa mutant with disrupted orfde4 gene, TX5179, was complemented with extrachromosomal orfde4 and its downstream co-transcribed gene orfde5, resulting in TX5179.1, which showed restored polysaccharide biosynthesis and mostly restored translocation. We also found that TX5179 could not be infected by the phage NPV-1, but with TX5179.1, phage infectivity was fully restored. CONCLUSIONS: In this work, we showed that E. faecalis OG1RF can translocate across a T84 monolayer and that the epa polysaccharide biosynthesis gene cluster, especially orfde4-5, is important for successful translocation. We also found that epa genes are necessary for NPV-1 infection of OG1RF. These finding extend previously reports of the important role of the epa gene cluster.
Publication Types:
Keywords:
- Animals
- Antigens
- Antigens, Bacterial
- Bacteriophages
- Enterococcus
- Enterococcus faecalis
- Enterocytes
- Genes, Regulator
- Humans
- Mice
- Multigene Family
- Polysaccharides
- Virulence
- genetics
- immunology
Other ID:
UI: 102266327
From Meeting Abstracts