Detection of conjugal transfer systems in oral, black-pigmented Bacteroides spp.

Abstract

Oral, black-pigmented Bacteroides spp. are important pathogens in oral anaerogic infections and dental disease. We detected conjugation systems in isolates of Bacteroides denticola and Bacteroides intermedius that transferred tetracycline resistance (Tet(r)) and penicillin resistance to Bacteroides buccae and to Bacteroides fragilis, an intestinal Bacteroides species. A cloned Tet(r) gene from B. fragilis hybridized to the transferable Tet(r) locus in the oral strains, indicating that genetic exchange occurs between these two groups of anaerobes.