Transfer of Tn916-Like Elements in Microcosm Dental Plaques

Microcosm dental plaques were grown from an inoculum of human saliva in a constant-depth film fermentor. The inoculum contained four tetracycline-resistant streptococcal species, each of which contained a Tn916-like element. This element was shown to transfer to other streptococci both in filter-mating experiments and within the biofilms in the fermentor.