Induction of resistance to S. aureus in an environmental marine biofilm grown in Sydney Harbor, NSW, Australia.

The study of environmental biofilms is complicated by the difficulty of working with them under lab conditions. Nonetheless, knowledge of cellular activity and interactions within environmental biofilms could lead to novel biomedical applications. To address this problem we previously proposed a new technique for inducing resistance to Staphylococcus aureus in an intact environmental biofilm. In the current follow-up study we applied the new technique in a biogeographically distinct environment using a different strain of S. aureus. The proposed technique for inducing resistance to S. aureus in an environmental biofilm involves growing the environmental biofilms over several days in media reflecting their natural habitat on agar that contains spent culture supernatant from S. aureus over-night culture. We found in this second study that it was possible to induce resistance to S. aureus in an environmental biofilm from a biogeographically distinct environment, though not in the same way as we had previously observed. Environmental consortia from Sydney Harbor, Australia display an ability to inhibit biofilm formation by S. aureus; only in the case where the environmental biofilms were pretreated with UV radiation was there a difference in activity between environmental consortia grown on plain agar, and that grown on S. aureus agar. Application of the new technique in the current study also differs in that significant killing of cells within an established S. aureus biofilm by environmental consortia grown on S. aureus agar was possible.