Adherence to and accumulation of S. epidermidis on different biomaterials due to extracellular slime production. In vitro comparison of a slime-producing strain (Rp 62 A) and its isogenic slime negative mutant (M7).

In an in vitro study, the bacterial adherence of a slime-producing strain (RP 62 A) was compared with its isogenic slime-negative mutant (M7). Standardized biomaterial discs were incubated under growth conditions in tryptic soy broth containing either strain RP 62 A or M7. After 24 h of incubation, the attached bacteria were removed by sonication and the colony-forming units were counted after plating of serial dilutions. We observed a significantly increased adherence and accumulation of the slime-producing strain (RP 62 A). In contrast to the slime negative mutant (M7) (p = 0.0001). The highest colony counts were found for the slime-producing strain on polyethylene and polymethylmethacrylate. The slime-negative mutant lacked the ability of accumulation. Our in-vitro results show the relevance of slime production by S. epidermidis for in-vitro colonisation of biomaterials, with a preference for polyethylene and polymethylmethacrylate.