Analysis of the Staphylococcus aureus Collagen Adhesin B Domain

摘要

Staphylococcus aureus has the capacity to colonize essentially any tissue including bone. The ability to colonize diverse tissues appears to involve bacterial surface proteins (adhesions) that bind specific host proteins. For instance, the ability to bind collagen appears to contribute to the ability to colonize bone and cartilage. Our previous studies suggest the ability to bind collagen is due to the production of a single adhesin encoded by a gene designated cna. Indeed, the only exception to the correlation between the presence of cna and the ability to bind collagen are heavily-encapsulated strains that encode and express cna but do not bind collagen. The fact that non- encapsulated mutants bind collagen suggests that the capsule can mask the adhesin on the surface of S aureus cells. Based on the recognized role of the capsule in the pathogenesis of staphylococcal infections, and the apparent role of the collagen adhesin in musculoskeletal infections, these results present the bacterium with a paradox. Specifically, previous results imply that S. aureus utilizes two virulence factors, one of which (the capsule) is not compatible with the other (the collagen adhesin). That is consistent with our studies demonstrating that heavily-encapsulated strains are particularly virulent in a murine peritonitis model of staphylococcal disease but did not cause disease in a rabbit model of osteomyelitis.