Mucin production by Staphylococcus epidermidis. A virulence factor promoting adherence to vascular grafts
D. D. Schmitt, D. F. Bandyk, A. J. Pequet, M. A. Malangoni and J. B. Towne
The production of an exopolysaccharide (mucin) by some Staphylococcus
epidermidis strains facilitates bacterial adhesion to prosthetic vascular
grafts and may play an important role in adherence-mediated growth. An in
vitro model was developed to measure the differential adherence of
mucin-producing (RP-12) and nonmucin-producing (SP-2) S epidermidis strains
onto expanded polytef and velour knitted Dacron graft material. After
incubation in a 10(7)/mL suspension of organisms, graft specimens were
repeatedly washed to remove nonadherent organisms and then sonicated to
dislodge adherent organisms. Bacterial adherence was calculated from a
quantitative culture of the sonication effluent. Both S epidermidis strains
adhered in ten to 100 times greater numbers to the knitted Dacron graft
material than to expanded polytef. The production of an exopolysaccharide
by the RP-12 strain significantly increased adherence to both graft types
compared with the SP-2 strain. The increased adherence of the RP-12 strain
was inhibited by adding D-mannosamine to the inoculum. The in vitro model
developed is well suited for further study of the mechanisms by which
bacteria adhere to and colonize vascular grafts.
