Does in situ replacement of a staphylococcal infected vascular graft with a rifampicin impregnated gelatin sealed Dacron graft reduce the incidence of subsequent infection?
M. Vicaretti et al., Does in situ replacement of a staphylococcal infected vascular graft with a rifampicin impregnated gelatin sealed Dacron graft reduce the incidence of subsequent infection?, INT ANGIOL, 18(3), 1999, pp. 225-232
Background. The aim of this study was to treat methicillin-resistant Staphy
lococcus aureus (MRSA) or S. epidermidis prosthetic vascular graft infectio
ns by in situ replacement with a rifampicin bonded Gelsoft graft.
Methods. Interposition grafts were placed in the internal carotid artery of
56 merino sheep and the graft surface directly inoculated with 10(8) colon
y forming units (CFU) of MRSA (29) or S. epidermidis (27). At three weeks,
grafts were harvested and sheep allocated to three groups. In the MRSA infe
cted group, sheep received grafts soaked in 1.2 mg/ml (12), 10 mg/ml (10) a
nd no (7) rifampicin. For S. epidermidis, sheep received grafts soaked in 1
.2 mg/ml (10), 10 mg/ml (9) and no (8) rifampicin. There were two deaths, i
n the MRSA study group, one each from the rifampicin treated groups. The re
maining sheep were euthanased and grafts harvested three weeks following re
grafting. Grafts at harvests were assessed for perigraft abscess formation,
anastomotic disruption and graft thrombosis. Swabs were taken to assess ba
cterial growth in the perigraft tissues, and external and internal graft su
rfaces. A 3-5 mm segment of graft was incubated in a broth medium. For S. e
pidermidis the remainder of the graft was ground and then incubated in a br
oth medium.
Results. For MRSA, no statistical difference between the groups was reached
for any of the measured parameters. For S. epidermidis, a significant redu
ction was reached for total infected specimens in the 10 mg/ml group compar
ed to both control (p<0.001) and 1.2 mg/ml (p<0.005) groups. Graft reinfect
ion was also less likely to occur with S. epidermidis than MRSA.
Conclusions. In conclusion, replacement of S. epidermidis infected vascular
grafts with 10 mg/ml rifampicin soaked Gelsoft graft is effective in reduc
ing subsequent S. epidermidis infection. This conclusion cannot be extended
to MRSA infected vascular grafts.