Quorum sensing is a mechanism through which a bacterial population receives input from neighboring cells and elicits an appropriate response to enable survival within the host. Inhibiting quorum sensing by
RNAIII-inhibiting peptide (RIP) has been demonstrated as a very effective mode of prevention and
therapy for device-associated
staphylococcal infections and was tested here for healing of
wounds that are otherwise resistant to conventional
antibiotics.
Wounds, established through the panniculus carnosus of BALB/c mice, were inoculated with 5 x 10(7) CFU of methicillin-resistant Staphylococcus aureus. Mice were treated with
Allevyn, RIP-soaked
Allevyn (containing 20 microg RIP), daily intraperitoneal
teicoplanin (7 mg/kg of
body weight),
Allevyn and
teicoplanin, and RIP-soaked
Allevyn and daily intraperitoneal
teicoplanin. The main outcome measures were quantitative bacterial culture and histological examination with assessment of microvessel density and of
vascular endothelial growth factor (
VEGF) expression in tissue sections. Treatment with RIP-soaked
Allevyn together with
teicoplanin injection greatly reduced the bacterial load to 13 CFU/g (control untreated animals had 10(8) CFU/g bacteria). All other treatments were also significantly effective but only reduced the bacterial load to about 10(3) CFU/ml. Histological examination indicated that only treatment with RIP-soaked
Allevyn with
teicoplanin injection restored epithelial, granulation, and
collagen scores, as well as microvessel density and
VEGF expression, to the levels found with uninfected mice. In conclusion, we observed that RIP may be useful for the management of infected
wounds and that it could represent an exciting and future alternative to the conventional
antibiotics, at present considered the gold-standard treatments for methicillin-resistant S. aureus
infections.