The judicious use of perioperative
antibiotic prophylaxis reduces the infectious complications of surgery. However, increased bacterial resistance within hospitals may make
antibiotic prophylaxis less effective in the future and alternative strategies are needed. New
immunomodulatory agents might prevent
wound infections by stimulation of the host immune system. To test this hypothesis, we administered poly-[1-6]-beta-D-glucopyranosyl- [1-3] -beta-D-glucopyranose
glucan (
PGG glucan), which enhances neutrophil microbicidal activity, intravenously to guinea pigs in doses ranging from 0.015 to 4 mg/kg of
body weight on the day before, on the day of, and on the day after intermuscular inoculation with methicillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis.
Abscesses were identified at 72 h, and median infective doses (ID50) and statistical significance were determined by logistic regression. Guinea pigs receiving
PGG glucan and inoculated with methicillin-resistant S. aureus and S. epidermidis exhibited ID50 of as much as 2.5- and 60-fold higher, respectively, than those of control guinea pigs not receiving
PGG glucan. Maximal protection was observed with a dose of 1 mg of
PGG glucan per kg, and efficacy was reduced at higher as well as at lower
PGG glucan doses. Furthermore, a single dose of
PGG glucan given 24 h following bacterial inoculation was found to be effective in preventing
infection. We conclude that
PGG glucan reduces the risk of staphylococcal
abscess formation. Neutrophil-activating agents are a novel means of prophylaxis against surgical
infection and may be less likely than
antibiotics to be affected adversely by the increasing antibiotic resistance of nosocomial pathogens.