In vitro efficacy of newly designed vancomycin-based microparticles.

Purpose: To compare the in vitro bactericidal and anti-adhesion properties of vancomycin-based microparticles and lyophilized vancomycin and estimate their relevance to perioperative antibiotic prophylaxis and endophthalmitis prevention.

Setting: University research laboratory, Lyon, France.

Methods: The bactericidal and anti-adhesion properties of a newly designed drug-delivery system were assessed on Staphylococcus epidermidis clinical strain N890074 containing the intercellular adhesion locus ica. Lyophilized vancomycin at 20 mug/mL was used as a standard. The new drug-delivery system, designed for the study, consisted of sterile, biocompatible, and biodegradable microparticles with continuous release of vancomycin. To obtain bacterial killing and anti-adhesion curves, experiments were first performed in a bacterial suspension containing 1000 colony-forming units per milliliter. Experiments were then performed with intraocular lenses incubated in the suspension. Efficacy was investigated by bacterial counts and scanning electron microscopy observations.

Results: The bactericidal and anti-adhesion effects of vancomycin-based microparticles started after 3 hours (P<.002) and 1 hour (P<.001), respectively, and of lyophilized vancomycin, after 1 hour (P = .004) and 1 hour (P<.001), respectively. There was no difference between the 2 forms of vancomycin in the bactericidal effect starting at 21 hours and the anti-adhesion effect starting at 6 hours (P>.05).

Conclusions: The newly designed vancomycin-based microparticles showed relevant antibacterial and anti-adhesion properties after releasing a sufficient antibacterial quantity, proving that vancomycin remains efficient after undergoing the encapsulation process.