Comparative evaluation of the diffusion of tobramycin and cefotaxime out of antibiotic‐impregnated polymethylmethacrylate beads

Abstract

Both tobramycin and cefotaxime diffuse from antibiotic‐impregnated polymethylmethacrylate (PMMA) beads in quantities sufficient to inhibit the growth of bacteria on agar lawns or in broth cultures over a 28‐day period. Extraction of antibiotic from tobramycin or cefotaxime‐impregnated PMMA beads revealed that substantial amounts of both antibiotics remained within the beads despite 28 days of diffusion. Diffusion of antibiotic from the PMMA beads during the initial 3–5 days is much greater than occurs for the remainder of the 4‐week period. The results of the study suggest that perhaps tobramycin or cefotaxime‐impregnated PMMA beads would produce local levels of antibiotic high enough to sterilize a given dead space for a period of 28 days.