Effectiveness of antibiotic removal by the antibiotic-binding blood culture systems

Abstract

The effectiveness of antibiotic removal by the BACTEC aerobic resin-containing blood culture medium (16B) and the Antimicrobial Removal Device (ARD) was compared for 12 antibiotics: ampicillin, cephalothin, cefoperazone, cefotaxime, moxalactam, nafcillin, gentamicin, tobramycin, azlocillin, mezlocillin, piperacillin, and ticarcillin. The ability to recover eight commonly encountered species of bacteria from antibiotic-containing serum by these two systems showed that recovery of antibiotic-exposed bacteria was dependent not only upon the amount and rate of the antibiotic removal but also upon the kinetics of bacterial killing by the anti-biotic(s). The 16B medium had difficulty recovering organisms exposed to ticarcillin and moxalactam, whereas the ARD had difficulties with moxalactam and sometimes with cefotaxime and cefoperazone. Although neither system was able to recover all species of microorganisms tested, these in vitro results suggest that to use optimally these new culture systems, knowledge of the suspected pathogen(s), the amount and kind of antibiotic(s) administered, and the rate of bacterial killing by the antibiotic(s) is required.