Antimicrobial binding and growth kinetics in BacT/ALERT® FA Plus and BACTEC® Aerobic/F Plus blood culture media

The capacity of absorbent beads in BacT/ALERT® FA Plus and BACTEC® Aerobic/F Plus blood culture bottles to bind and neutralize antibiotics was compared. Binding was established using reverse-phase HPLC, and inactivation was based on the recovery of susceptible test stains from simulated blood cultures. The FA Plus medium demonstrated more rapid and better overall binding kinetics for each drug tested, resulting in significantly better overall recovery rates. Differences in time to detection favored the FA Plus medium for three drug/organism combinations and Aerobic/F Plus for two.