Controlled Clinical Comparison of BacT/Alert FA Plus and FN Plus Blood Culture Media with BacT/Alert FA and FN Blood Culture Media

New blood culture media containing antibiotic-binding polymeric beads have been developed for the BacT/Alert (bioMérieux, Inc., Durham, NC) blood culture system. To assess the performance of these new media, we compared the new BacT/Alert aero-bic medium (FA Plus) with resins to BacT/Alert FA medium with activated charcoal and the new BacT/Alert anaerobic medium (FN Plus) to BacT/Alert FN medium at 3 tertiary care medical centers. Study bottle pairs were inoculated with a target volume of 6 to 10 ml of blood from adults and incubated in the BacT/Alert 3D blood culture instrument. In the FA Plus versus FA compari-son, there were 1,507 study pairs. Among 170 isolates causing true bloodstream infections (BSIs), significantly more Staphylo-coccus aureus (P< 0.001) and total microorganisms (P< 0.01) grew in the FA Plus bottle than in the FA bottle. Fewer coagulase-negative staphylococcal (CoNS) contaminants grew in the FA Plus bottle than in the FA bottle (10 versus 22; P 0.05). In addition, growth was detected earlier in the FA Plus bottle than in the FA bottle (P< 0.001). In the FN Plus versus FN compari-son, there were 2,386 study pairs. Among 201 isolates causing true BSIs, significantly more S. aureus (P< 0.001), CoNS (P< 0.005), and total microorganisms (P< 0.001) grew in the FN Plus bottle than in the FN bottle. Also, significantly more CoNS contaminants grew in the FN Plus bottle than in the FN bottle (P< 0.001). Overall, microorganisms were detected earlier in the FN Plus than in the FN bottle (P< 0.001). Medical technologists at all 3 study sites preferred the new media for Gram stain inter-pretation. We conclude that the FA Plus and FN Plus media provide improved and earlier detection of microorganisms com-pared with the FA and FN media and are preferable for Gram stain interpretation as well