Advantage of combining resin with lytic BACTEC: Blood culture media

The BACTEC 9240 (Becton Dickinson, Sparks, Md.) automated blood culture system is based an the continuous monitoring of CO2 production by means of a fluorescent sensor attached to the bottom of a culture vial, We compared two media for this System, resin-containing Plus aerobic/F and Lytic anaeaobic/F, Sets of Plus aerobic/F and Lytic anaerobic/F vials inoculated with similar volumes (9 +/- 2.5 mi) mere evaluated, In the laboratory, the vials mere introduced into the system in accordance with the recommendations of the manufacturer and incubated at 35 degrees C for 5 days, A tot-al of 10,914 sets consisting of two bottles each were obtained from 3,674 patients (2.97 cultures per patient), Of these, 1,233 (11%) were culture positive, including 1,074 (10%) yielding at least one pathogen, and 178 (2%) were contaminated. A total of 1,135 isolates were considered clinically relevant in 624 septic episodes; we isolated 894 from Plus aerobic/F and 852 from Lytic anaerobic/F (P = 0.06 [not significant]). More S. aureus isolates (II = 0.05), Pseudomonas spp, (P < 0.0001), other gramnegative bacteria (P = 0.004), and yeasts (P < 0.0001) were isolated from Plus aerobic/F medium, but more streptococci (P < 0.0001), E. call (P = 0.02) strains and anaerobes (P < 0.0001) were detected with Lytic anaerobic/F medium, Lytic anaerobic/F vials mere significantly (P < 0.0001) more often positive at least 6 h before Plus aerobic/F vials (n = 112 versus 52, respectively), Significantly more (P < 0.0001) Plus aerobic/F vials (n = 210; 1.9%) than Lytic anaerobic/F vials (n = 42; 0.4%) were unconfirmed positives, Plus aerobic/F and Lytic anaerobic/F proved to be a valuable pair of blood culture media, Plus aerobic/F performs better for patients under antibiotic treatment, due to the antimicrobial-neutralizing effect of resins, For patients without antibiotic therapy, more microorganisms could be isolated from Lytic anaerobic/F due to cell lysis.