title: Advantage of combining resin with lytic BACTEC blood culture media.
abstract: The BACTEC 9240 (Becton Dickinson, Sparks, Md.) automated blood culture system is based on 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 anaerobic/F. Sets of Plus aerobic/F and Lytic anaerobic/F vials inoculated with similar volumes (9 +/- 2.5 ml) were evaluated. In the laboratory, the vials were introduced into the system in accordance with the recommendations of the manufacturer and incubated at 35 degrees C for 5 days. A total 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 (P = 0.05), Pseudomonas spp. (P < 0.0001), other gram-negative bacteria (P = 0.004), and yeasts (P < 0.0001) were isolated from Plus aerobic/F medium, but more streptococci (P < 0.0001), E. coli (P = 0.02) strains and anaerobes (P < 0.0001) were detected with Lytic anaerobic/F medium. Lytic anaerobic/F vials were 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.
authors.affiliation: Laboratoire Central de Bactériologie, Hôpital Cantonal de Genève, Geneva, Switzerland. Peter.Rohner@hcuge.ch
authors.forename: P
authors.initials: P
authors.lastname: Rohner
authors.forename: B
authors.initials: B
authors.lastname: Pepey
authors.forename: R
authors.initials: R
authors.lastname: Auckenthaler
mesh_terms: D000328:Adult; D000332:Aerobiosis; D000693:Anaerobiosis; D016470:Bacteremia / Q000175:diagnosis; D001769:Blood; D003470:Culture Media; D016469:Fungemia / Q000175:diagnosis; D006801:Humans; D008828:Microbiological Techniques / Q000295:instrumentation*; D012116:Resins, Plant; D018805:Sepsis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors
chemical_list: D003470:Culture Media; D012116:Resins, Plant