Resin versus Standard Blood Culture Media Used with the New BACTEC Automated Infrared System: An Evaluation in Febrile Granulocytopenic Patients

Abstract

Resin-containing aerobic and anaerobic blood culture media (NR 16A and NR 17A) for use with the new BACTEC infrared blood cultures system were compared with standard BACTEC media (NR 6A and NR 7A) in their efficacy to detect bacteremia in febrile granulocytopenic patients receiving antimicrobial treatment. A total of 1185 sets of blood cultures obtained from 341 patients during a 12-month period were evaluated. There were 109 positive cultures (9.2%) with 128 pathogenic organisms isolated from 52 patients (15.2%). Statistically significant differences were found between aerobic media, but not between anaerobic media. Aerobic resin bottles (NR 16A) were more often positive (90 versus 78, p less than 0.05) than standard aerobic bottles (NR 6A). They yielded a higher number of microorganismS (98 versus 80, p less than 0.05) per culture and per culture-positive patient (53 versus 42, p less than 0.01). NR 16A cultures also were more often positive after 1-day incubation (44% versus 21%, p less than 0.01) than NR 6A cultures and allowed earlier subcultivation. The use of NR 16A medium instead of resin-free aerobic NR 6A medium may enhance the detection of bacteremia in selected groups of patients receiving antimicrobial treatment, and can shorten the time until detection of bacteremia.