PROLONGED INCUBATION OF BLOOD AND BONE-MARROW CULTURES IN 12B BOTTLESPROCESSED ON THE BACTEC-460 TB SYSTEM DOES NOT INCREASE MICROBIAL RECOVERY

Standard references continued to recommend testing specimens processed on the BACTEC TB System for 8 weeks, despite evidence that mycobacter ia are rarely recovered beyond 5-6 weeks. To clarify this issue, we re trospectively reviewed all positive blood/bone marrow cultures process ed during a 17-month period when specimens were tested for 6 weeks. We then prolonged the incubation period to 8 weeks during the subsequent 5 months. Excluding Mycobacterium genavense, only 1 of 159 mycobacter ial isolates was recovered during and none were recovered beyond the 5 th week of incubation and testing on the BACTEC TB System. (C) 1996 El sevier Science Inc.