EVALUATION OF AN EXTENDED BLOOD CULTURE PROTOCOL TO ISOLATE FASTIDIOUS ORGANISMS FROM PATIENTS WITH AIDS

Recent reports of fastidious pathogens suggest the need for special bl ood cultures for immunocompromised patients. Blood cultures from 35 hu man immunodeficiency virus (HIV)-infected patients with unexplained fe ver (greater than or equal to 38.0 degrees C) and CD4 counts of <125 c ells per mm(3) were collected into a vacuum tube with sodium polyaneth olsulfonate, an Isolator tube, and BACTEC aerobic and anaerobic bottle s. Blood from the sodium polyanethosulfonate tube was inoculated into BACTEC 13A bottles, which were read weekly for 16 weeks. Isolator sedi ment was divided among eight agar media, including four sheep blood ag ar media: chocolate agar, brain heart infusion blood agar, heart infus ion blood agar, and brucella blood agar. Other agar plates included Sa bouraud's, buffered charcoal-yeast extract, Middlebrook 7H11 (M7H11) w ith hemoglobin, and M7H11 with mycobactin J. Incubation conditions inc luded air and CO2-enriched aerobic, microaerophilic, and anaerobic atm ospheres. Aerobic BACTEC broths received an acridine orange stain on d ay 8 and were subcultured at 2, 4, and 8 weeks, Anaerobic BACTEC bottl es were subcultured at 4 weeks. All solid media, including subcultures , were incubated for 8 weeks, providing a total of 16 weeks of incubat ion for each specimen. Clinically significant isolates included eight Mycobacterium avium complex isolates and one each of Bartonella hensel ae, Bartonella quintana, Shigella flexneri, Klebsiella oxytoca, and Cr yptococcus neoformans. All isolates were detected with commercially av ailable media and, with the exception of Bartonella spp., were recover ed within incubation times routinely used in most clinical laboratorie s.