Controlled comparison of original vented aerobic FAN medium with new nonvented BacT/ALERT FA medium for culturing blood

To evaluate the performance of BacT/ALERT FA (FA) medium, a new aerobic Bac T/ALERT FAN (FAN) medium (Organon Teknika Corporation, Durham, N.C.) that d oes not require the added cost and inconvenience of a venting unit, we inoc ulated blood specimens from adult patients with suspected sepsis into an or iginal FAN aerobic culture bottle and an FA bottle. Of 7,745 blood culture sets containing both bottles, 5,256 (68%) met the criteria for adequacy of filling. A total of 466 isolates judged to represent the causes of true inf ections were recovered from 276 patients; 271 isolates were recovered from both bottles, 82 were recovered from the FAN bottle only, and 113 were reco vered from the FA bottle only (P < 0.05). More Burkholderia cepacia isolate s (P < 0.01), Candida albicans isolates (P < 0.001), Cryptococcus neoforman s isolates (P < 0.01), yeasts overall (P < 0.001), and total microorganisms (P < 0.05) were recovered from FA bottles. Of cultures found to be positiv e within the first 72 h of incubation, the mean times to detection were alm ost identical for FAN (20.4 h) and FA (20.7 h) bottles. Of 263 isolates tha t caused monomicrobic episodes of bloodstream infections, 180 were detected in both bottles, 32 were detected in FAN bottles only, and 51 were detecte d in FA bottles only (P < 0.05). Of 186 isolates considered to be contamina nts, 63 were detected in both media, 64 were detected in FAN bottles only, and 59 were detected in FA bottles only (P was not significant). The number of false-positive results were comparable: 69 (1.3%) in FAN bottles and 56 (1.1%) in FA bottles. However, there were 14 isolates with false-negative results (6 yeasts, 6 nonfermenters, and 1 isolate each of Propionibacterium acnes and coagulase-negative staphylococci) in FAN bottles, whereas there were none in FA bottles. On the basis of these results, we conclude that th e new nonvented FA bottle is superior to the original vented FAN medium for the recovery of B. cepacia and yeasts, especially C. albicans and C. neofo rmans, and is comparable to FAN medium for other microorganisms.