Comparative recovery of microorganisms from BacT/ALERT plastic and glass FA and FN blood culture bottles.

bioMerieux, Inc., has recently introduced plastic bottles to replace glass bottles for use in the BacT/ALERT blood culture system. We compared the performance of the plastic to the glass bottles in a large clinical evaluation. Two blood cultures were collected from each patient, one using glass FA (aerobic) and FN (anaerobic) bottles and one using plastic FA and FN bottles. Of the 4,040 sets of four bottles collected, 3,110 contained the recommended 8 to 12 ml of blood, yielding 524 microorganisms with 359 judged to be clinically significant. Of the 359 significant organisms, 255 were recovered in either one or two bottles from both pairs of bottles in a set while 56 organisms were recovered only from the glass bottles and 48 were recovered only from the plastic bottles (P, not significant [NS]). Of the 286 significant organisms recovered only in the FA bottles (glass and plastic), 180 were recovered in both bottles, 57 in the plastic bottles only, and 49 in the glass bottles only (P, NS). Of the 303 significant organisms recovered in the FN bottles only (glass and plastic), 212 were recovered in both bottles, 46 in the plastic bottles only, and 45 in the glass bottles only (P, NS). For individual organisms, the only significant difference in recovery was obtained for Escherichia coli, with more isolates recovered in the FN plastic than in the FN glass bottles (P = 0.02). These data suggest that recovery of microorganisms with plastic FA/FN bottles is at least equal to that with glass FA/FN bottles while offering greater safety for users.