Comparative recovery of fungi from biphasic and conventional blood culture media

Abstract

A brain heart infusion broth and agar biphasic bottle was compared with a vented broth brain heart infusion bottle for the recovery of fungi from blood. A total of 40 fungi, all yeasts, were recovered from 5,000 blood cultures. The biphasic bottle slightly increased the overall recovery of six species of yeasts. In addition, yeasts were first detected more often in the biphasic bottle (73%) than in the vented broth bottle (38%). A routine early (6- to 24-h) or late (5-day) subculture of macroscopically negative cultures may not be required for yeast isolation when a biphasic medium is used. Of the yeasts initially detected in the biphasic medium, 83% were seen to be growing on the agar slant. Only four were detected from a 24-h subculture, a Candida glabrata of questionable clinical significance, was recovered after our routine blood culture period of 7 days; however, other fungi, not recovered in this study, require extended incubation periods.