Retrospective comparison of three blood culture media for the recovery of yeasts from clinical specimens

Abstract

In a retrospective fashion, two different blood culture bottles with biphasic brain heat infusion media, one permanently and the other transiently vented, were compared to a transiently vented tryptic soy broth blood culture bottle for the recovery of yeasts from blood. A total of 95 isolates ofCandida species and 19 isolates ofCryptococcus neoformans were recovered, of which 95 % were from the permanently vented biphasic medium bottle incubated at 30 °C, 57 % were from the transiently vented biphasic medium bottle incubated at 35 °C, and 45 % were from the transiently vented tryptic soy broth bottle incubated at 35 °C. In 81 % of the patients with candidemia, yeasts were detected either only (50 %) or earlier (31 %) in the permanently vented biphasic blood culture bottle. The mean recovery time was shorter in both biphasic media compared to the tryptic soy broth bottle.Cryptococcus neoformans was not recovered from the transiently vented broth, and less than 50 % of the isolates ofCandida glabrata andCryptococcus neoformans grew in the transiently vented biphasic bottle. The results suggest that when fungemia is suspected, the use of a permanently vented biphasic bottle incubated at 30 °C will increase the recovery rate of yeasts from blood and that the transiently vented biphasic bottle and tryptic soy broth bottle are less satisfactory for this purpose.