Detection of yeast septicemia by biphasic and radiometric methods.

From January 1977 to April 1980 our microbiology laboratory used a commercial biphasic brain heart infusion vented culture method for fungal blood cultures and a commercial radiometric (BACTEC 460, Johnson Laboratories, Cockeysville, Md.) method for bacterial blood cultures. A total of 668 biphasic fungal blood cultures were processed, of which 30 grew yeasts from 19 patients. There were 38,324 BACTEC blood cultures processed for bacteria, of which 184 grew yeasts from 85 patients. The overall detection time for all yeasts averaged 8.3 days for the biphasic method and 2.4 days for the radiometric method. The BACTEC aerobic bottle detected over six times as many yeasts as did the anaerobic bottle. Candida albicans was the most frequently isolated yeast in both methods, being detected in an average of 7.7 days in the biphasic method and 1.6 days in the aerobic BACTEC bottle. It is concluded from this study that the radiometric method is far superior to the biphasic method, because (i) it has a shorter detection time, (ii) it can be used simultaneously with bacterial methods, saving blood and money, and (iii) it requires no special or separate media or instructions for yeasts, thus alleviating confusion in the blood collection process.