Optimizing detection of microbial sepsis: A Comparison of Culture Systems Using Packaged Sets with Directions for Blood Collection

Abstract

Detection of microbial sepsis is an important aspect of medical practice. To facilitate the recovery of bacteria and fungi we evaluated 10,933 complete blood culture sets integrating the automated ESP system (Difco) with a manual system using the Isolator (Wampole) and Thiol broth bottle (Difco). To improve compliance with the recommended procedure for submitting specimens, we packaged the three components as a unit that included brief instructional material. A three-component (one ESP bottle, one Thiol bottle, and one Isolator tube) package containing specific instructions was used. The aerobic ESP performance was compared with the Isolator, and the anaerobic ESP with the Thiol bottle. A hypothetical assessment involving all three components was also made. The cultures were processed under routine laboratory conditions. Charts were reviewed from specimens with discrepant results to ascertain true positives versus contaminant cultures in the discordant culture sets. There were 896 organisms recovered from 393 patients. Of these, 421 were in the aerobic compared with 475 in the anaerobic portion of the study. ESP enhanced the recovery of Streptococcus pneumoniae ( P < .05). The Isolator was superior for the recovery of yeasts (.05 < P < .1). Using the packaged system, the compliance rate for complete three-component culture sets was 95.2%, with a 34.4% resultant increase in positive blood cultures from only a 5.7% increase in sets. Packaged culture media including instructions enhance appropriate collection of complete sets, increase the number of recovered organisms, and improve medical practice.