Relevance of routine use of the anaerobic blood culture bottle

Abstract

Using the BacT/Alert automated system, we conducted a 1-year retrospective study on blood cultures, focusing on the relevance of routine use of the anaerobic bottle. The rate of patients with positive blood cultures was 19.7%. Among these, 13.5% had a positive anaerobic bottle in the absence of any aerobic bottle, and 2/3 of these grew with nonobligate anaerobes. These patients were hospitalized in 20 out of 26 wards of the hospital group. For 65.4% of the monomicrobial-positive blood cultures growing Enterobacteriaceae, the anaerobic bottle detected growth earlier than the corresponding aerobic bottle. These data suggest that, in our institution, the use of an anaerobic bottle is still relevant.

FIG. 1.

Rates of positive blood culture bottles. +, positive; −, negative.

FIG. 2.

For monomicrobial blood cultures, difference between time of detection of growth for the anaerobic bottles and their corresponding aerobic bottles for Enterobacteriaceae (A), the Enterococcus/Streptococcus group (B), and S. aureus (C). P values correspond to the chi-square test and were used to determine if the number of aerobic bottles positive before the anaerobic bottle was statistically different from the number of anaerobic bottles positive before the aerobic bottle. The level of statistical significance was set at 0.05.