Routine use of the BacT/ALERT FAN anaerobic bottle: indicated or not?

Abstract number: p984

Van Meensel  B., Verhaegen  J., Frans  J., Castryck  H., Blanckaert   N.


Traditionally, routine blood cultures for adult patients consist of paired aerobic and anaerobic blood culture bottles. However, expert opinions differ on the routine use of the anaerobic blood culture bottle, debating substitution of the anaerobic bottle by an additional aerobic bottle. In this way, the optimal volume of 20 ml of blood per culture for detecting bacteraemia would be collected. The aim of our study was to evaluate the benefit of routinely using the combination of the BacT/ALERT FAN aerobic and anaerobic bottle in a tertiary care medical centre.


We performed a retrospective study of 11 740 blood culture bottles (5855 paired and 30 unpaired) obtained from 3611 adult patients admitted to the emergency room between January 2005 and August 2005. Statistical analysis using the sign-test was limited to those isolates classified as clinically significant and was only performed when at least 10 isolates per category were recovered.


A total of 325 significant microbial strains were isolated from 312 patients. Analysis of these isolates revealed no significant difference between the yield of the FAN aerobic and FAN anaerobic bottles. However, significantly more Pseudomonas aeruginosa (p < 0.0001) and Streptococcus pneumoniae (p = 0.0156) were recovered from the aerobic bottle, while significantly more strictly anaerobic bacteria (p < 0.0001) and Enterobacteriaceae other than Escherichia coli (p = 0.0156) were recovered from the anaerobic bottle. Twenty-two patients (7.1 %) had a positive blood culture with strictly anaerobic bacteria, which were only recovered from the anaerobic bottles. These were mainly elderly patients, 15 with an abdominal pathology, 3 with neutropenic fever, and 3 with a decubitus ulcer and 1 with a tooth abscess. In two of these 22 patients, the result of the blood culture led to a change in diagnosis and an adjustment of the antibiotic therapy.


Our data suggest that the routine use of the BacT/ALERT FAN anaerobic bottle is still recommended in our institution because we have a relative high proportion of strictly anaerobic bacteraemia and because some facultative organisms apparently grew preferentially in the anaerobic bottle. Furthermore, although infrequently, the knowledge of an anaerobic bacteraemia did influence the management of patients.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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