Real-life evaluation of supplemental anaerobic blood culture bottles: impact on diagnosis and therapeutic management of patients with suspected sepsis.

OBJECTIVE

To evaluate the impact of the systematic inclusion of anaerobic blood culture bottles, in conjunction with aerobic bottles, in the diagnosis and management of patients with suspected sepsis, analyzing their effect on pathogen detection, time to positivity, and subsequent therapeutic modifications.

METHODS

A cross-sectional observational study was conducted involving 565 patients weighing 36 kg or more with suspected bacteremia or fungemia. Two sets of blood culture bottles were collected per patient (each set consisting of one aerobic and one anaerobic bottle), with at least one bottle flagged as positive by the detection system. Samples were processed using the BACT/Alert VIRTUO automated system, and microorganisms were identified via MALDI-TOF VITEK MS mass spectrometry. Isolates and time to positivity were compared between both bottle types.

RESULTS

Of the total pathogenic microorganisms recovered (n = 498), 56.4% were isolated in both bottle types, 26.9% exclusively in aerobic bottles, and 16.7% solely in anaerobic bottles. Most isolates recovered exclusively from anaerobic bottles were identified as facultative anaerobes. No statistically significant differences were found in time to positivity between aerobic and anaerobic bottles (p > 0.05). In 50.5% of patients with exclusive isolates in anaerobic bottles, a documented change in antimicrobial therapy was observed.

CONCLUSION

The routine incorporation of anaerobic blood culture bottles enhances the recovery of pathogenic microorganisms, particularly facultative anaerobes, without increasing contamination rates or detection time. These findings support the systematic inclusion of anaerobic bottles in blood culture protocols for patients with suspected sepsis, contributing to the optimization of microbiological diagnosis and clinical decision-making.