Utility of anaerobic blood cultures in the clinical management of infectious patients

Paired aerobic/anaerobic cultures are routinely performed for the diagnosis of bacteraemia. This study aimed to assess the utility of anaerobic cultures in the management of infectious patients. All positive blood cultures taken from adult patients in a French hospital between November 2018 and March 2020 were evaluated. Clinical and microbiological data were collected for all patients with a positive anaerobic culture. Among the 17,272 positive pairs, 1402 included an anaerobic culture (8 %). In the 487 patients with anaerobic bacteraemia, the most commonly detected microorganisms were Enterobacterales (45 %), Staphylococcus aureus (16 %) and obligate anaerobes (6 %). In the 30 patients with obligate anaerobic bacteraemia, the most commonly detected bacterial species were Bacteroides spp. (30 %). When the bacteraemia-causing microorganism grew in both cultures (76 %), the anaerobic culture became positive prior to the aerobic culture in 54 % of cases-mainly for Enterobacterales and S. aureus. Our findings support the utility of performing anaerobic cultures.