Anaerobic Blood Cultures Revisited – AGAIN?

In many microbiology laboratories a blood culture consists of an aerobic bottle and an anaerobic bottle which is considered a blood culture “set. ” The third edition of Clinical Microbiology Procedures Handbook still mentions the aerobic/ anaerobic blood culture set. Cumitech Blood Cultures IV makes no specific recommendations on which bottles should be used. Since the early 1990s there have been many evaluations of the utility of the anaerobic bottle in the blood culture set and results have varied widely. In 1992, Dr. Patrick R. Murray, a well-known and respected blood culture expert, published a study which concluded that “…bacteremia caused by obligate anaerobic bacteria is decreasing relative to sepsis caused by other bacteria and fungi and that the routine use of unvented anaerobic blood culture bottles reduces the recovery of common aerobic blood-stream pathogens.”1 The study does not mention whether they dropped the anaer-obic bottle in favor of a second aerobic one, but it did warn that other hospitals may not experience the same results and encouraged each lab to examine its own experience and weigh the advantages and disadvantages of using the anaerobic bottle. In 2003, Dr. Paul Bourbeau com-pared the recovery of isolates from two aerobic bottles (BacT/ALERT® FAN®, bioMérieux Corp.) versus an aerobic/anaerobic paired set (BacT/ALER