Investigation of the risk factors of anaerobic bacteremia in a case-control study.

Background: Many case series studies have reported risk factors of infection with anaerobic bacteria, but few factor analysis studies have been conducted.

Objective: We conducted a case-control study to identify the risk factors of anaerobic bacteremia.

Methods: We compared a number of characteristics of patients with anaerobic bacteremia with those with aerobic bacteremia. Clinical information for 71 patients of anaerobic bacteremia was collected from January 1999 to December 2012 in Aichi Medical University Hospital. For each case, we identified up to four controls matched by the time of the positive blood culture.

Results: Multivariate logistic analyses revealed an association between anaerobic bacteremia and malignancy (OR: 3.35, 95% CI: 1.85-6.09), Douglas' pouch drains (OR: 25.90, 95% CI: 2.90-25.00) and chest drains (OR: 3.35, 95% CI: 1.19-9.43) as the primary causative disease, as well as associations between anaerobic bacteremia and the gastrointestinal tract (OR: 3.29, 95% CI: 1.38-7.81), genitourinary tract (OR: 4.98, 95% CI: 2.06-12.05), Douglas' pouch drains (OR: 16.95, 95% CI: 1.82-166.67) and chest drains (OR: 3.62, 95% CI: 1.29-10.20) as the primary causative organs. On the other hand, our study showed that having a central venous catheter was not associated with anaerobic bacteremia.

Conclusions: We demonstrated an association between anaerobic bacteremia and malignancy, gastrointestinal and genitourinary tracts, patients having a Douglas' pouch drains or chest drains. These findings may be useful for developing early appropriate management for anaerobic bacteremia.