Anaerobic bacteremia in a cancer center

Seventy-five episodes of clinically relevant anaerobic bacterial bacteremia observed in cancer patients were reviewed. Gastrointestinal (22.7%), hematological (22.7%) and female genital tract (18.6%) cancers were the most common underlying malignant diseases. Among 84 strains of strict anaerobic bacteria recovered in the 75 patients, gram-negative rods were isolated in 49 patients (58.3%), gram-positive rods in 29 patients (34.5%) and gram-positive cocci in 6 patients (8%). Bacteroides spp. and Clostridium spp. were the most frequent pathogens (85.7%). Twenty-one episodes of bacteremia were polymicrobial, aerobic gram-positive cocci being the most frequently associated pathogens. When identified, the primary sites were the gastrointestinal tract (40%), the female genital tract (17.3%), skin and soft tissue (14.6%), the oropharynx (12%) and the lower respiratory tract (6.7%). The source remained unknown in 7 cases (9.3%). The overall survival (evaluated 10 days after the occurrence of bacteremia) was 82.5%. There was no difference in mortality between patients with monomicrobial and polymicrobial bacteremia. Pulmonary complications were more frequent in patients with fatal outcome in comparison to patients who survived. The mortality rate of the patients adequately treated was 10.3% compared to 41% for the patients not treated or treated inadequately (P = 0.016, chi 2).