Incidence and clinical significance of anaerobic bacteraemia in cancer patients: a 6-year retrospective study

Recent studies have shown that anaerobes account for 0.5-9% of all episodes of bacteraemia in hospitalised patients, with variations according to geographical location and demographic characteristics, most notably age, but few data are available for cancer patients. This study investigated retrospectively the incidence of anaerobic bacteraemia in cancer patients who received non-surgical treatment over a 6-year period at a tertiary oncology centre. Gastrointestinal (27%) and haematological (29%) malignancies were the most common underlying diseases. Among 45 isolates of anaerobic bacteria recovered from 45 patients, Bacteroides spp. and Clostridium spp. were the most frequent pathogens (60% and 22%, respectively). Twenty episodes of bacteraemia were polymicrobial, most frequently with aerobic Gram-negative bacilli (18 cases). The mortality rate for patients with adequate antimicrobial therapy from the outset was 14%, compared with 63% for patients who were not treated adequately at any time.