Retrospective analysis of two hundred and twelve cases of bacteremia due to anaerobic microorganisms

Abstract

Cases of bacteremia caused by anaerobic microorganisms and occurring during a four year period in a non-selected patient group in a Spanish general hospital were analysed retrospectively. Microbiological data was collected on 212 patients and clinical data on 103 patients. Cases of anaerobic bacteremia represented 8.6% of the total number of cases of bacteremia. Of the 232 anaerobic microorganisms causing bacteremia, gram-negative bacilli were responsible in 113 cases (48.7%), gram-positive bacilli in 92 cases (39.6%), gram-positive cocci in 25 cases (10.7%), and Veillonella spp. in two cases (0.8%). The most important clinical features were fever (64%), anemia (56%), septic shock (22%) and metastatic abscesses (21%). Patients with anaerobic bacteremia were hospitalized for an average of 51.7 days. The overall mortality was 32% and factors associated with poor prognosis were severe underlying disease, nosocomial acquisition, presence of shock, presence of metastatic foci of infection, and absence of adequate surgical drainage. The mortality rate of patients who received adequate antimicrobial therapy was 30% and that of patients who received inadequate treatment or none was 29%. It is concluded that anaerobic bacteremia has a significant rate of morbidity and mortality and that underlying disease and surgical debridement and/or drainage have greater prognostic significance than the use of antimicrobial agents.

Clinical significance of anaerobic bacteremias in a general hospital

“…The most frequent route of entry was intraabdominal; microorganisms entered via the gastrointestinal, female genital or urinary tract in 50% of our patients, a finding also reported by other authors [5,19,26]. The higher percentage of community-acquired bacteremias than in other studies [5,26] may be related to differences in patient samples, depending on the type of medical care facility studied and to the use of antibiotics for out-patient treatment, for which agents with anti-anaerobic activity are rarely prescribed.…”

“…Clostridium perfringens and Peptococcus [5,11,19,21,26]. As in other series, 64% of our patients had a rapidly or eventually fatal underlying disease [5,13,19,26].…”

“…These figures are lower than those found in Spain in 1985 by other authors, who reported frequencies of 5.6% and 8.6% and an incidence of 2.9 episodes per 1000 patients [5,26]. However, our data are similar to those in a recent study conducted in two American hospitals, which yielded incidences of 0.54 and 0.86 episodes per 1000 patients, and frequencies of blood cultures positive for anaerobes of 1.8% and 3.2% [i9].…”

“…As in other series, 64% of our patients had a rapidly or eventually fatal underlying disease [5,13,19,26]. Although anaerobic bacteremia has been documented in all age groups, it is greater in patients older than 60 years [24], as was the case in the present series.…”

“…All patients underwent physical examination upon admission to hospital, on day 3 of their stay, at the end of treatment, and upon discharge, with particular attention to fever, tachycardia or other complications. Shock, disseminated intravascular coagulations, respiratory distress and metastases were assessed on the basis of published criteria [5]. Laboratory tests were done periodically, and consisted of complete blood count, coagulation tests, general biochemical tests (Hitachi SMAC-24), and trace elements in urine.…”