Staphylococcus aureus bacteremia in patients with hematologic malignancies: a retrospective case-control study

Staphylococcus aureus bacteremia (SAB) continues to be a major problem related to both community and nosocomially acquired infection. Nevertheless few data are presently available in literature about this infection in patients with hematologic malignancies.

The purpose of this retrospective study was to report further data on the clinical characteristics and outcome of patients with SAB. All episodes of SAB occurring between January 1997 and June 2001 were identified and defined by analysis of the patients' clinical records.

The nosocomial mortality rate was only 3.5% and no patient developed secondary complications. Comparison between neutropenic hematologic patients with SAB and neutropenic hematologic patients with Gram-negative bacteremia (GNB) revealed an higher mortality in the latter group (p=0.03); furthermore, severe sepsis and septic shock were more frequent in patients with GNB (p<0.001). Comparison between neutropenic patients with hematologic malignancies and non-neutropenic ones with other underlying diseases revealed significantly higher morbidity and mortality rates in the latter group. Non neutropenic patients seemed to be more susceptible to both early complications, such as severe sepsis or septic shock (p=0.002) and to later ones, such as endocarditis and metastatic abscesses (p=0.02).

Our results seem to suggest that SAB in patients with hematologic malignancies is often a low inoculum infection associated with negligible morbidity and mortality rates, especially when adequate antistaphylococcal therapy is administered promptly.