[Methicillin susceptible Staphylococcus aureus bacteremia: epidemiology and prognostic factors. A prospective study...

Staphylococcus aureus bacteremia continues to be a major problem in hospitals due to its high prevalence, severity and treatment difficulties. This study aimed to evaluate epidemiological and clinical features, risk factors and influence of antibiotic choice in outcome and mortality in patients with methicillin susceptible S. aureus bacteremia (SAMSB).

A prospective, observational study of inpatients with SAMSB (2000-3).

A total of 131 with SAMSB were included (mean age 56 years; 58% > or = 60 year-old); 56.5% were due to nosocomial bacteremia; 46% of all patients had an underlying condition (diabetes mellitus being the most frequent [28%]); a risk factor for bacteraemia was identified in 98% (intravenous catheter: 72%). Mortality rate was 16% (21/131). Comparative analysis according to nosocomial or community acquisition showed that the former was more frequent in Surgical Wards, patients with intravenous or urinary catheters, traumatic patients, dialysis and ICU patients. Initial severity and mortality were highest in community-acquired SAMSB. In multivariate analysis, risk factors associated with higher mortality were: presence of an ultimately or rapidly fatal underlying disease, acute severity of illness at onset and inadequate empirical treatment.

SAMSB is a clinically severe infection that occurs in patients with baseline disease, especially diabetics, that is almost always related to predisposing risk factors (mainly intravenous catheters). In the presence of a serious baseline disease, the initial critical clinical condition and inadequate empirical treatment are the main prognostic factors associated to greater mortality.