Staphylococcus aureus bacteremic pneumonia

Abstract

Staphylococcus aureus bacteremic pneumonia is an uncommon cause of hospitalization, with a high mortality rate. However, published reports are scarce and have included a small number of cases. All patients with S. aureus bacteremic pneumonia were prospectively collected in our institution from 2000 to 2014, and a retrospective revision was performed to identify risk factors associated with methicillin resistance and to update the mortality of this entity. A total of 98 patients were admitted: 57.1 % were due to methicillin-susceptible S. aureus (MSSA) and 42.8 % due to methicillin-resistant S. aureus (MRSA). In 40 patients (40.8 %), the infection was community acquired. Thirteen were ventilator-associated pneumonia episodes. The most frequent comorbidities were chronic lung disease (34.7 %), chronic renal failure (31.6 %), diabetes mellitus (29.6 %), and cardiovascular disease (31.6 %). Septic shock was present in 46 patients (46.9 %). The 30-day mortality was 46.9 %. MRSA infections occurred in older patients, more frequently with cardiovascular diseases, and they had received antibiotic treatment in the previous month more often than MSSA-infected patients. Patients with infection due to MSSA presented more frequently with septic shock, but they received more frequently appropriate empirical antibiotic therapy than patients with MRSA pneumonia (96 % vs. 38.1 %), and no differences in mortality were observed between both groups. In conclusion, S. aureus bacteremic pneumonia is a severe infection that, nowadays, affects people with comorbidities and the mortality is still high.