Clinical spectrum of ventilator-associated pneumonia caused by methicillin-sensitive Staphylococcus aureus

Clinical spectrum of ventilator-associated pneumonia caused by methicillin-sensitive Staphylococcus aureus.Bergmans D, Bonten M, Gaillard C, de Leeuw P, van Tiel F, Stobberingh E, van der Geest S.Department of Internal Medicine, University Hospital Maastricht, The Netherlands.The incidence of tracheal colonization and its association with ventilator-associated pneumonia caused by methicillin-sensitive Staphylococcus aureus (MSSA) was studied prospectively in 530 consecutively admitted mechanically ventilated patients in a general intensive care unit. Furthermore, the clinical spectrum, outcome, and microbiological results of 27 cases of staphylococcal ventilator-associated pneumonia (SVAP) were examined. Ventilator-associated pneumonia was diagnosed by protected specimen brush and/or bronchoalveolar lavage. On admission, 7% of the patients were colonized with MSSA in the trachea. Acquired tracheal colonization was demonstrated in 10% of the patients and occurred less frequently in patients with a hospital stay of > 48 h before ICU admission compared to patients admitted directly to the ICU (6% vs. 15%, p < 0.001). Moreover, colonization was acquired more frequently among trauma and neurological/neurosurgical patients (22%) as compared to surgical and medical patients (7%) (p < 0.0001). Twenty-one patients (4%) developed SVAP, the incident being higher in patients colonized in the trachea with MSSA than in those not colonized (21% vs. 1%), p < 0.00001). Staphylococcal ventilator-associated pneumonia developed more often in trauma and neurological/neurosurgical patients as compared to surgical and medical patients (8% vs. 3%, p < 0.05). Moreover, patients with a hospital stay of < 48 h before admission to the ICU had a higher incidence of SVAP as compared to those with a longer hospital stay before ICU admission (7% vs. 2%, p < 0.01). Crude infection-related mortality was 26%. Preceding colonization with MSSA in the trachea appears to be an important risk factor for the development of SVAP, and patients with a short duration of hospitalization before intensive care unit admission have the highest incidence of ventilator-associated pneumonia caused by MSSA.