Empirical therapy for suspected staphylococcal high-severity CAP in adults
Staphylococcus aureus is an uncommon cause of CAP in adults. It usually causes high-severity CAP or cavitary pneumoniaCilloniz, 2021. Staphylococcal pneumonia caused by methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) can occur as a primary infection, or following influenza. It can also occur as a metastatic complication of S. aureus bacteraemia or right-sided endocarditis, particularly in people with a history of injecting drugs.
Consider vancomycin for patients who have microbiological evidence suggestive of staphylococcal pneumonia (eg profuse gram-positive cocci resembling staphylococci identified on Gram stain of a respiratory tract sample1), or clinical features suggestive of staphylococcal pneumonia (eg cavitary pneumonia, pneumonia occurring after influenza, rapidly progressing pneumonia).
Vancomycin is the empirical antibiotic of choice because of increased prevalence of methicillin-resistant S. aureus (MRSA). Add to the empirical therapy regimen:
vancomycin 25 mg/kg (actual body weight) rounded up to nearest 125 mg, up to 3 g intravenously, as a loading dose. See Calculated vancomycin loading dosage in critically ill adults for calculated weight-based loading doses. Subsequent doses are dependent on weight and kidney function; see Intermittent vancomycin dosing in critically ill adults. vancomycin vancomycin vancomycin
If staphylococcal pneumonia is confirmed by investigations, see Staphylococcal pneumonia. If S. aureus is not identified, stop vancomycin and modify therapy based on the results of culture and susceptibility testing – see Directed therapy for pneumonia.