Community-acquired methicillin-resistant Staphylococcus aureus pneumonia: A clinical audit

Background and objective: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains are primarily associated with skin and soft tissue infections; however, they are increasingly causing more invasive infections including severe community-acquired pneumonia. The objective of this study was to describe the clinico-pathological characteristics of community-acquired MRSA pneumonia. Methods: A retrospective analysis of case records from January 2002 to August 2008 was performed on patients admitted with community-acquired MRSA pneumonia to two large teaching hospitals. Results: Sixteen patients with community-acquired MRSA pneumonia were identified. Their age ranged from 11 months to 86 years (median age; 30 years). Duration of symptoms before hospital presentation ranged from one to 21 days. Most patients had productive cough, fever and dyspnoea. The most common radiological presentation included multilobar consolidation (8/16), necrotizing consolidation (7/16) and empyema (5/16). Seven patients required intensive care support; four required ionotropic support and five required mechanical ventilation for a mean duration of 53 h and 6.6 days, respectively. Six patients underwent surgery (VATS or open thoracotomy). There was a mean delay of approximately 69 h (range; 18 h to 11 days) after presentation before appropriate MRSA antimicrobial treatment was initiated. Three patients died of complications from pneumonia, all within 72 h of presentation. Among survivors, the average length of hospital stay was 23.8 days (range; 10-49 days). Majority of survivors were left with mild residual radiological changes. Conclusions: Community-acquired MRSA pneumonia is increasing and should be suspected in patients with severe community-acquired pneumonia. There was a delay in initiation of appropriate antimicrobial treatment that could have lead to increased morbidity. We describe the clinico-pathological characteristics of community-acquired methicillin-resistant Staphylococcus aureus pneumonia and report the emergence of community-associated methicillin-resistant S. aureus in Australia as a cause of community-acquired pneumonia resulting in severe morbidity and mortality in otherwise healthy persons