title: Community-acquired methicillin-resistant Staphylococcus aureus pneumonia: radiographic and computed tomography findings.
abstract: OBJECTIVE
  The aim of our study was to review the radiologic findings of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) pneumonia.
  
  
  METHODS
  The hospital infection control computer database was used to identify patients who had a CA-MRSA infection with organisms isolated from blood, bronchoalveolar lavage fluid, or pleural fluid samples. Criteria for CA-MRSA pneumonia were consolidation seen on chest radiography or computed tomography (CT), growth of MRSA from sputum and/or sterile pulmonary site, clinical complaints of cough and/or shortness of breath. Chest radiographs and CT scans for 9 patients (5 men, mean age 45 y, range 35 to 71 y) were retrospectively reviewed by 2 chest radiologists.
  
  
  RESULTS
  The most common chest radiographic finding was consolidation, which was bilateral in 7 patients and unilateral in 2 patients. The consolidation was patchy and nonsegmental in 5 and segmental in 4 patients. Two patients had cavitation evident on the chest radiograph. The most common CT scan findings were bilateral (n=8), often symmetric (n=5) consolidation, bilateral septal lines (n=7), and multiple nodules (n=5). Cavitation was present in 5 patients, either in regions of consolidation (n=5) or in large nodules (n=3). Five patients with CA-MRSA pneumonia had rapid clinical deterioration requiring ventilatory support. Two patients died.
  
  
  CONCLUSIONS
  CA-MRSA pneumonia is characterized by extensive bilateral consolidation and frequent cavitation and is commonly associated with rapid progression and clinical deterioration. CT is superior to radiography in demonstrating the presence of cavitation.
authors.affiliation: Department of Radiology, Vancouver General Hospital and The University of British Columbia, Vancouver, BC. enguyen2@stanford.edu
authors.forename: Elsie T
authors.initials: ET
authors.lastname: Nguyen
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Kanne
authors.forename: Linda M N
authors.initials: LM
authors.lastname: Hoang
authors.forename: Steven
authors.initials: S
authors.lastname: Reynolds
authors.forename: Vinay
authors.initials: V
authors.lastname: Dhingra
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bryce
authors.forename: Nestor L
authors.initials: NL
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000382:microbiology; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000382:microbiology; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000175:diagnosis* / Q000382:microbiology; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D014057:Tomography, X-Ray Computed / Q000379:methods*