title: Meticillin-resistant Staphylococcus aureus and meticillin-susceptible S. aureus pneumonia: comparison of clinical and thin-section CT findings.
abstract: OBJECTIVE
  The purpose of this study was to compare the clinical and thin-section CT findings in patients with meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-susceptible S. aureus (MSSA).
  
  
  METHODS
  We retrospectively identified 201 patients with acute MRSA pneumonia and 164 patients with acute MSSA pneumonia who had undergone chest thin-section CT examinations between January 2004 and March 2009. Patients with concurrent infectious disease were excluded from our study. Consequently, our study group comprised 68 patients with MRSA pneumonia (37 male, 31 female) and 83 patients with MSSA pneumonia (32 male, 51 female). Clinical findings in the patients were assessed. Parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed.
  
  
  RESULTS
  Underlying diseases such as cardiovascular were significantly more frequent in the patients with MRSA pneumonia than in those with MSSA pneumonia. CT findings of centrilobular nodules, centrilobular nodules with a tree-in-bud pattern, and bronchial wall thickening were significantly more frequent in the patients with MSSA pneumonia than those with MRSA pneumonia (p = 0.038, p = 0.007 and p = 0.039, respectively). In the group with MRSA, parenchymal abnormalities were observed to be mainly peripherally distributed and the frequency was significantly higher than in the MSSA group (p = 0.028). Pleural effusion was significantly more frequent in the patients with MRSA pneumonia than those with MSSA pneumonia (p = 0.002).
  
  
  CONCLUSIONS
  Findings from the evaluation of thin-section CT manifestations of pneumonia may be useful to distinguish between patients with acute MRSA pneumonia and those with MSSA pneumonia.
authors.affiliation: Department of Radiology, Oita University Faculity of Medicine, Oita, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Morikawa
authors.forename: F
authors.initials: F
authors.lastname: Okada
authors.forename: Y
authors.initials: Y
authors.lastname: Ando
authors.forename: R
authors.initials: R
authors.lastname: Ishii
authors.forename: S
authors.initials: S
authors.lastname: Matsushita
authors.forename: A
authors.initials: A
authors.lastname: Ono
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.forename: S
authors.initials: S
authors.lastname: Yamashita
authors.forename: K
authors.initials: K
authors.lastname: Kawahara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008712:Methicillin / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D012189:Retrospective Studies; D013211:Staphylococcus aureus / Q000187:drug effects; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D008712:Methicillin