Presence of methicillin resistant Staphylococcus aureus in respiratory cultures from cystic fibrosis patients is associated with lower lung function

Pediatr Pulmonol. 2007 Jun;42(6):513-8. doi: 10.1002/ppul.20604.


The prevalence of methicillin resistant Staphylococcus aureus (MRSA) infections is increasing in both the general population and cystic fibrosis (CF) patients. We hypothesized that MRSA infection of the conductive airways as seen in CF would be associated with more severe disease than that seen with methicillin sensitive S. aureus (MSSA). To test this hypothesis, we used data from the Epidemiologic Study of Cystic Fibrosis (ESCF), a large observational study of CF patients in North America, to compare CF patients with MRSA in their respiratory tract cultures to those with MSSA. During a 1-year time period from January 1, 2001 to December 31, 2001, data from 20,451 patients were collected by the ESCF, and 1,834 (7.5%) patients had respiratory tract cultures that were positive for S. aureus only. Compared to patients with MSSA only, patients with MRSA only had significantly more airflow obstruction, as measured by forced expiratory volume in 1 sec (FEV1). The mean FEV1 for patients 6-17 years old with MRSA was 80.7% predicted compared to 89.4% in the MSSA group (P<0.001). The likelihood of hospitalization and treatment with oral, inhaled, and intravenous antibiotics were all significantly increased in patients with MRSA compared to those with MSSA. Similar results were seen in patients >or=18 years old. The results of our study highlight the growing clinical impact of MRSA infections in CF patients.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / therapeutic use
  • Cells, Cultured
  • Child
  • Cystic Fibrosis / microbiology
  • Cystic Fibrosis / pathology
  • Cystic Fibrosis / physiopathology*
  • Forced Expiratory Volume / physiology
  • Humans
  • Methicillin / therapeutic use
  • Methicillin Resistance*
  • Prevalence
  • Respiratory Physiological Phenomena
  • Respiratory System / microbiology*
  • Respiratory System / pathology*
  • Respiratory System / physiopathology
  • Respiratory Tract Infections / drug therapy
  • Respiratory Tract Infections / microbiology
  • Respiratory Tract Infections / physiopathology*
  • Retrospective Studies
  • Severity of Illness Index
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / physiopathology*
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / pathogenicity*
  • Staphylococcus aureus / physiology


  • Anti-Bacterial Agents
  • Methicillin