Association between Staphylococcus aureus alone or combined with Pseudomonas aeruginosa and the clinical condition of patients with cystic fibrosis

J Cyst Fibros. 2013 Sep;12(5):497-503. doi: 10.1016/j.jcf.2012.12.003. Epub 2013 Jan 3.


Background: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients has increased and MRSA seems to be associated with a poorer prognosis. The aim of this study was to assess the prevalence and clinical consequences of MRSA and methicillin-susceptible Staphylococcus aureus (MSSA), associated or not associated with Pseudomonas aeruginosa (PA).

Methods: In a retrospective study on 419 sputum producer patients (293 adults and 126 children >7 years of age), we recorded patient characteristics, lung function, nutritional status, i.v. antibiotics and hospitalisations, the presence of SA and/or PA and FEV1 decline over 2 years.

Results: SA was found in 72% of the patients: MSSA in 68.2% of children and 48.8% of adults; MRSA in 17.5% of children and 17.8% of adults. Sixty percent of MRSA patients and 60.4% of MSSA patients also harboured PA. The rate of deterioration of clinical status of the various groups, as assessed from respiratory function, i.v. antibiotic courses and hospitalisations, increased in the order: no SA/no PA, MSSA alone, MRSA alone, MSSA/PA, MRSA/PA, and PA alone. Nutritional status did not differ between groups. Results were roughly similar for children and adults. The yearly FEV1 decline was significantly higher only for MRSA/PA patients (p=0.03) compared to no SA/no PA patients.

Conclusion: Clinical condition of CF patients with MSSA only or MRSA only appeared similar, whereas MRSA/PA patients had more severe respiratory function than MSSA/PA patients. In CF patients, MRSA might be more deleterious than MSSA only when associated with PA.

Keywords: Cystic fibrosis; Lung function; MRSA; Pseudomonas aeruginosa; Staphylococcus aureus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Cohort Studies
  • Cystic Fibrosis / complications*
  • Cystic Fibrosis / microbiology*
  • Female
  • Humans
  • Male
  • Methicillin-Resistant Staphylococcus aureus*
  • Middle Aged
  • Prevalence
  • Pseudomonas Infections / complications*
  • Pseudomonas Infections / epidemiology
  • Pseudomonas aeruginosa*
  • Retrospective Studies
  • Staphylococcal Infections / complications*
  • Staphylococcal Infections / epidemiology
  • Young Adult