Eradication of persistent methicillin-resistant Staphylococcus aureus infection in cystic fibrosis

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in individuals with cystic fibrosis (CF) has increased significantly. While studies demonstrate that persistent MRSA infection in CF is associated with poor clinical outcomes, there are no randomized controlled studies informing management.

The Persistent MRSA Eradication Protocol was a double-blind, randomized, placebo-controlled study investigating a comprehensive 28-day treatment regimen with or without inhaled vancomycin for eradication of MRSA. Eligible participants had CF and documented persistent MRSA infection. All participants received oral antibiotics, topical decontamination, and environmental cleaning and were randomized to receive inhaled vancomycin or inhaled placebo. The primary outcome was the difference in MRSA eradication rates one month after completion of the treatment protocol.

29 participants were randomized. Four subjects in the inhaled vancomycin group required withdrawal from the study for bronchospasm before outcome data were collected and were excluded from analysis. There was no difference in the primary outcome: 2/10 (20%) of subjects in the intervention group and 3/15 (20%) in the placebo group had a MRSA negative sputum culture one month after treatment. There were no statistically significant differences in the rates of MRSA eradication at the end of treatment or three months after treatment completion.

This study suggests that persistent MRSA infection is difficult to eradicate, even with multimodal antibiotics. The use of a single course of inhaled vancomycin may not lead to higher rates of MRSA eradication in individuals with CF and may be associated with bronchospasm. FUND: This trial was financially supported by the Cystic Fibrosis Foundation.