Evaluation of Methicillin-Resistant Staphylococcus aureus Eradication in People With Cystic Fibrosis

People with cystic fibrosis (pwCF) have impaired bacterial mucociliary clearance, which can result in colonization with pathogens like Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) in the lower airway. Although guidelines for the eradication of P. aeruginosa in CF are well-established, MRSA eradication guidelines are lacking. This study aimed to determine the rates of MRSA eradication in pwCF based on a prescribed antibiotic regimen.

This retrospective chart review included pwCF with a first lifetime positive MRSA respiratory culture or first positive MRSA respiratory culture after at least 1 year of MRSA negativity (minimum of 4 negative respiratory cultures) obtained at Nationwide Children's Hospital between August 1, 2012, and February 28, 2022. Secondary outcomes assessed the impact of adding topical decontamination on MRSA eradication and the time to a subsequent MRSA-positive respiratory culture after completing the eradication regimen.

Sixty-two patients were included, and 16% achieved MRSA eradication. Intravenous vancomycin transitioned to oral trimethoprim-sulfamethoxazole achieved the highest eradication rate of 75% (p = 0.008). Antibiotics consisting of dual therapy with rifampin and topical decontamination had a higher rate of eradication (25%) compared with antibiotics alone, antibiotics with topical decontamination, or no antibiotics. Four patients had no subsequent MRSA-positive cultures, including 2 patients who did not receive antibiotics.

The transition from intravenous vancomycin to oral trimethoprim-sulfamethoxazole had the highest rate of MRSA eradication. Overall rates of MRSA eradication at 12 months in patients CF using antibiotics with or without topical decontamination are low.