Utilization of antibiotics for methicillin-resistant Staphylococcus aureus infection in cystic fibrosis

The purpose of this study was to characterize the utilization of antibiotics for chronic methicillin-resistant Staphylococcus aureus (MRSA) infection in cystic fibrosis (CF) patients with acute pulmonary exacerbations (PEx).

An anonymous national cross-sectional survey of CF Foundation accredited care programs was performed using an electronic survey tool.

Fifty-eight percent (152/261) CF Foundation accredited programs completed the survey. Ninety-eight percent (149/152) of respondents reported using antibiotics (oral or intravenous) against MRSA. Variability exists in the use of antibiotics amongst the programs and in the dosages utilized. For oral outpatient treatment, sulfamethoxazole/trimethoprim was the most commonly utilized antibiotic by both pediatric (109/287, 38%) and adult (99/295, 34%) respondents, of which, ten percent of reported to use it in combination with rifampin. For inpatient treatment, linezolid (both intravenous (IV) and oral) was most commonly utilized in both pediatric (IV 35/224, 16%; oral 41/224, 18%), and adult (IV 44/235, 19%; oral 38/235, 16%) respondents for inpatient treatment. IV vancomycin was the second most commonly utilized antibiotic by pediatric (70/224, 31%) and adult (71/235, 30%) respondents. Most respondents reported dose titration to achieve a vancomycin trough level of 15-20 mg/L (150/179, 84%). Topical or inhaled antibiotic utilization was reported to be an uncommon practice with approximately 70% of pediatric and adult respondents reporting to use them either rarely or never. The concomitant use of anti-MRSA and anti-pseudomonal antibiotics was common with 96% of pediatric and 99% of adult respondents answering in the affirmative.

We conclude that anti-MRSA antibiotics are utilized via various dosage regimens by a majority of CF Foundation accredited care programs for the treatment of chronic MRSA in PEx, and there is no consensus on the best treatment approach.