Ethnic differences in staphylococcus aureus acquisition in cystic fibrosis

Hispanic people with CF (pwCF) have increased morbidity than non-Hispanic White pwCF, including increased risk of Pseudomonas aeruginosa. We aimed to determine if Staphylococcus aureus (S. aureus) acquisition varies between Hispanic and non-Hispanic White pwCF.

This longitudinal cohort study of pwCF ages 0-25 years in the CF Foundation Patient Registry compared acquisition of methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), persistent MRSA between Hispanic and non-Hispanic White pwCF. Risk of acquisition was assessed by Kaplan-Meier survival curves and its association with ethnicity was evaluated using Cox regressions. Adjusted associations were evaluated using multivariate Cox models adjusting for sex, age of entry into CFFPR, CFTR variant severity, pancreatic insufficiency, CF-related diabetes, maternal education, insurance status.

Of 10,640 pwCF, 7.5% were Hispanic and 92.5% were non-Hispanic White. Hispanic pwCF had a 19% higher risk of acquiring MSSA (HR 1.19, 95% CI 1.10-1.28, p<0.001) and 13% higher risk of acquiring MRSA (HR 1.13, 95% CI 1.02-1.26, p = 0.02) than non-Hispanic White pwCF. The difference in persistent MRSA between ethnicities did not reach statistical significance. After adjusting for confounding variables, only the risk of MSSA was significantly associated with ethnicity. Compared to non-Hispanic White pwCF, Hispanic pwCF acquired MSSA and MRSA at younger median ages (4.9 vs. 3.8 years (p<0.001), 22.4 vs. 20.8 years (p = 0.02).

Hispanic pwCF <25 years of age have an increased risk of acquiring MSSA and acquired MSSA and MRSA at an earlier age. Differences in S. aureus acquisition may contribute to increased morbidity in Hispanic pwCF.