Antibiotic Treatment and Age Are Associated With Carriage Profiles During Persistence in the Airways of Cystic Fibrosis Patients.

Background: is one of the most isolated pathogens from the airways of cystic fibrosis (CF) patients. There is a lack of information about the clonal nature of cultured from CF patients and their impact on disease. We hypothesized that patients would differ in their clinical status depending on clonal carriage profiles during persistence.

Methods: During a 21-months prospective observational multicenter study (Junge et al., 2016), 3893 isolates (nose, oropharynx, and sputa) were cultured from 183 CF patients (16 German centers, 1 Austrian center) and subjected to -sequence typing to assess clonality. Data were associated to lung function, age, gender, and antibiotic treatment by multivariate regression analysis.

Results: Two hundred and sixty-five different -types were determined with eight prevalent -types (isolated from more than 10 patients): t084, t091, t008, t015, t002 t012, t364, and t056. We observed different carriage profiles of -types during the study period: patients being positive with a prevalent -type, only one, a dominant or related -type/s. Patients with more antibiotic cycles were more likely to be positive for only one -type ( = 0.005), while older patients were more likely to have related ( = 0.006), or dominant -types ( = 0.026). Two percent of isolates were identified as methicillin-resistant (MRSA) and evidence of transmission of clones within centers was low.

Conclusion: There was a significant association of antibiotic therapy and age on carriage profiles in CF patients indicating that antibiotic therapy prevents acquisition of new clones, while during aging of patients with persisting , dominant clones were selected and mutations in the repeat region accumulated.