General information on antibiotic therapy for cystic fibrosis

Antibiotic therapy in CF can be used for eradication of infection, to suppress chronic established infections, and to manage exacerbations.

Antibiotic therapy for lung disease in CF varies between different specialist CF centres, and is based on general principles and local experience because of a lack of evidence-based recommendations.

The dose of antibiotic therapy, including the dosing interval and duration, are different from those used for infections caused by the same pathogens in patients without CF. For all antibiotic therapy, the drug and dose must be directed by the patient’s CF management plan or decided in consultation with the specialist CF centre.

The choice of drug may be determined by the infecting organism and its antibiotic susceptibility. Patients are often given the antibiotic used to successfully treat the pathogen cultured in the previous sputum sample while waiting for results of susceptibility testing of a current sputum sample. If the patient is clinically responding to the initial antibiotic, treatment is continued, even if the results of the current sputum sample suggest that the infection is not susceptible.

In young patients with CF, the pathogen may be unknown because many patients are not able to produce a sputum sample until the age of 6 to 7 years. Some centres in Australia use bronchoalveolar lavage (BAL) to obtain bronchial secretions in young children. The use of throat swab cultures in infants with CF is not ideal.

Most specialist CF centres obtain respiratory cultures four times a year, as well as during respiratory exacerbations. Antibiotic therapy for the eradication treatment is determined by the specialist CF centre.