Prophylactic antibiotics for cystic fibrosis.
BACKGROUND
Cystic fibrosis blocks the airways with mucus and causes frequent respiratory infections. This leads to inflammation and lung disease, which frequently causes death from breathing failure. People with cystic fibrosis are sometimes given antibiotics regularly, in an attempt to prevent infections. However, antibiotics also have adverse effects, and longterm use might lead to the development of infections that can no longer be cleared by antibiotics. The review found some evidence from trials that preventive antibiotics for babies continued to two years may have some benefits. However, there is no evidence of the effects on adults or of longterm use.


OBJECTIVE
We aimed to compare continuous oral antibiotic prophylaxis with no prophylaxis (short courses of oral antibiotics given as clinically indicated) in patients with cystic fibrosis. This review considers both the effectiveness of prophylaxis (bacteria isolated from the respiratory tract, requirement for additional antibiotic treatment, lung function, survival) and the adverse effects.


METHODS
The Cochrane Cystic Fibrosis and Genetic Disorders Group clinical trials register was used. This comprises references identified from a comprehensive search of electronic databases, as well as hand searching relevant journals and conference abstracts. Companies manufacturing anti-staphylococcal antibiotics were also approached for unpublished data. Date of the most recent search of the Group's specialised register: February 2001.


METHODS
All randomised or pseudo-randomised trials where continuous oral prophylactic antibiotics, given for a period of at least one year, were compared to intermittent antibiotic therapy given "as required." Cystic fibrosis patients of any disease severity were considered.


METHODS
Trials were assessed for eligibility, methodological quality and data extraction by the reviewers. The following outcomes were assessed: lung function; nutrition (weight standard deviation score); survival; requirement for additional antibiotic treatment; isolates of pathogens from the respiratory tract; occurrence of adverse reactions to prophylactic antibiotics.


RESULTS
Three studies, totaling 177 patients aged 0-7 years on enrollment, were suitable for inclusion in the review. A reduced prevalence of Staphylococcus aureus in the respiratory secretions was seen in children receiving anti-staphylococcal antibiotic prophylaxis, although no effect was seen on other common pathogens. One eligible study showed a shorter duration of hospital admissions in the second year of life, in patients receiving prophylaxis. No effect on infant lung function has been shown after one year of prophylactic treatment. Data are not available on adverse effects of the interventions. There was a trend towards a lower cumulative isolation rate of Pseudomonas aeruginosa in the prophylaxis group, after three years. However, as the duration of the studies reviewed has been of three years or less, conclusions cannot be drawn about the long term effects of prophylaxis on acquisition of P. aeruginosa and survival.


CONCLUSIONS
Anti-staphylococcal antibiotic prophylaxis may be of benefit when commenced early in infancy and continued up to three years of age. There is insufficient evidence from this review to say whether use in older children, or adults, or for periods of over three years is beneficial.
Smyth
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Department of Paediatrics, Nottingham City Hospital, Hucknall Road, Nottingham, UK, NG5 1PB. DrAlanSmyth@compuserve.com
Walters
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D000328:Adult; D019072:Antibiotic Prophylaxis; D002648:Child; D003550:Cystic Fibrosis / Q000382:microbiology*; D006801:Humans; D007223:Infant; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000517:prevention & control*; D013203:Staphylococcal Infections / Q000517:prevention & control