Adherence to Anti-Staphylococcal Prophylaxis in the First Two Years of Life and Microbiological Outcomes in the First Six Years of Life in Children With Cystic Fibrosis.

OBJECTIVE

To assess the relationship between adherence to anti-staphylococcal prophylaxis with amoxycillin-clavulanic acid in the first 2 years of life in children with cystic fibrosis (CF) and microbiological outcomes in the first 6 years of life.

METHODS

We conducted a retrospective cohort study of adherence to antistaphylococcal prophylaxis in children diagnosed with cystic fibrosis between 2000 and 2014 in Western Australia. Adherence (high defined as ≥ 90%, low defined as ≤ 70% days covered) was compared to microbial culture results from bronchoalveolar lavage collected during annual disease surveillance. Fisher's exact tests were used to examine the association between adherence and the presence of three major lung pathogens (S. aureus, P. aeruginosa, and Aspergillus species) across three age ranges (0-2 y.o., 3-4 y.o., and 5-6 y.o.).

RESULTS

124 patients were included in the analysis. Adherence rates were high at 93% (median, interquartile range 67.8%-99.0%). Over 6 years prevalence of S. aureus ranged from 4% to 12%, P. aeruginosa ranged from 2% to 10% and Aspergillus ranged from 4% to 20%. There were no statistically significant differences in culture positivity between high and low adherence groups during the study period. Specifically, increased adherence was not associated with significant differences in the culture rates of lung pathogens.

CONCLUSIONS

In children with CF, adherence to anti-staphylococcal prophylaxis in the first 2 years of life is not associated with a decrease in S. aureus in the lower airways, questioning the value of such prophylaxis.