Use of Antibiotic Prophylaxis in Young Children With Cystic Fibrosis

bacterial culture in petri dish
bacterial culture in petri dish
In children with cystic fibrosis, risk for first detection of S aureus and P aeruginosa was greater in those who had received antibiotic prophylaxis.

Antibiotic prophylaxis decreased risk for first detection of Staphylococcus aureus and Pseudomonas aeruginosa in young children with cystic fibrosis (CF), according to a study published in the Annals of the American Thoracic Society, but flucloxacillin prophylaxis increased risk for first P aeruginosa detection compared with no prophylaxis.

The issue of antibiotic prophylaxis in CF is controversial. Although it is standard care in the United Kingdom, it is not in the United States. Matthew N. Hurley, MB BCh, MRCPCH, PhD, from the University of Nottingham, United Kingdom, and colleagues compared UK and US cohorts to determine whether antistaphylococcal prophylaxis decreased risk for S aureus acquisition without increasing risk for P aeruginosa acquisition.

The longitudinal observational study followed 1074 British children and 3677 American children with cystic fibrosis recruited from birth for the first 4 years of life, using UK CF Trust and US CF Foundation registries between 2000 and 2009. A UK-based analysis also compared children receiving flucloxacillin with children who received no prophylaxis.

The risk for first detection of S aureus and P aeruginosa was greater in the United States than the United Kingdom (hazard ratio [HR], 5.79 [95% CI, 4.85-6.90; P <.001] and HR, 1.92 [95% CI, 1.65-2.24; P <.001], respectively). The UK analysis compared 278 children who received flucloxacillin with 306 who received no prophylaxis. In contrast to the other results, the authors did not observe a reduction in risk for S aureus (HR, 1.22; 95% CI, 0.74-2.0; P =.43), but flucloxacillin was associated with increased risk for P aeruginosa (HR, 2.53; 95% CI, 1.71-3.74; P <.001).

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The authors noted that an important limitation of the study is its reliance on oropharyngeal and cough swabs, which have relatively low sensitivity and specificity for lower airway infection. However, the large numbers of children in the database is a significant strength.

Nonetheless, the authors recommend interpreting the data with caution. Although S aureus infection had devastating effects on young children with CF in the 1960s and 1970s, improved management and survival of children with CF currently suggest that the balance of risks and benefits of staphylococcal prophylaxis has changed and that the “tenet of first do no harm” should be applied.


Hurley MN, Fogarty A, McKeever TM, Goss CH, Rosenfeld M, Smyth AR. Early respiratory bacterial detection and anti-staphylococcal antibiotic prophylaxis in young children with cystic fibrosis [published online October 16, 2017]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201705-376OC