Significant differences from bronchoalveolar lavage (BAL) surveillance conducted among preschool children with cystic fibrosis (CF), according to their country of residence, have been reported in an international comparison published in the American Journal of Respiratory and Critical Care Medicine.1
In the most recent study, data were collected from 335 BAL samples obtained from 110 children at 3 specialist CF centers in Ireland.
In these samples, which were collected between 2010 and 2018, investigators observed an encouraging reduction in the prevalence of Pseudomonas aeruginosa infections in BAL among the children over time. They did note, however, 2 distinct differences between their data and those published in an Australian study by Breuer and colleagues.2 First, although the prevalence of infection caused by P aeruginosa in the current study did not differ significantly from that reported in the Australian study, the prevalence of both Staphylococcus aureus and Haemophilus influenzae was significantly higher, and the prevalence of P aeruginosa significantly lower, in the Irish cohort study.
Further, obvious differences were seen in the prevalence of S aureus and H influenzae that decreased with age, along with an increased difference in the rates of infection with Aspergillus species, which become significant in the older patient cohort only (5-6 years; P <.001). Because of the apparently homogeneous approach to the treatment of young children with CF, along with the processing of airway specimens in the clinical laboratories of specialist centers in the developed world, these data were somewhat unexpected.
Similar to their Australian counterparts, the Irish researchers noted that they also tackle airway clearance and the treatment of intercurrent infections in their young cohort of patients in an aggressive fashion. Furthermore, they routinely treat patients younger than 2 years with antistaphylococcal prophylaxis, typically flucloxacillin, as opposed to co-amoxiclav. They reserve treatment with co-amoxiclav for low-grade exacerbations and use azithromycin prophylaxis in certain children in this age group as well.
The authors of the Irish study concluded that the differences observed among the populations of preschoolers from Ireland and Australia could be attributed, in part, to cumulative antibiotic exposure, with more antibiotics being used overall in the Australian children than in the Irish children. An alternative possibility for the observed differences in the prevalence of airway pathogens is local environment. Additional research is warranted, with structured longitudinal clinical studies and international comparator analyses.
1. Hulme KM, Linnane B, McNally PG. Lower airway infection in preschool children with cystic fibrosis – an international comparison [published online November 26, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201910-2064LE
2. Breuer O, Schultz A, Turkovic L, et al. Changing prevalence of lower airway infections in young children with cystic fibrosis. Am J Respir Crit Care Med. 2019;200(5):590-599.