Background: We describe Pseudomonas aeruginosa acquisitions in children with cystic fibrosis (CF) aged ≤. 5-years, eradication treatment efficacy, and genotypic relationships between upper and lower airway isolates and strains from non-CF sources. Methods: Of 168 CF children aged ≤. 5-years in a bronchoalveolar lavage (BAL)-directed therapy trial, 155 had detailed microbiological results. Overall, 201/271 (74%) P. aeruginosa isolates from BAL and oropharyngeal cultures were available for genotyping, including those collected before and after eradication therapy. Results: Eighty-two (53%) subjects acquired P. aeruginosa, of which most were unique strains. Initial eradication success rate was 90%, but 36 (44%) reacquired P. aeruginosa, with genotypic substitutions more common in BAL (12/14) than oropharyngeal (3/11) cultures. Moreover, oropharyngeal cultures did not predict BAL genotypes reliably. Conclusions: CF children acquire environmental P. aeruginosa strains frequently. However, discordance between BAL and oropharyngeal strains raises questions over upper airway reservoirs and how to best determine eradication in non-expectorating children.

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Journal of Cystic Fibrosis
Erasmus MC: University Medical Center Rotterdam

Kidd, T.J, Ramsay, K.A, Vidmar, S, Carlin, J.B, Bell, S.C, Wainwright, C.E, … Bard, M.P.L. (2015). Pseudomonas aeruginosa genotypes acquired by children with cystic fibrosis by age 5-years. Journal of Cystic Fibrosis, 14(3), 361–369. doi:10.1016/j.jcf.2014.12.007