Longitudinal development of initial, chronic and mucoid Pseudomonas aeruginosa infection in young children with cystic fibrosis

Abstract

<div class="section"> <a class="named-anchor" id="S1"> <!-- named anchor --> </a> <h5 class="section-title" id="d3281404e185">Background</h5> <p id="P1">While the emergence of chronic and mucoid <i>Pseudomonas aeruginosa</i> ( <i>Pa</i>) infection are both associated with poorer outcomes among CF patients, their relationship is poorly understood. We examined the longitudinal relationship of incident, chronic and mucoid <i>Pa</i> in a contemporary, young CF cohort in the current era of <i>Pa</i> eradication therapy. </p> </div><div class="section"> <a class="named-anchor" id="S2"> <!-- named anchor --> </a> <h5 class="section-title" id="d3281404e202">Methods</h5> <p id="P2">This retrospective cohort was comprised of patients in the U.S. CF Foundation Patient Registry born 2006–2015, diagnosed before age 2, and with at least 3 respiratory cultures annually. Incidence and age-specific prevalence of <i>Pa</i> infection stages (initial and chronic [≥ 3 <i>Pa</i>+ cultures in prior year]) and of mucoid <i>Pa</i> were summarized. Transition times and the interaction between <i>Pa</i> stage and acquisition of mucoid <i>Pa</i> were examined via Cox models. </p> </div><div class="section"> <a class="named-anchor" id="S3"> <!-- named anchor --> </a> <h5 class="section-title" id="d3281404e222">Results</h5> <p id="P3">Among the 5,592 CF patients in the cohort followed to a mean age of 5.5 years, 64% (n=3,580) acquired <i>Pa</i>. Of those, 13% (n=455) developed chronic <i>Pa</i> and 17% (n=594) cultured mucoid <i>Pa</i>. Among those with mucoid <i>Pa</i>, 36% (211/594) had it on their first recorded <i>Pa</i>+ culture, while mucoid <i>Pa</i> emerged at or after entering the chronic stage in 12% (73/594). Mucoidy was associated with significantly increased risk of transition to chronic <i>Pa</i> infection (HR=2.59, 95% CI 2.11, 3.19). </p> </div><div class="section"> <a class="named-anchor" id="S4"> <!-- named anchor --> </a> <h5 class="section-title" id="d3281404e249">Conclusions</h5> <p id="P4">Two-thirds of early-diagnosed young children with CF acquired <i>Pa</i> during a median 5.6 years of follow up, among whom 13% developed chronic <i>Pa</i> and 17% acquired mucoid <i>Pa</i>. Contrary to our hypothesis, 87% of young children who developed mucoid <i>Pa</i> did so before becoming chronically infected. </p> </div>