Burkholderia contaminans in cystic fibrosis over a 15-year period in a reference center in Argentina

LAURA BELTINA LEON; VIRGINIA D´ALESSANDRO; MARIANA LEGIZAMÓN; MARISA BETTIOL; MACARENA ALGAÑARAS; DANIELA CASCO; CAROLINA VITA; CLAUDIA PRIETO; CECILIA BEATRIZ FÍGOLI; NATALIA IRYGOYEN; CECILIA VESCINA; OSVALDO YANTORNO; FERNANDO RENTERÍA; ALEJANDRA BOSCH

Liverpool

Congreso; 42nd European Cystic Fibrosis Conference; 2019

European Cystic Fibrosis Society

Objectives: Airways colonization by Burkholderia contaminans is generally associated with a rapid lung function decline and increased mortality in patients with CF. The aim of this study is to contribute to the understanding of the relevant aspects of chronic respiratory infections mediated by B. contaminans based on the analysis of microbial characteristics and patients? clinical outcome. Methods: This study was conducted with 16 patients with CF colonized by B. contaminans being attended at the CF reference center, Hospital ?Sor María Ludovica?, La Plata, Argentina since 2004. A total of 31 isolates recovered from respiratory sample were analyzed. They were identified by MLST and characterized by colony morphology, mucoidicity, quorum sensing, and other virulence factors. Children´s clinical status was evaluated by the nutritional parameter zBMI, and the number of pulmonary exacerbations during the infection. Results: A considerable low diversity among B. contaminans sequence types (STs) was encountered (872, 102 and 432 STs). Although long-term respiratory infections by all STs lead to a significant decline in patients´ lung function, colonization by ST 102, results in an earlier lung deterioration. Interestingly, among the 3 patients with the worse clinical outcome, 2 were colonized by bacteria that converted to brownpigmented-small-colony variant (SCV), while isolates recovered from the third patient, switched to non-mucoid phenotype during the infection. None of the 4 patients in the studied population who died developed ?cepacia syndrome? but, interestingly isolates recovered from 3 of them also switched to the non-mucoid phenotype in last years of infection. Conclusion: We here report for the first time that B. contaminans adaptation that results, either in a switch to non-mucoid phenotype, the emergence of SCV, and/or the acquisition of pigmentation along the chronic infection, leads to a rapid lung decline, independently of the species linage.