Microbiological outcomes associated with Burkholderia species in people with cystic fibrosis receiving CFTR modulator therapy.

INTRODUCTION

Burkholderia cepacia complex (BCC) comprises 25 species known to cause disease primarily in people with cystic fibrosis (pwCF). Isolation of BCC has major implications for infection control, eradication strategies, morbidity, and lung transplant eligibility. Although not considered part of the BCC, other Burkholderia species are known to cause respiratory disease in pwCF, namely Burkholderia gladioli and Burkholderia pseudomallei. The introduction of CFTR modulator therapy has improved pulmonary outcomes in pwCF, yet little is known about their impact on Burkholderia species acquisition, clearance, or long-term microbiological or clinical outcomes.

METHOD: We reviewed the outcomes of pwCF infected with Burkholderia species (including BCC, B. gladioli, or B. pseudomallei) receiving care in a large CF centre over the past 15 years, spanning the introduction of CFTR modulator therapy.

RESULTS

Forty-four pwCF cultured one of these organisms between 2010 and 2025. Ten had only a single isolation with 28 (63.6%) deemed to have chronic infection and 6 (13.6%) exhibiting transient infection defined by having only two positive cultures. Notably, no new Burkholderia species acquisitions occurred after commencement of elexacaftor/tezacaftor/ivacaftor (ETI). The longitudinal incidence rates of chronic infection with Burkholderia species showed a reducing trend from 2017-2025 with rates of spontaneous clearance following ETI appearing similar to background clearance rates prior to modulator therapy.

CONCLUSION

These findings contribute to the evolving understanding of Burkholderia species in the modulator era. While ETI does not eliminate the risk of chronic infection, it may reduce acquisition and support clearance in a subset of pwCF.