Use of elexacaftor/tezacaftor/ivacaftor leads to changes in detection frequencies of Staphylococcus aureus and Pseudomonas aeruginosa dependent on age and lung function in people with CF

Objectives

The impressive improvements of CFTR function by elexacaftor/tezacaftor/ivacaftor (ETI) result in changes in the detection frequencies of Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA). We assessed determinants of the response to ETI with regards to SA and PA detection frequencies as documented in the German CF Registry for people with CF (pwCF) ≥12 years.

Methods

We evaluated changes in the detection frequencies of SA and PA for 21 months before and after initiation of ETI and used different statistical tests to identify determinants of detection changes.

Results

We included data from 1,092 pwCF with results from culture-dependent diagnostics for SA and PA detection from 7,944 microbiological samples prior and 6.845 microbiological samples after initiation of ETI. Detections of SA decreased from 54.3% to 44.3% and 40.2% and those of PA from 39.9% to 31.9% and 22.6% 3 and 21 months after initiation of therapy, respectively (all p<0.001). Reduction of SA and PA were observed in throat swabs and sputa, associated significantly with age, prior lung function and were dependent on pre-ETI colonization status.

Conclusions

The different patterns of reductions of SA and PA suggest that pathogen-specific biological processes govern the responsiveness of microbiological colonization towards ETI in pwCF.