CFTR and cystic fibrosis: To determine whether the encouraging efficacy of APR that we have previously observed in a hollow fibre infection model30 and an M. abscessus mouse infection model11 holds up against another bacterial strain and in a CF surrogate model, we infected CFTR−/− mice by intratracheal inoculation with 0.5–1 × 106 CFU of M. abscessus subsp.