The impact of fluoroquinolone resistance of Gram-negative bacteria in respiratory secretions on the outcome of lung transplant (non-cystic fibrosis) recipients

Bacterial airway colonization is frequent among lung transplant recipients. These patients are often treated with antibiotics, which may lead to selection of resistant bacteria. The purpose of this study was to assess whether antibiotic treatment causes acquisition of quinolone-resistant Gram-negative bacteria (QR-GNB), and the effect of such colonization on mortality and on lung rejection. We retrospectively examined data from non-cystic fibrosis, non-bronchiectases lung transplant recipients for antibiotic treatment, GNB in respiratory secretions, bronchiolitis obliterans syndrome (BOS), and mortality. Of 126 patients included, 86 patients had QR-GNB, 22 had quinolone-sensitive bacteria (QS-GNB), and 17 had no growth. Median antibiotic exposure, defined as the fraction of days with antibiotic treatment, was 2.8% in patients without growth, 11.1% in patients with QS-GNB (p = 0.012), and 26% in patients with QR-GNB (p < 0.0001). Age-adjusted mortality hazard ratio was 9.2 (95% CI 1.272-78.9) for patients with QR-GNB compared with QS-GNB. Age-adjusted hazard ratios for BOS was 3.7 (95% CI 1.33-10.3) for QR-GNB compared with QS-GNB. We found a positive correlation between antibiotic treatment and emergence of QR-GNB. Airway colonization with QR-GNB was significantly associated with mortality and with BOS. Further research is needed to determine whether a change in antibiotic subscription policy is required.