Colistin-based treatment of multidrug-resistant gram-negative bacterial pulmonary infections after lung transplantation

Background: Lung transplantation (LT) is a viable option for a select group of patients with end-stage lung disease. However, infections are a major complication after LT, accounting for significant morbidity and mortality. Several germs may be responsible; multidrug-resistant Gram-negative (MDR-GN) bacteria are emerging. Colistin is widely used in the treatment of these infections and is administered by inhalation and/or parenterally. At our institution, in patients with tracheostomy, colistin is administered by direct instillation in the airway during bronchoscopy. We reviewed a series of patients who underwent LT complicated by postoperative MDR-GN bacterial pulmonary infection. Methods: From January 2015 to May 2017, 26 lung transplants were performed. In the postoperative course, 14 (54%) developed MDR-GN bacterial infection; respiratory specimen culture, blood tests, and chest X-ray were considered. Colistin was the only antibiotic usable. Thirteen patients received intravenous (IV) colistin; in the subgroup of patients with tracheostomy, colistin was instilled directly in the airway, and 6 patients received inhaled colistin. Results: Seven patients needed tracheostomy. Pseudomonas aeruginosa was the predominant infection (86%), with Acinetobacter baumanii seen in 2 cases (14%). An early clinical-laboratory response was observed in 9 patients (64%). White blood cell count and C-reactive protein values improved (P =.02 and P =.001, respectively). A significant reduction in bacterial load was observed on microbiologic bronchoalveolar lavage specimens. Conclusion: Colistin instilled directly in the airway did not show side effects. The combination of IV and inhaled/instilled colistin could be a useful treatment option for MDR-GN infections after LT.