Late viral or bacterial respiratory infections in lung transplanted patients: impact on respiratory function

Background Respiratory infections are a major threat for lung recipients. We aimed to compare with a monocentric study the impact of late viral and bacterial respiratory infections on the graft function. Methods Patients, who survived 6 months or more following lung transplantation that took place between 2009 and 2014, were classified into three groups: a viral infection group (VIG) (without any respiratory bacteria), a bacterial infection group (BIG) (with or without any respiratory viruses), and a control group (CG) (no documented infection). Chronic lung allograft dysfunction (CLAD) and acute rejection were analysed 6 months after the inclusion in the study. Results Among 99 included lung recipients, 57 (58%) had at least one positive virological respiratory sample during the study period. Patients were classified as follows: 38 in the VIG, 25 in the BIG (among which 19 co-infections with a virus) and 36 in the CG. The BIG presented a higher initial deterioration in lung function ( p = 0.05) than the VIG. But 6 months after the infection, only the VIG presented a median decrease of forced expiratory volume in 1 s; − 35 mL (IQR; − 340; + 80) in the VIG, + 140 mL (+ 60;+ 330) in the BIG and + 10 (− 84;+ 160) in the CG, p < 0.01. Acute rejection was more frequent in the VIG ( n = 12 (32%)), than the BIG ( n = 6 (24%)) and CG ( n = 3 (8%)), p < 0.05, despite presenting no more CLAD ( p = 0.21). Conclusions Despite a less severe initial presentation, single viral respiratory infections seem to lead to a greater deterioration in lung function, and to more acute rejection, than bacterial infections.