Seasonal changes of lower respiratory tract infections in lung transplant recipients during the first post-transplant year: The Hungarian experience.

Background: After lung transplantation (LuTX) a high level of immunosuppression is needed to prevent rejection of the graft. Together with earlier colonization by pathogens, immunosuppression makes recipients more susceptible to infections, especially during the first postoperative year. As seasonality of lower respiratory tract infections (LRTI) is well-known in chronic lung diseases, we assessed seasonal changes of pathogen spectrum and number of infections in the first postoperative year in LuTX recipients. Methods: LRTI were analyzed in 28 Hungarian adult LuTX patients. Incidence and spectrum of microorganism causing LRTI were evaluated according to post-transplant time and seasonal temperature and humidity changes. Results: A total of 69 cases of LRTI were registered (average: 1.9 cases/patient; range: 0-14). Gram-negative=59, gram-positive=26, and fungal=31 pathogens were detected, with polymicrobial samples in 46% of all cases. Increased number of LRTI was observed in the cold season (1.681.54 vs 0.79 +/- 0.92 case/month/patient, P<.01) and significant negative correlations were identified between the incidence of polymicrobial and bacterial infections and temperature (r(2)=0.1535, P<.05, r(2)=0.3144, P<.01, respectively). In addition, positive correlation was observed between polymicrobial infections and humidity (r(2)=0.1403, P<.05). Higher incidence of LRTI was also noted in the cold season, when accounting for the differences in immunosuppression. Conclusion: Seasons influenced the incidence of LRTI in the first postoperative year in LuTX recipients. More intensive vigilance for possible gram-negative and polymicrobial infections is needed in these patients in cold and wet seasons in the continental climate zone, regardless of underlying disease.