Etiologies, risk factors, and outcomes of bacterial pneumonia after living donor liver transplantation

The prevalence and clinical characteristics of bacterial pneumonia after living donor liver transplantation (LDLT) have not yet been elucidated. We performed a retrospective analysis of 346 LDLT recipients. Fifty patients (14.5%) experienced bacterial pneumonia after LDLT, and they had a higher short-term mortality rate (42.0%) than patients with other types of bacterial infections after LDLT. Gram-negative bacteria accounted for 84.0% of the causative pathogens. A multivariate analysis showed that preoperative diabetes (P < 0.01), United Network for Organ Sharing status 1 or 2A (P < 0.01), and an operative blood loss > 10 L (P = 0.03) were significant risk factors for bacterial pneumonia after LDLT. Post-LDLT pneumonia was associated with the following post-LDLT events: the prolonged use of mechanical ventilation (≥3 days), a prolonged stay in the intensive care unit (≥7 days), the creation of a tracheostomy, primary graft dysfunction, the use of mycophenolate mofetil, and the need for renal replacement therapy. Among patients with bacterial pneumonia, the mortality rate was higher for patients with delayed-onset pneumonia, which occurred at least 10 days after transplantation (n = 15), and it was significantly associated with graft dysfunction. A combination of broad-spectrum antibiotics and aminoglycosides provided cover for most gram-negative bacteria except Stenotrophomonas maltophilia, which was associated with a longer period of mechanical ventilation and was resistant to commonly used broad-spectrum antibiotics. Delayed-onset bacterial pneumonia is a serious type of bacterial infection after LDLT and is frequently associated with graft dysfunction. The multidrug resistance of S. maltophilia is an issue that needs to be addressed.