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Pulmonary infections in liver transplant recipients receiving tacrolimus. Changing pattern of microbial etiologies
N Singh1, T Gayowski, M Wagener
1Infectious Disease Section, VA Medical Center, Pittsburgh, Pennsylvania 15240, USA.
Abstract:
Pulmonary infections are a significant cause of morbidity after liver transplantation; Gram-negative bacilli, cytomegalovirus, and Pneumocystis carinii were the usual pulmonary pathogens in the earlier studies in liver transplant recipients receiving cyclosporine. We prospectively assessed the impact of pulmonary infection in 101 consecutive liver transplant recipients receiving the new immunosuppressive agent tacrolimus (FK506). Fifteen percent (15/101) of the patients had 19 episodes of pneumonia; 58% (11/19) of the pneumonias were bacterial, 37% (7/19) were fungal, and 5% (1/19) were protozoal (Toxoplasma gondii). Twenty-seven percent of the bacterial pneumonias were due to Legionella. None of the patients had cytomegalovirus or P carinii pneumonia. Seven percent (7/10) of the study patients had fungal pneumonitis; 4% had invasive aspergillosis and 3% had cryptococcosis. Mortality was significantly higher (53%, 8/15) for patients with pneumonia than for patients without pneumonia (10%, 9/86, P = 0.0004). Only fungal pneumonias were the direct cause of death; 63% (5/8) of the deaths were in patients with fungal pneumonitis. Our data suggest a changing pattern of microbial etiologies of pneumonitis in the era of modern immunosuppressive agents. We show that P carinii pneumonia and cytomegalovirus can be effectively curtailed with appropriate prophylaxis. Fungal infections, on the contrary, not only constituted a major proportion of the pneumonia, but also carried the highest pneumonia-associated mortality. Legionella infections can be overlooked unless specialized laboratory methodology (cultured on selective media, urinary antigen) are applied routinely on all cases of pneumonia. We recommend routine culture on the water supply for Legionella in all transplant centers.
Insights
Liver transplant recipients on tacrolimus face different pulmonary infections. Fungal pneumonias are common and deadly, unlike cytomegalovirus or Pneumocystis pneumonia, which are preventable.
Area of Science:
- Transplantation Medicine
- Infectious Diseases
- Pulmonology
Background:
- Pulmonary infections are a major cause of illness after liver transplantation.
- Previous studies identified Gram-negative bacilli, cytomegalovirus, and Pneumocystis carinii as common pathogens in cyclosporine-treated recipients.
- Tacrolimus (FK506) represents a newer immunosuppressive agent with potentially different infection profiles.
Purpose of the Study:
- To prospectively assess the impact and types of pulmonary infections in liver transplant recipients treated with tacrolimus.
- To identify changes in microbial etiologies of pneumonitis compared to earlier immunosuppressive regimens.
- To evaluate the mortality associated with different types of pneumonia post-liver transplantation.
Main Methods:
- Prospective study of 101 consecutive liver transplant recipients.
- Detailed monitoring and documentation of pulmonary infection episodes.
- Analysis of microbial causes, including bacterial, fungal, and protozoal pathogens.
- Comparison of mortality rates between patients with and without pneumonia.
Main Results:
- Fifteen percent of patients developed 19 episodes of pneumonia.
- Bacterial (58%) and fungal (37%) pneumonias were most common; no cytomegalovirus or P carinii pneumonia occurred.
- Fungal infections, particularly invasive aspergillosis and cryptococcosis, were significant.
- Mortality was substantially higher in patients with pneumonia (53%) versus those without (10%).
- Fungal pneumonias were the direct cause of death in most cases (63%).
Conclusions:
- Tacrolimus-based immunosuppression is associated with a changing pattern of pulmonary infections after liver transplantation.
- Prophylaxis effectively reduces Pneumocystis carinii and cytomegalovirus pneumonia.
- Fungal infections pose a significant threat, contributing to high mortality.
- Legionella should be considered, requiring specific diagnostic methods and water supply surveillance.