Recurrent Pneumocystis carinii colonization in a heart-lung transplant recipient on long-term trimethoprim-sulfamethoxazole prophylaxis

Introduction: In the setting of organ transplantation, prior to prophylaxis, Pneumocystis carinii pneumonia (PCP) had been a common clinical problem, particularly in heart-lung and lung recipients who receive long-term immunosuppressive therapy to prevent allograft rejection. Continuous oral trimethoprim-sulfamethoxazole (TMP-SMX) has been highly effective in preventing PCP in these patients. Report: In this paper we report a case of recurrent Pneumocystis carinii infection in a chronic (> 15 years) heart-lung allograft recipient on long-term TMP-SMX prophylaxis. Twice, in 1995 and again in 1998, Pneumocystis carinii infection was diagnosed by bronchoalveolar lavage (BAL), in the same patient, despite continued oral TMP-SMX (960 mg TMP/4800 mg SMX per week) prophylaxis. The subject was not lymphopenic this CD4 count was 569/mm(3)) and there was no associated deterioration in pulmonary function, nor evidence of hypoxemia. Conclusion: This case demonstrates that asymptomatic Pneumocystis carinii lung infections may recur in chronic heart-lung transplant recipients who take standard oral PCP prophylaxis.