Prophylaxis of infection in bone marrow transplants

Bone marrow transplants experience severe immuno-deficiency as a consequence of pretransplant radiation and chemotherapy, transient granulocytopenia before marrow engraftment, and post-transplant prevention and treatment of graft-versus-host disease with immuno-suppressive agents. During periods of granulocytopenia, chemoprophylaxis with the oral fluorinated quinolones can prevent colonization and infection with gram-negative bacilli, is better tolerated than oral non-absorbable antibiotics or trimethoprim-sulfamethoxazole and is more cost-effective than laminar-air-flow isolation or prophylactic granulocyte transfusions. Antifungal prophylaxis with oral nystatin, ketoconazole or amphotericin B, however, has not been consistently effective; empiric intravenous amphotericin B therapy is still the most reliable way to prevent fatal fungal infections. Following marrow engraftment, cytomegalovirus infection and interstitial pneumonia can be prevented in cytomegalovirus-seronegative patients by the use of cytomegalovirus-seronegative blood products and cytomegalovirus immune globulin. In cytomegalovirus-seropositive patients, prophylactic DHPG (ganciclovir) is currently being evaluated in a controlled clinical trial. Herpes simplex and varicella-zoster infections can be treated effectively with intravenous acyclovir, but routine acyclovir prophylaxis is not cost-effective. Trimethoprim-sulfamethoxazole is used for prophylaxis of Pneumocystis carinii pneumonia and may be continued in patients with chronic graft-versus-host disease for prevention of late post-transplant bacterial infections.