Bacterial and fungal infections in children undergoing bone marrow transplantation.

Bacterial and fungal infections in pediatric BMT recipients are major causes of morbidity and mortality, although less than those in the adult BMT population. Early in the post-BMT period, when patients are neutropenic, the predominant pathogens are Gram-negative bacteria, mainly E. coli, K. pneumoniae and P. aeruginosa; Gram-positive bacteria, mainly coagulase-negative staphylococcus, S. viridans and E. faecalis; and fungi, mainly Candida spp. and Aspergillus spp. The emerging resistance of a variety of pathogens is of major concern and limits the use of prophylactic antibiotics. Mortality from invasive fungal infections is much greater than that caused by bacterial pathogens. Many centers are currently using prophylactic fluconazole, which may lead to emergence of infections with C. krusei and T. glabrata. Patients with GvHD are at continuous risk from bacterial and fungal pathogens. Late in the post-BMT period, S. pneumoniae may cause septicemia, meningitis, pneumonia and other respiratory infections. This may occur months or years following transplantation, with a significant mortality rate in patients with chronic GvHD. Development of rapid and reliable diagnostic methods for identifying fungal pathogens and of new therapeutic approaches for treating invasive fungal infections are now our greatest future challenges.