The Oronasal Microbiota in Pediatric Oncology Patients

The human microbiome is composed of unique groups of microorganisms occupying distinct habitats distributed throughout the human body. The Human Microbiome Project recently evaluated the bacterial composition of the microbiome in 18 (for women) and 15 (for men) body sites. Much initial attention in the field of microbiome research has focused on the bacterial contribution to a "healthy" microbiome. However, it is clear that other microorganisms, including fungi and viruses, are also distributed throughout the human body and serve as functional components of the microbiome. The populations of microorganisms residing within the oral and nasal cavities make important contributions to human health and disease. These contributions may be especially important in immunosuppressed patients, including those patients receiving myelosuppressive chemotherapy or undergoing hematopoietic stem cell transplantation. In these patients, organisms typically considered as commensals can become pathogenic, either locally or systemically. This observational study is primarily undertaken to evaluate the oral and nasal microbiota and to define the population of fungal organisms residing within the oral and nasal cavities in pediatric oncology patients before and after receiving protocol-directed chemotherapy and associated supportive care.