title: A characterization of the oral microbiome in allogeneic stem cell transplant patients.
abstract: BACKGROUND
  The mouth is a complex biological structure inhabited by diverse bacterial communities. The purpose of this study is to describe the effects of allogeneic stem cell transplantation on the oral microbiota and to examine differences among those patients who acquired respiratory complications after transplantation.
  
  
  RESULTS
  All patients were consented at the National Institutes of Health, Clinical Center. Bacterial DNA was analyzed from patients' oral specimens using the Human Oral Microbe Identification Microarray. The specimens were collected from four oral sites in 45 allogeneic transplantation patients. Specimens were collected at baseline prior to transplantation, after transplantation at the nadir of the neutrophil count and after myeloid engraftment. If respiratory signs and symptoms developed, additional specimens were obtained. Patients were followed for 100 days post transplantation. Eleven patients' specimens were subjected to further statistical analysis. Many common bacterial genera, such as Streptococcus, Veillonella, Gemella, Granulicatella and Camplyobacter were identified as being present before and after transplantation. Five of 11 patients developed respiratory complications following transplantation and there was preliminary evidence that the oral microbiome changed in their oral specimens. Cluster analysis and principal component analysis revealed this change in the oral microbiota.
  
  
  CONCLUSIONS
  After allogeneic transplantation, the oral bacterial community's response to a new immune system was not apparent and many of the most common core oral taxa remained unaffected. However, the oral microbiome was affected in patients who developed respiratory signs and symptoms after transplantation. The association related to the change in the oral microbiota and respiratory complications after transplantation will be validated by future studies using high throughput molecular methods.
authors.affiliation: Clinical Center, Nursing and Patient Care Services, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Ames
authors.forename: Pawel
authors.initials: P
authors.lastname: Sulima
authors.forename: Thoi
authors.initials: T
authors.lastname: Ngo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Barb
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Munson
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Paster
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Hart
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification / Q000235:genetics*; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D064307:Microbiota / Q000235:genetics*; D008875:Middle Aged; D009055:Mouth / Q000382:microbiology*; D020411:Oligonucleotide Array Sequence Analysis; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012137:Respiratory System / Q000382:microbiology; D033581:Stem Cell Transplantation / Q000379:methods*; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: D012336:RNA, Ribosomal, 16S