A characterization of the oral microbiome in allogeneic stem cell transplant patients.

Nancy J Ames,Peter J Munson,Thoi Ngo,Thomas C Hart,Jennifer Barb,Bruce J Paster,Pawel Sulima

doi:10.1371/journal.pone.0047628

Abstract

BackgroundThe 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.Methodology/Principal FindingsAll 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/SignificanceAfter 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.

Highlights

The oral microbiome is one of the most complex bacterial communities within the human microbiome
Of the 113 specimens analyzed, 61 were from patients who did not develop respiratory signs and symptoms post-transplantation and 52 specimens were from patients who developed this complication after transplantation
The risk of periodontitis was low in the sample, but gingivitis was present in all eleven patients

Summary

Introduction

The oral microbiome is one of the most complex bacterial communities within the human microbiome. Supragingival plaque is present on teeth and supports a distinctive bacterial community [1] This plaque biofilm represents an entire body of research and has been described in numerous studies as related to major dental pathologies, caries and periodontitis and linked to health and pulmonary infection [2,3,4,5,6]. Add to this a complex fluid, saliva, that irrigates the oral cavity and it is not surprising that the oral microbiome eludes a complete characterization. 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

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Conclusion