CHANGES IN THE ORAL STREPTOCOCCAL FLORA OF CHILDREN UNDERGOING ALLOGENEIC BONE-MARROW TRANSPLANTATION

The changes in the oral streptococcal flora of twenty children undergo ing allogeneic bone marrow transplant are described. Saliva was collec ted from each child on four separate occasions: (i) before the conditi oning regimen; (ii) 7 days post-transplantation; (iii) when the neutro phil count had risen above 0.5 x 10(9)/l; (iv) 119 days post-transplan tation. Indices for dental caries, plaque, gingivitis, herpetic stomat itis and mucositis were also recorded, There was a significant decreas e in the total aerobic (P<0.001) and anaerobic counts (P<0.0002) betwe en baseline and 7 days post-transplantation. The proportion of the 'St reptococcus oralis group' (Streptococcus mitis and S. oralis) increase d significantly from baseline 12.1% to 48.4% at 7 days post-transplant ation (P<0.003). The plaque and gingivitis indices increased significa ntly from baseline to 7 days post-transplantation (P<0.001). Twenty pe rcent of the children had either positive blood cultures or Hickman li ne cultures for the 'S. oralis group', and it is possible that the inf lamed gingival tissues are a further site of entry for these streptoco cci. There were no differences in the total anaerobic counts or the pr oportion of the 'S. oralis group' between baseline and the end of the study in the transplant children, or between the transplant and contro l children.