Effects of bacterial naso-oropharyngeal colonisation on acute graft-versus-host disease in patients undergoing allogeneic bone marrow transplantation.

The efficacy of gastrointestinal decontamination in reducing the incidence of severe bacterial or fungal infections and of moderate to severe acute graft-versus-host disease (GVHD) has been suggested. We report here a retrospective study of 71 patients grafted consecutively in our institution with bone marrow from HLA genotypically identical siblings. Complete decontamination (plastic isolator or laminar airflow room, sterile nursing and oral antimicrobial drugs) was carried out in all patients. Sixty eight patients were evaluable. Only six patients had aerobic Gram negative rods or anaerobic bacteria in their faeces and 44 of 68 (65%) had yeasts in their faeces. Most patients had oropharyngeal and/or nasal colonisation with bacteria (Gram positive cocci: 39 patients (57%); Gram negative rods: 13 patients (19%)) or yeasts (29 patients (43%)). Thirty nine patients (57%) experienced severe grade > or = II acute GVHD (grade II-IV). A significant relation was found between bacterial oropharyngeal or nasal colonisation and GVHD (P < 0.01) but not between gastrointestinal microflora and GVHD, whatever microorganisms were considered (bacteria, yeasts).