Genotyping of adenoviruses isolated in an outbreak in a bone marrow transplant unit shows that diverse strains are involved.

In the Bone Marrow Transplant Unit of the "Centre Hospitalier Universitaire" in Nancy, from October 1995 to May 1996, 13 patients of 65 (20%) had a positive adenovirus (Ad) culture after bone marrow transplant. This unusually high rate raised fears of nosocomial spread and so isolates were serotyped. Fourteen Ad strains were isolated from the 13 patients, nine were of serotype 1, 2 or 3, and 5 were non-typable. These five latter strains were responsible for four cases of severe infection with fatal outcome within a two-month period. They were further submitted to restriction fragment length polymorphism analysis of their DNA which showed the isolates differed by a percentage similarity of 8-79%. In this outbreak, different strains were involved, and there was no evidence of a nosocomial origin of Ad infection.