Rapid subgenus identification of human adenovirus isolates by a general PCR

In most clinical situations involving adenovirus infection, subgenus (subgroup) identification of an adenovirus isolate is as informative as a finer identification by serotype. A PCR method which allows the identification of human adenovirus isolates as members of subgenera A, B:1, B:2, C, D, E, or F is described. It is based on a simple (nonnested) PCR using primers which bind to regions immediately flanking the VA RNA-encoding regions of human adenovirus genomes. The PCR allows amplification of DNA from all 49 human adenovirus prototype strains so far described. Since there are differences in the lengths of the VA RNA-encoding regions in adenoviruses of different subgenera, it is possible to differentiate some subgenera according to the size of the PCR product determined by electrophoresis. This forms the basis of an initial broad categorization of isolates as belonging to either (i) subgenus B:1, C, D, or E or (ii) subgenus A, B:2, or F. Subgenus identification is completed by a one-step restriction enzyme digestion and gel electrophoresis. The method was assessed by blind subgenus identification of 200 miscellaneous primate adenovirus isolates prepared by the reference laboratory at Bilthoven, The Netherlands. Identification at the subgenus level by PCR correlated 91.5% with the results of serotyping. A further 5.5% of isolates were correctly identified as belonging to one of two specified subgenera. Six of the 200 identifications (3%) were unsuccessful for various reasons, including weak PCR products, intermediate strains, and mistaken primate host. The method should serve as a rapid means of confirming adenovirus cytopathic effects in laboratories performing virus culture, with simultaneous subgenus identification of the isolate. It will also have relevance as an aid to conventional serotyping for epidemiological purposes, since for all adenoviruses except those belonging to subgenus D, neutralization tests need only involve a maximum of four type-specific antisera.