G-genotyping of rotaviruses in stool samples in Salento, Italy.

Rotaviruses are the most common agents of diarrhoeal illness in infants and young children. Gastroenteritis caused by rotaviruses is also more likely to be associated with severe dehydration compared to other viral gastroenteritis. We determined the G-genotype of rotaviruses circulating in the Salento. During 2004, 144 stool samples were collected from subjects with a positive screening test and stored at -20 degrees C until confirmation could take place using molecular biology techniques. A reverse transcription-polymerase chain reaction (RT-PCR) assay for the amplification of gene VP7 of rotavirus was developed and used; G-genotype was determined by sequencing and phylogenetic analysis. A total of 101 stool samples were detected positive by RT-PCR and 35 were sequence analyzed and classified into G1, G2, G4, G9 and G12 type. The overall relative incidence of G-types in Salento is different to that of other developed countries. The most prevalent genotype was G2 while genotype G1 was present at low levels. It is also interesting to note the presence of G9 rotavirus, which is now recognized as the fifth globally important rotavirus genotype. In this study, therefore, we demonstrate the usefulness of a simple method for correctly determining the G genotypes circulating in a geographic region