Genomic characterization and molecular investigation of VP7 epitopes of uncommon G10P[8] group A rotavirus strains detected in Italy in 2009

Rotavirus strains with the uncommon genotype G10 have been detected sporadically in cases of acute gastroenteritis in humans and are thought to be transmitted zoonotically. During 2009, 10 G10P[8] rotavirus strains were detected in the stools of children hospitalized with acute diarrhoea in several paediatric hospitals in Italy. The phylogenetic analysis of the VP7 gene of the Italian G10P[8] strains analysed revealed nucleotide identities ranging from 94 to 99 %. Molecular characterization of the 11 genomic segments was performed for one of the G10 strains, which displayed a complete genomic constellation 1 for the non-G genes. The analysis of the deduced amino acid sequences of the G10 VP7 epitopes revealed low amino acid identity with common human strains of different G genotype and with the VP7 proteins included in both anti-rotavirus commercial vaccines (Rotarix and RotaTeq). Amongst the common G genotypes, the VP7 amino acid sequence of the G10 strains showed a high similarity with sequences from G9 strains. A hydrophobic cluster analysis (HCA) of the VP7 protein including aa 20-298 was performed for the G10 Italian sequences in comparison with the major human group A rotavirus G genotypes. The HCA analysis confirmed the findings obtained previously by amino acid analysis of the VP7 epitopes, detecting a genotype-specific pattern of hydrophobicity in the hypervariable regions of the major outer capsid protein.