Genetic diversity of G9P[8] rotavirus strains circulating in Italy in 2007 and 2010 as determined by whole genome sequencing

•We sequenced the full genome of four unrelated G9P[8] rotaviruses in Italy, 2007-2010.•All G9P[8] rotaviruses shared a Wa-like genotype constellation.•Phylogenetic data revealed multiple intra-genotype clusters for most gene segments.•Phylogenetic analysis suggested genetic drift not excluding segment reassortment.•Amino acid changes in VP4 and VP7 neutralization sites were detected between strains.

This study reports the molecular characterization of G9P[8] rotavirus strains from children with acute diarrhea identified in different cities of Italy, in 2007 and 2010. Seventeen samples exhibited a G9P[8] genotype by RT-PCR and semi-nested PCR. Preliminary sequence analysis of the VP7 and VP8* encoding genes revealed nucleotide identities ranging between 96% and 100%. Full genome sequencing of four G9P[8] strains selected in different cities or years showed that the investigated Italian strains possessed a complete Wa-like genotype constellation. However, phylogenetic analyses assigned strains to different clusters reflecting point mutations and possibly earlier reassortment between Wa-like RVA strains. Deduced amino acid sequence of the VP7 and VP4 genes for the G9P[8] strains revealed at least five substitutions in relevant antigenic sites of both proteins.