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.