As depicted in Fig. 1, the 2007 outbreak strains formed a distinct cluster within G9 VP7 Lineage III, sub-lineage D. The strains in Lineage III exhibited 93.3-99.1% nucleotide identity

to the Alice Springs outbreak samples. The 2007 outbreak strains exhibited closest similarity to a G9P[8] strain isolated in Brazil in 2006, with 99.0–99.1% nucleotide similarity and 99.8–99.9% amino acid identity. PD0332991 Comparison of the deduced amino acid sequences of the VP7 genes from the 2007 outbreak strains with VP7 from G9P[8] strains previously identified in Australia also revealed a close relationship with the previous circulating Australian G9P[8] strains in Lineage III, with a 98.0–98.7% nucleotide and 94.0–96.3% amino acid sequence similarity observed. Three conserved amino acid substitutions were identified at positions 44 (Ala/Val-Thr), 263 (Val-Ile) and 279 (Ala-Thr) in the GSK1210151A solubility dmso 2007 outbreak strains when compared to other G9 strains analysed. A 663 bp region of the VP8* subunit of the VP4 gene was sequenced for six G9P[8] samples, including three from vaccinated infants.

The sequences were highly conserved with 99.6–100% nucleotide identity and 98.7% amino acid homology observed. No conserved nucleotide or amino acid changes were observed between samples obtained from vaccinated and non-vaccinated patients. Phylogenetic analysis of the nucleotide sequence of the VP8* subunit of the G9P[8] 2007 outbreak strains and previously published P[8] human strains was performed. As depicted in Fig. 2, through the 2007 outbreak strains formed a distinct cluster within P[8] Lineage 3 (P[8]-3). The strains in P[8] Lineage 3 exhibited 97.3–99.7%

nucleotide identity to the Alice Springs outbreak samples. The 2007 outbreak strains revealed close similarity to G9P[8] strains isolated in the USA, Russia and Ireland, displaying 98.6–99.3% nucleotide and 97.0–99.1% amino acid identity. When compared to a 2001 Australian G9P[8] isolate, the outbreak strains exhibited 98.3–98.6% nucleotide and 97.8–98.7% amino acid identity. The 2007 outbreak strains contained two unique amino acid substitutions at positions 237 (Ser-Leu) and 242 (Thr-Ser) when compared to all other P[8] strains analysed. The 750 bp of the NSP4 gene was sequenced for 14 G9P[8] outbreak strains including three from vaccinated infants. The sequences were all highly conserved displaying 99.4–100% nucleotide and 99.9–100% amino acid identity. No conserved changes were observed between samples obtained from vaccinated and non-vaccinated patients. Phylogenetic analysis of the nucleotide sequence of the NSP4 gene of the G9P[8] 2007 outbreak strains and previously published NSP4 genes was performed. As depicted in Fig. 3, the NSP4 from the 2007 outbreak strains formed a distinct cluster within the E1 Genogroup. The strains in E1 Genogroup exhibited 90.6–99.