Phylogenetic dendrograms based on nucleotide sequences were constructed and compared to previously reported G1, G2, G9 and G12 strains. Kolkata G1 strains

clustered in two subsets within two different lineages. One subset of G1 strains (BCK-2129/2011, BCK-2304/2011 and IDK-4418/2012) exhibited maximum similarities (>97%) with Thailand, India and Bangladesh G1 strains during BLAST analysis. Those strains remained in the same cluster within lineage I in phylogenetic dendrogram, though these were distant from the vaccine strains RotaTeq W179-9 and Rotarix A41CB052A (Fig. 3A). The other subset of G1 strains (IDK-4226/2011, BCK-2644/2012 and IDK-5042/2013) exhibited maximum similarities (>98%) with strains from Australia and Thailand. PARP inhibitor These G1 strains clustered with Rotarix

vaccine strain within lineage II (Fig. 3A), while the VP7 (G1) of Rotateq vaccine strain clusters in lineage III (Fig. 3A). All G2 strains (BCK-2601/2012, BCK-2409/2012, BCK-2953/2013, BCK-2852/2013, IDK-4292/2011, IDK-4599/2012 and IDK-5034/2013) showed 98–99% nucleotide similarities with previously reported strains from India, Nepal and Bangladesh Z-VAD-FMK and clustered in lineage IV. The G2 strains from this study were distant to RotaTeq vaccine strains in lineage II (Fig. 3B). Phylogenetic analysis showed all G9 strains from this study were in lineage III. Six of eight G9 strains (BCK-2168/2011, BCK-2679/2012, BCK-2934/2013, IDK-4321/2011, IDK-4957/2012

and IDK-5033/2013) revealed maximum identities (>96%) with previously reported human G9 strains from India and USA. These six G9 strains were in one subcluster, whereas, IDK-4176/2011 shared maximum homology with South African human G9 strain and BCK-2295/2011 was more similar with an American G9 strain. These two strains were placed in two other subclusters of lineage III (Fig. 4A). All the G9 strains from this study were found to be genetically distant from G9 vaccine strain 116E, which was in lineage II (Fig. 4A). The current G12 strains shared close nucleotide similarity (>95%) with previously reported Indian human lineage III G12 strains. Sample IDK-5082/2013 formed distant mafosfamide subcluster, whereas other three (BCK-2783/2012, BCK-2907/2013 and IDK-5095/2013) formed another subcluster with Indian, Nepalese and Belgian G12 strains within lineage III (Fig. 4B). The amino acid homology of the current circulating strains was compared to the vaccine strains. The lineage II G1 strains were similar (92–95%) to Rotarix-G1 strain which also clustered in lineage II (Fig. 3A), but lineage I G1 strains had 91–94% homology to either Rotarix-G1 or RotaTeq-G1 strains (Table 3). Amino acid homology of G2 strains with RotaTeq G2 was ∼91%, whereas Kolkata G9 strains showed 89–92% amino acid homology with 116E-G9 vaccine strains (Table 3). The VP7 trimer contains two structurally defined antigenic epitopes: 7-1 and 7-2.