title: Group B strains of human respiratory syncytial virus in Saudi Arabia: molecular and phylogenetic analysis.
abstract: The genetic variability and circulation pattern of human respiratory syncytial virus group B (HRSV-B) strains, identified in Riyadh during the winters of 2008 and 2009, were evaluated by partial sequencing of the attachment (G) protein gene. The second hypervariable region (HVR-2) of G gene was amplified by RT-PCR, sequenced and compared to representatives of different HRSV-B genotypes. Sequence and phylogenetic analysis revealed that all Saudi strains belonged to the genotype BA, which is characterized by 60-nucleotide duplication at HVR-2. Only strains of 2008 were clustered with subgroup BA-IV, while those isolated at 2009 were clustered among the most recent subgroups (particularly BA-X and CB-B). Amino acid sequence analysis demonstrated 18 amino acid substitutions in Saudi HRSV-B strains; among which five are specific for individual strains. Furthermore, two potential N-glycosylation sites at residues 230 and 296 were identified for all Saudi strains, and an additional site at amino acid 273 was found only in Riyadh 28/2008 strain. O-glycosylation was predicted in 42-43 sites, where the majority (no = 38) are highly conserved among Saudi strains. The average ratio between non-synonymous and synonymous mutations (ω) implied stabilizing selection pressure on G protein, with evidences of positive selection on certain Saudi strains. This report provides preliminary data on the circulation pattern and molecular characteristics of HRSV-B strains circulating in Saudi Arabia.
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia, majhdi@ksu.edu.sa.
authors.forename: Fahad N
authors.initials: FN
authors.lastname: Almajhdi
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Farrag
authors.forename: Haitham M
authors.initials: HM
authors.lastname: Amer
mesh_terms: D005814:Genes, Viral; D006031:Glycosylation; D006801:Humans; D010802:Phylogeny; D012136:Respiratory Syncytial Viruses / Q000235:genetics / Q000302:isolation & purification*; D012529:Saudi Arabia