Molecular analysis ofVP4,VP7, andNSP4 genes of P[6]G2 rotavirus genotype strains recovered from neonates admitted to hospital in Belém, Brazil

Abstract

This investigation describes the molecular characterization of P[6]G2 rotavirus strains from hospitalized neonates with community-acquired diarrhea (CAD), nosocomial diarrhea (ND), and asymptomatic nosocomial infection (ANI) in Belém, Brazil. Twenty-six rotavirus strains with P[6]G2 genotype were sequenced to genes coding for VP4, VP7, and NSP4 proteins. Phylogenetic analysis of the VP4 gene, including prototype strains RV3, ST3, M37, and U1205, showed that local P[6]G2 strains clustered forming a distinct lineage (bootstrap of 99%). Brazilian P[6]G2 strains had the highest homology (ranging from 96.0%-98.3%) with the African strain GR1107, G4P[6]. Phylogenetic tree for VP7 gene was constructed including old and new G2 African strains SA3958GR/97, SA356PT/96, SA514GR/87, SA4476PT/97, BF3676/99, GH1803/99, and representative strains of G1, G3, G4, G5, G8, and G9 genotypes. The Brazilian P[6]G2 samples fell into a distinct group (bootstrap value of 97%) and showed homology rates ranging from 92.1% to 93.5% with P[6]G2 African strains BF3676/99, GH1803/99, and SA3958GR/97. Nucleotide sequence analysis of the NSP4 gene, including human prototype strains S2, KUN, DS-1, RV5, RV3 and ST3, and animal prototype OSU, showed that all neonatal isolates fell into genotype A and clustered with a bootstrap value of 100%, with in-group similarities ranging from 99.3% to 100%. In this study no significant differences in nucleotide sequences of the VP4, VP7, and NSP4 genes could be observed when comparing diarrheic (CAD and ND) and non-diarrheic (ANI) babies. Monitoring of rotavirus strains in hospital environments is of particular importance, since it is claimed currently that an efficacious rotavirus vaccine, when available for routine use, will determine an impact on hospital-acquired rotavirus disease.

Multiple‐gene characterization of rotavirus strains: Evidence of genetic linkage among the VP7‐, VP4‐, VP6‐, and NSP4‐encoding genes

“…The results presented above suggest a linkage among all four genes analyzed because genotypes G1/G3/G4/G5/G9-P[8] were strongly correlated to I1-E1 genotypes and G2-P[4]/P[6] was correlated to I2-E2 genotypes. The same correlation among those genes has been suggested by other investigators [Mascarenhas et al, 2006Rodríguez-Díaz et al, 2008;Tavares et al, 2008]. Yet, the results also suggest that all four genes can segregate independently in reassorted strains, as in the case of strains bearing G9-P[4]-I1-E2 or G9-P[9]-I1-E2 specificity.…”

Identification of two sublineages of genotype G2 rotavirus among diarrheic children in Parauapebas, Southern Pará State, Brazil

“…During surveillance for rotavirus infection [Mascarenhas et al, 2006], conducted from May 1996 to May 1998 in neonatal care unit wards at a public hospital in Belém, Brazil, three neonatal strains (NB-301, NB-162, and NB-308) clustered into other new sublineage, named II-d. In addition, the sample HST-369, collected in 1999 from diarrheic children with diarrhea during a 2-year surveillance study in Belém, Brazil [Mascarenhas et al, 2007], clustered into lineage III.…”

“…The nucleotide sequencing was carried out as reported by Mascarenhas et al [2006], using the primers 9con1/ 9con2 and 4con3/4con2 and the Big Dye Terminator Cycle Sequencing Ready Reaction kit (Applied Biosystems, Foster City, CA). The products were analyzed using an automatic ABI Prism 3100 DNA sequencer (Applied Biosystems).…”

“…Also, other epidemiological studies carried out in Belém, Northern Brazil demonstrated the variability of antigenic and genetic diversity of rotavirus strains showing a higher frequency of mixed infections and unusual genotypes [Gusmã o et al, 1999;Linhares and Bresee, 2000;Mascarenhas et al, 2002Mascarenhas et al, , 2006Mascarenhas et al, , 2007.…”

Histo-blood group antigens as receptors for rotavirus, new understanding on rotavirus epidemiology and vaccine strategy

“…50, 51, 52 In addition, P[6] RVs are commonly found in animals (porcine), neonates and young infants; where infected neonates and young infants may be asymptomatic. 53, 54, 55 Interestingly, the P[6] VP8* did not bind adult saliva, but interacted with neonate and young infants' saliva, 39 and type 1 HBGA chains with or without the H epitope, including type 1 HBGA precursors without further terminal Lewis fucose modifications, 35, 39 leading to the hypothesis that similar to P[11] RVs, P[6] has an age-specific host range and cross-species transmission between humans and animals (see below).…”