Objective: To study the genotype of rotavirus and the genetic variations of the major neutralization antigen VP4 of group A rotavirus in fecal samples from infants with diarrhea in Chengdu, Sichuan province, China.
Methods: The fecal specimens were collected from infant patients with diarrhea in the spring of 2010 at West China Second University Hospital. Reverse transcription polymerase chain reaction (RT-PCR) was performed to identify rotavirus G serotypes and P genotypes. VP4 gene fragments of the virus were amplified from two strains drawn randomly from the prevailing genotype and cloned into a T-A clone vector to generate the recombinants for sequencing.
Results: A group rotaviruses were detected in 13 of 75 specimens (17.3%). Serotype G1 was the predominant type (7/13) and two were serotype G3, four strains' serotypes were unidentified. Analysis of P gene demonstrated that genotype P [8] was the predominant type (6/13), whereas only two P[4] genotype were detected and genotypes for two strains were not determined. G1P [8] was the predominant type of G/P dominance combination (5/13). Sequencing results of the VP4 gene for the analyzed two strains implied that they were genotype P[8] with a 97% homology in sequence. Compared with the standard strain, homologies were also more than 90%.
Conclusion: Rotavirus is one of the major etiological agents of viral diarrhea among infants in Chengdu. G1 was the dominant type G in Chengdu. G1P[8] was the predominant type of G/P dominance combination.