Isolation and identification of an Echovirus 11 in Guangzhou, Guangdong province in 2021

Objective To explore the isolation and identification of suspected enterovirus pathogen-infected specimens and understand the growth characteristics and evolutionary characteristics of Echovirus 11 (ECHO 11).

Methods  Enterovirus pathogens were identified through nested reverse transcription-polymerase chain reaction and one-step reverse transcription-polymerase chain reaction; Throat swab specimens were collected from children with fever and acute tonsillitis in Guangdong,GuangZhou in 2021 to isolate and culture the virus in human malignant embryonic rhabdomyosarcoma cells (RD), thereby studying the growth dynamics of the isolate in cells; According to the amplified full-length sequence of the VP1 gene of the isolate was amplified, a couple of globally representative epidemic strains were selected to draw an evolutionary tree. Based on the previous works, the genotype of the isolate was determined.

Results  The ECHO 11 strain was isolated from the patient’s throat swab specimen and named Qi-2023. The isolate can effectively proliferate in RD cells, with the virus titer increasing over time. The fastest increase occurred between 3 and 12 hours. The evolutionary tree analysis revealed that this isolate clustered with the D-type representative strain, and the nucleotide similarity of the VP1 gene ranged from 84.42% to 99.08%. The isolate showed the highest homology with the D5 subtype, with 99.08% nucleotide similarity in the VP1 gene.

Conclusion  A strain of ECHO 11, subtype D5, was successfully isolated from the throat swabs of patients with suspected enterovirus infection. These studies provide valuable laboratory data for the prevention and control of ECHO 11 infection.