Objective To analyze the genetic characteristics of a recombinant strain of human adenovirus C5 and C89 (LN2017022) isolated from the stool sample of an acute flaccid paralysis (AFP) case in Liaoning province, and provide theoretical evidence for human adenovirus surveillance and vaccine development.

Methods The genome sequence of the LN2017022 strain was sequenced. Then, phylogenetic trees based on the whole genome, Penton base, Hexon, Fiber, and E3 gene sequences were constructed using the Neighbor-Joining (NJ) method in software MEGA 7.0 for analysis on the nucleotide and amino acid mutations of LN2017022 based on 27 full genome sequences of human adenovirus C5 (HAdV-C5) downloaded from GenBank. Recombination analysis on LN2017022 strain was performed using RDP 4.0 and SimPlot 3.5.1.

Results The whole genome length of LN2017022 strain was 35 854 bp. It had the same amino acid deletions (A363 and P364) as HAdV-C89 on the RGD loop of the Penton base, and a unique amino acid mutation (P153H) on HVR1 different from HAdV-C89. Compared with HAdV-C5 prototype, the Hexon gene had only one unique mutation (C1176T) at locus 1176, which was a synonymous mutation. The Fiber gene was highly conserved. LN2017022 strain was a new recombinant genotype of P89H5F5. The phylogenetic analysis on the full genome demonstrates that HAdV-5 can be divided into 2 lineages, 1 and 2, and lineage 1 has 3 clades, and LN2017022 belonged to clade 2, but the Penton base genotype belonged to HAdV-C89, indicating that intra group recombination occurred in the HAdV-5 strain.

Conclusion The genome of HAdV-C5 has undergone significant genetic variation and recombination, and the surveillance and research of HAdV-C5-caused disease should be strengthened in the future.