title: Characterization of Chinese Haemophilus parasuis Isolates by Traditional Serotyping and Molecular Serotyping Methods.
abstract: Haemophilus parasuis is classified mainly through serotyping, but traditional serotyping always yields non-typable (NT) strains and unreliable results via cross-reactions. Here, we surveyed the serotype prevalence of Chinese H. parasuis isolates using traditional serotyping (gel immuno-diffusion test, GID) and molecular serotyping (multiplex PCR, mPCR). We also investigated why discrepant results between these methods were obtained, and investigated mPCR failure through whole-genome sequencing. Of the 100 isolate tested, 73 (73%) and 93 (93%) were serotyped by the GID test and mPCR, respectively, with a concordance rate of 66% (66/100). Additionally, mPCR reduced the number of NT isolates from 27 (27%) for the GID testing, to seven (7%). Eleven isolates were sequenced, including nine serotype-discrepant isolates from mPCR and GID typing (excluding strains that were NT by GID only) and two NT isolates from both methods, and their in silico serotypes were obtained from genome sequencing based on their capsule loci. The mPCR results were supported by the in silico serotyping of the seven serotype-discrepant isolates. The discrepant results and NT isolates determined by mPCR were attributed to deletions and unknown sequences in the serotype-specific region of each capsule locus. Compared with previous investigations, this study found a similar predominant serotype profile, but a different prevalence frequency for H. parasuis, and the five most prevalent serotypes or strain groups were serotypes 5, 4, NT, 7 and 13 for mPCR, and serotypes 5, NT, 4, 7 and 13/10/14 for GID. Additionally, serotype 7 was recognized as a principal serotype in this work.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Yuefeng
authors.initials: Y
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Xuerui
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Zhongxin
authors.initials: Z
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Jixing
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D002681:China; D003198:Computer Simulation; D016680:Genome, Bacterial; D044137:Haemophilus parasuis / Q000145:classification* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012703:Serotyping / Q000379:methods*; D013552:Swine / Q000382:microbiology