Development of serotype-specific PCR assays for typing of Haemophilus parasuis circulating in southern China.

5 years ago

Development of serotype-specific PCR assays for typing of Haemophilus parasuis circulating in southern China.

Xu Y, Zhou R, Liao M, Wang G, Zhang J, Fan H, Yang K, Jia A

The bacterium Haemophilus parasuis is the specific pathogenic cause of Glässer's disease in swine. Fifteen serotypes of H. parasuis have been reported. A method to serotype H. parasuis isolates accurately would help prevent and control Glässer's disease outbreaks through appropriate vaccination, and to understand the epidemiology in specific geographic areas. However, according to traditional serotyping, the rate of non-typeable (NT) strains is 10-40%, which gives low accuracy. In the present study, we developed a set of PCR assays that are able to identify all the currently known H. parasuis serotypes, with a detection limit of 5 colony-forming units. This PCR method is particularly useful to distinguish serotype 5 from serotype 12. We then surveyed the serotype prevalence of H. parasuis isolates from southern China using both the traditional indirect hemagglutination (IHA) and current PCR methods. Of the 298 isolates tested, 228 (76.51%) and 281 (94.30%) were serotyped by the IHA and PCR tests, respectively, with a concordance rate of 80.87% (241/298). The most prevalent serotypes obtained by PCR were 4, 5, 12, 13, NT, and 2; and those by IHA were NT, 5, 4, 12, 13, and 2. In conclusion, the PCR assays developed in this study provide a rapid and specific method for the molecular serotyping of H. parasuis.

Publisher URL: https://www.ncbi.nlm.nih.gov/pubmed/28878007

DOI: PubMed:28878007