Association between virulence genes and serovars, sequence types of glaesserella (haemophilus) parasuis isolates from the nasal cavity of live piglets

Abstract

Th is study analyzed the 19 virulence genes (VGs) of 117 Glaesserella (Haemophilus) parasuis (G. parasuis) isolates from the nasal cavities of live piglets from the south of China and assessed the associations between VGs and serovars, sequence types (STs) of these isolates. Th e detection rate of 19 VGs ranged from 1.7% to 95.2%, with vacJ and clpP (95.7%) as the most prevalent. Of the 117 G. parasuis isolates, 105 were assigned to ten distinct serovars (1, 2, 4-10 and 15), and twelve of the isolates tested were non-typable (NT). Th e serovar 10 (17.9%) was the most prevalent. Th e G. parasuis isolates belonging to the same ST and serovar harbored diff erent VGs, and all isolates exhibited considerable genetic heterogeneity. Significant correlations were found between VGs and serovars, diff erent pathogenic serovar groups, and members of clade 2 (based on ST). Th e results complement epidemiological data of G. parasuis and will help the scientific community understand the extreme genetic diversity and pathogenesis of G. parasuis, which will aid in the development of G. parasuis vaccines.

Keywords

• glaesserella (haemophilus) parasuis
• virulence gene
• serovar
• st
• live piglet