Abstract
Haemophilus parasuis (H. parasuis) is a common commensal Gram-negative extracellular bacterium in the upper respiratory tract of swine, which can cause Glässer's disease in stress conditions. Research on the pathogenicity of H. parasuis has mainly focused on immune evasion and bacterial virulence factors, while few studies have examined the interactions of H. parasuis and its host. Autophagy is associated with the replication and proliferation of many pathogenic bacteria, but whether it plays a role during infection by H. parasuis is unknown. In this study, an adenovirus construct expressing GFP, RFP, and LC3 was used to infect H. parasuis. Western blotting, laser confocal microscopy, and electron microscopy showed that Hps5 infection induced obvious autophagy in PK-15 cells. In cells infected with strains of H. parasuis differing in invasiveness, the levels of autophagy were positively correlated with the presence of alive bacteria in PK-15 cells. In addition, autophagy inhibited the invasion of Hps5 in PK-15 cells. Autophagy related genes Beclin, Atg5 and Atg7 were silenced with RNA interference, the results showed that autophagy induced by H. parasuis infection is a classical pathway. Our observations demonstrate that H. parasuis can induce autophagy and that the levels of autophagy are associated with the presence of alive bacteria in cells, which opened novel avenues to further our understanding of H. parasuis-host interplay and pathogenesis.
Highlights
Haemophilus parasuis (H. parasuis) is the etiological agent of Glässer’s disease in swine, a systemic disease presenting as porcine polyserositis, polyarthritis and meningitis (Oliveira and Pijoan, 2004; Costa-Hurtado et al, 2013)
Most studies of bacterial autophagy have focused on intracellular pathogens, such as Mycobacterium tuberculosis (Kimmey et al, 2015) and Brucella, but extracellular pathogens such as Pseudomonas aeruginosa (Yuan et al, 2012) and Acinetobacter baumannii (Rumbo et al, 2014) are known to induce autophagy through cell invasion
In this study we examined the relationship between autophagy and H. parasuis infection
Summary
Haemophilus parasuis (H. parasuis) is the etiological agent of Glässer’s disease in swine, a systemic disease presenting as porcine polyserositis, polyarthritis and meningitis (Oliveira and Pijoan, 2004; Costa-Hurtado et al, 2013). Glässer’s disease causes significant economic losses to the swine. H. parasuis strains have been classified into 15 standard serotypes according to agar-gel-precipitation tests (AGPT) (Morozumi and Nicolet, 1986). Strains of H. parasuis are heterogeneous and differ in virulence (Kielstein and Rapp-Gabrielson, 1992). Serovars 1, 5, 10, 12, 13, and 14 are considered highly virulent and cause high mortality in pigs. Serovars 2, 4, 8, and 15 are less virulent, and 3, 6, 7, 9, and 11 are classified as avirulent (Kielstein and RappGabrielson, 1992; Nielsen, 1993). Each H. parasuis serotype is associated with a characteristic level of virulence, the specific features that contribute to pathogenesis remain elusive
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
