Putative Riemerella anatipestifer Outer Membrane Protein H Affects Virulence

Abstract

Riemerella anatipestifer causes serious contagious disease in ducks, geese, and other fowl. However, as a harmful pathogen causing significant economic losses in the poultry industry, R. anatipestifer is still poorly understood for its pathogenesis mechanisms. In a previous study, we developed an indirect ELISA method for detecting R. anatipestifer infection using B739_0832 protein, a putative outer membrane protein H (OmpH) that is conserved among different serotypes of R. anatipestifer. Although OmpH in some pathogenic bacteria, such as Pasteurella, has been reported as a virulence factor, it is still not clear whether B739_0832 protein contributes to the virulence of R. anatipestifer. In this study, we confirmed that B739_0832 protein in R. anatipestifer localizes to the outer membrane. We constructed a B739_0832 deletion mutant strain (ΔB739_0832) and assayed various effects from the deletion of B739_0832. ΔB739_0832 strain had a similar growth rate to wild-type R. anatipestifer CH-1. However, the survival rate of ducklings in 10 days after infection from ΔB739_0832 strain was 50%, whereas no ducklings survived from wild-type R. anatipestifer infection. Furthermore, the median lethal dose (LD50) of the ΔB739_0832 strain was approximately 150 times higher than that of the wild-type strain. Pathology examinations on infected ducklings found that, at 36 h after infection, bacterial loads in blood, liver, and brain tissues from ΔB739_0832-infected ducklings were considerably lower than those from wild-type infected ducklings. These results demonstrate that the B739_0832 protein contributes to the virulence of R. anatipestifer CH-1.

Research Note: Antibiotic resistance and pathogenicity of geese-derived Riemerella anatipestifer isolated from eastern regions of Hebei Province, China

“…Infectious serositis is an acute, septic, and devastating bacterial disease in susceptible poultry, which often appears in birds under 2 mo old and causes substantial mortality ( Gao et al, 2021 ), and R. anatipestifer was reported to be the causative agent. In 2022, an extensive outbreak of infectious serositis occurred in farmed geese in eastern Hebei Province, causing large-scale deaths and significant losses.…”

Characterization of Campylobacter jejuni proteome profiles in co-incubation scenarios

“…Putative lipoproteins can be considered as virulence factors, as well. Many outer membrane proteins in pathogenic bacteria are virulence factors that enable or facilitate bacterial attachment to host cell surfaces (Gao et al, 2021). The exact function of the putative membrane protein remains unknown.…”

Evaluation and development of diagnostic tools for rapid detection of Riemerella anatipestifer and Pasteurella multocida in ducks

“…This isolation rate was lower than the level reported by El-Hamid et al [ 25 ] and Shalaby et al [ 6 ]. While higher prevalence rates reaching 50 % were detected in China and India [ 26 ]. This difference may be attributed to the variations in ducks’ age and breeds, sample number, isolation protocol, stress, geographical location, and resistance power of ducklings due to management, vaccine, and nutrition.…”