Vaccination of breeder hens with a polyvalent killed vaccine for pathogenicEnterococcus cecorumdoes not protect offspring from enterococcal spondylitis

Abstract

Pathogenic strains of Enterococcus cecorum cause symmetrical paralysis in broilers due to infection of the free thoracic vertebra. The disease caused by pathogenic E. cecorum, known as enterococcal spondylitis or "kinky-back" continues to be responsible for significant losses to the broiler industry worldwide. In outbreaks of pathogenic E. cecorum, gut colonization and sepsis occur in the first three weeks-of-life. Since maternal antibodies are present during this period, we postulated that vaccination of breeders with a polyvalent killed vaccine would protect chicks from challenge. To test this hypothesis, representative isolates from seven genotype groups of pathogenic E. cecorum circulating in the US were chosen to produce adjuvanted killed vaccines (bacterins) and given to broiler-breeder hens. No single strain produced high titres of antibodies to all other strains; however, the combination of serologic reactivity of pathogenic isolates (designated SA3 and SA7) was sufficient to react with all genotypes. Vaccination of commercial broiler-breeder hens with a bacterin composed of SA3 and SA7 did not have any adverse effects. Vaccinated hens developed E. cecorum specific antibodies; however, no significant difference in survival was observed in infected embryos from hens in vaccine or adjuvant only groups. Chicks from vaccinated hens also failed to resist homologous or heterologous challenge during experimental infection. In a macrophage killing assay, pathogenic E. cecorum were found to evade opsinophagocytosis with elicited antibodies. These data suggest that pathogenic strains of E. cecorum possess virulence mechanisms that confound antibody-mediated opsinophagocytosis, complicating vaccine development for this pathogen of broilers.

Antimicrobial resistance in the globalized food chain: a One Health perspective applied to the poultry industry

“…E. cecorum has grown in importance from the past two decades after the epidemic of pathogenic strains in broilers, causing the so-called free thoracic vertebra (FTV) osteomyelitis [ 87 ]. The infection causes abscesses in the thoracic vertebrae that compress the spinal cord, leading the bird to remain supported under the tibiotarso-tarsometatarsal joint resulting from symmetrical paralysis of the posterior limbs [ 88 , 89 ]. In addition, septicemia may occur with the appearance of fibrinoid pericarditis, hepatitis, and splenomegaly, which can progress to death [ 90 ].…”

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): antimicrobial‐resistant Enterococcus cecorum in poultry

“…There are no effective commercially available vaccines yet, but flock‐specific autogenous vaccines may be applied in broiler breeder flocks. Maternal antibodies may be transferred to the offspring; however, no protection against E. cecorum challenge has been demonstrated, even with a vaccine composed of antigens from seven genotype groups, which induced a good opsonisation response (Borst et al, 2019a).…”

“…No protection against E . cecorum challenge has been demonstrated, even with a vaccine composed of antigens from seven genotype groups which induced a good opsonisation response (Borst et al, 2019a).…”

Разработка И Оценка Специфической Эффектив-Ности Вакцины Против Энтерококкоза Сельскохозяй-Ственной Птицы

“…(33) также доказали возможность эффективной борьбы с энтерококкозом посредством использования инактивированных вакцин на поголовье товарного бройлера. При этом авторы отмечают, что антигенный состав EC может быть представлен несколькими гетерологичными серотипами, не проявляющими перекрестную антигенную активность, ввиду чего эффективность вакцинного препарата из одного серотипа оказалась низкой (33). В других работах было установлено существование как минимум семи групп генотипов EC и их разделение на две серологические группы (38,41), для борьбы с которыми предложены инактивированные поливалентные вакцины из двух штаммов Enterococcus cecorum (33).…”