Editor's note: the following is based on a presentation given at the 2024 Western Poultry Disease Conference.

It has been demonstrated that in ovo administration with virulent Enterococcus cecorum (EC) at day 18 of embryogenesis negatively impacts early performance and affected organs, like current EC outbreak reports in the field.

Since there is limited information regarding the prevalence, transmission and pathogenesis of early EC infections, the current investigation focused on developing a horizontal transmission model to simulate exposure to virulent EC during the hatching phase. The results of the study were presented by James Higuita and colleagues at the University of Arkansas and Mississippi State University.

Results suggest that exposure to EC via direct injection into the amnion during late embryogenesis or the hatching phase as infected chicks emerge from the egg, may increase EC colonization, promote extraintestinal lesions, and affect performance as early as 7 days post-hatch, depending on the strain.

E. cecorum isolation

Clinical presentation of (EC) disease in broilers is normally characterized by septicemia, lameness, and sometimes paralysis (chickens older than 4 weeks). The incidence of this disease has increased during the last years, noted Marcela Arango and colleagues at Mississippi State University.

EC-cpsO gene has been used to differentiate between pathogenic and commensal strains. The objective of this study was to differentiate between commensal and pathogenic EC isolates recovered from field cases.

Enterococcus spp isolates (N=299) recovered from cases submitted to laboratories (January to October 2023) were analyzed. Isolates came from broiler and layer breeders, hatcheries, broiler chickens, and commercial layers. Selected EC isolates (n=75) were analyzed phenotypically and genotypically to differentiate pathogenic and commensal strains.

The results of the study indicate:

1) EC has been recovered mainly from pericarditis and femoral head necrosis lesions in broilers.

2) EC was not isolated from any hatchery sample.

3) cpsO gene detection correlates with virulent EC isolates causing clinical disease and lesions.