title: Pathogenesis of Enterococcal Spondylitis Caused by Enterococcus cecorum in Broiler Chickens.
abstract: Enterococcal spondylitis (ES) is a disease of commercial broiler chickens, with a worldwide distribution. Symmetrical hind limb paralysis typical of ES results from infection of the free thoracic vertebra (FTV) by pathogenic strains of Enterococcus cecorum . To determine the pathogenesis of ES, birds with natural and experimental ES were studied over time. In natural disease, case birds (n = 150) from an affected farm and control birds (n = 100) from an unaffected farm were evaluated at weeks 1-6. In control birds, intestinal colonization by E. cecorum began at week 3. In case birds, E. cecorum was detected in intestine and spleen at week 1, followed by infection of the FTV beginning at week 3. E. cecorum isolates recovered from intestine, spleen, and FTV of case birds had matching genotypes, confirming that intestinal colonization with pathogenic strains precedes bacteremia and infection of the FTV. Clinical intestinal disease was not required for E. cecorum bacteremia. In 1- to 3-week-old case birds, pathogenic E. cecorum was observed within osteochondrosis dissecans (OCD) lesions in the FTV. To determine whether OCD of the FTV was a risk factor for ES, 214 birds were orally infected with E. cecorum, and the FTV was evaluated histologically at weeks 1-7. Birds without cartilage clefts of OCD in the FTV did not develop ES; while birds with OCD scores ≥3 were susceptible to lesion development. These findings suggest that intestinal colonization, bacteremia, and OCD of the FTV in early life are crucial to the pathogenesis of ES.
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: L B
authors: LB
authors: Borst
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: M M
authors: MM
authors: Suyemoto
authors: 2 Prestage Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA.
authors: A H
authors: AH
authors: Sarsour
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: M C
authors: MC
authors: Harris
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: M P
authors: MP
authors: Martin
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: J D
authors: JD
authors: Strickland
authors: 2 Prestage Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, USA.
authors: E O
authors: EO
authors: Oviedo
authors: 1 Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors: H J
authors: HJ
authors: Barnes
mesh_terms: D000818:Animals; D002645:Chickens / Q000382:microbiology; D016983:Enterococcus / Q000235:genetics; D016908:Gram-Positive Bacterial Infections / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D007422:Intestines / Q000382:microbiology; D010243:Paralysis / Q000209:etiology / Q000382:microbiology / Q000662:veterinary; D010802:Phylogeny; D011201:Poultry Diseases / Q000209:etiology / Q000382:microbiology* / Q000401:mortality; D013154:Spleen / Q000382:microbiology; D013166:Spondylitis / Q000382:microbiology / Q000662:veterinary*; D013904:Thoracic Vertebrae / Q000382:microbiology
keywords: Enterococcus cecorum; broiler; chickens; enterococcal spondylitis; kinky back; neurologic disease; osteochondritis dissecans; osteochondrosis dissecans; vertebral osteoarthritis