title: Isolation, identification, and pathogenicity of O142 avian pathogenic Escherichia coli causing black proventriculus and septicemia in broiler breeders.
abstract: Avian colibacillosis, characterized by black proventriculus and caused by avian pathogenic Escherichia coli (APEC) with an uncommon O142 serogroup, was diagnosed in young broiler breeders. Colonization and persistence assays performed in 7-day-old broilers showed that the bacterial load of the APEC 4d/9-1 O142 proventricular isolate in the lung was about 10-fold higher than that of the APEC 4d/9-1 O142 heart blood isolate (P<0.01), and about 100-fold higher in the heart blood, livers, spleens, kidneys, and proventriculi of inoculated broilers (P<0.001). When 32 common virulence genes of APEC were tested, the two isolates had nearly identical profiles, except that only the APEC 4d/9-1 O142 proventricular isolate carried the feoB gene. Furthermore, 100% mortality was observed in both 1-day-old Arbor Acres (AA) broilers and 1-day-old specific-pathogen-free (SPF) chickens inoculated with 10(6) colony-forming units of the APEC 4d/9-1 O142 proventricular isolate. However, black proventriculus was only observed in the dead AA broilers, consistent with the clinical occurrence of the disease. This implies that the black proventriculi seen in the dead birds, caused by the APEC 4d/9-1 O142 proventricular isolate, was breed-specific. Both the APEC 4d/9-1 O142 proventricular and heart blood isolates belong to phylogroup B2. However, the former was assigned to ST131 and the latter to ST2704 with multilocus sequence typing, demonstrating the genetic heterogeneity of these two bacterial isolates, although they were derived from the same dead broiler. These results suggest that the O142 APEC isolate was the main pathogenic agent for black proventriculi in 7-day-old broiler breeders.
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Wang
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Chunguang
authors.initials: C
authors.lastname: Cao
authors.affiliation: Huaiyin Normal University School of Life Science, 223001, China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Huan
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Liuli
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Mu
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Xianglei
authors.initials: X
authors.lastname: Dong
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China. Electronic address: gsong@yzu.edu.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.affiliation: Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou/College of Veterinary Medicine, Yangzhou University, 225009, China.
authors.forename: Xiufan
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D002645:Chickens / Q000382:microbiology*; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks / Q000662:veterinary; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology*; D011531:Proventriculus / Q000382:microbiology*; D018805:Sepsis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013272:Stomach Diseases / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*
keywords: Avian pathogenic Escherichia coli; Black proventriculus; Heart blood isolate; Proventricular isolate; Virulence