title: Diversity of Escherichia coli strains involved in vertebral osteomyelitis and arthritis in broilers in Brazil.
abstract: BACKGROUND
  Locomotor disorders and infections by Escherichia coli represent major concerns to the poultry industry worldwide. Avian pathogenic E. coli (APEC) is associated with extraintestinal infections leading to respiratory or systemic disease known as colibacillosis. The most common lesions seen in cases of colibacillosis are perihepatitis, airsacculitis, pericarditis, peritonitis/salpingitis and arthritis. These diseases are responsible for significant economic losses in the poultry industry worldwide. E. coli has been recently isolated from vertebral osteomyelitis cases in Brazil and there are no data on molecular and phenotypic characteristics of E. coli strains isolated from lesions in the locomotor system of broilers. This raised the question whether specific E. coli strains could be responsible for bone lesions in broilers. The aim of this study was to assess these characteristics of E. coli strains isolated from broilers presenting vertebral osteomyelitis and arthritis in Brazil.
  
  
  RESULTS
  Fifteen E. coli strains from bone lesions were submitted to APEC diagnosis and setting of ECOR phylogenic group, O serogroup, flagella type, virulence genes content, genetic patterns by Pulsed Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST). In addition, bacterial isolates were further characterized through a lethality test, serum resistance test and antibiotic resistance profile. E. coli strains harbored different genetic pattern as assessed by PFGE, regardless of flock origin and lesion site. The strains belonged to seven sequence types (STs) previously described (ST117, ST101, ST131, ST 371 and ST3107) or newly described in this study (ST5766 and ST5856). ECOR group D (66.7 %) was the most frequently detected. The strains belonged to diverse serogroups (O88, O25, O12, and O45), some of worldwide importance. The antibiotic resistance profile confirmed strains' diversity and revealed a high proportion of multidrug-resistant strains (73 %), mainly to quinolones and beta-lactams, including third generation cephalosporin. The percentage of resistance to tetracycline was moderate (33 %) but always associated with multidrug resistance.
  
  
  CONCLUSIONS
  Our results demonstrated that vertebral osteomyelitis and arthritis in broilers can be associated with highly diverse E. coli based on molecular and phenotypic characteristics. There was no specific virulence patterns of the E. coli strains associated with vertebral osteomyelitis or arthritis. Also, E. coli strains were frequently multidrug resistant and belonged to STs commonly shared by APEC and human ExPEC strains.
authors.affiliation: Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinárias, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Campus Pampulha, 30161-970, Minas Gerais, Brazil.|ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France.
authors.forename: Juliana Fortes Vilarinho
authors.initials: JFV
authors.lastname: Braga
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France.
authors.forename: Nathalie Katy
authors.initials: NK
authors.lastname: Chanteloup
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France.
authors.forename: Angélina
authors.initials: A
authors.lastname: Trotereau
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Baucheron
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Guabiraba
authors.affiliation: Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinárias, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Campus Pampulha, 30161-970, Minas Gerais, Brazil.
authors.forename: Roselene
authors.initials: R
authors.lastname: Ecco
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, 37380, Nouzilly, France. catherine.schouler@tours.inra.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Schouler
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001168:Arthritis / Q000382:microbiology / Q000662:veterinary*; D001938:Brazil; D002645:Chickens; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics; D014644:Genetic Variation; D010019:Osteomyelitis / Q000382:microbiology / Q000662:veterinary*; D011201:Poultry Diseases / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D037521:Virulence Factors
keywords: APEC; Bacterial infections; Broilers; Multidrug-resistant E. coli; Pathology; Virulence genes