title: Occurrence ofPasteurella multocidaamong pigs with respiratory disease in China between 2011 and 2015.
abstract: BACKGROUND
  Prior to the 1990s,P. multocidacapsular serogroup A was the most prevalent in China, followed by serogroups B and D. Thirty years later, serogroup D became the most prevalent, followed by serogroups A and B. However, theP. multocidacapsular serogroups currently circulating in China remain unclear. Therefore, the aim of the present study was to provide an update onP. multocidaserogroups isolated from diagnostic samples collected from clinically diseased pigs in Central and Eastern China from 2011 to 2015.
  
  
  RESULTS
  Between February 2011 and October 2015, 296 isolates ofPasteurella multocidawere collected from 3212 pigs with clinical respiratory disease in 12 provinces of China (isolation rate of 9.2%). Of the 296 collected isolates, 146 (49.3%) wereP. multocidacapsular type A, 141 (47.6%) were capsular type D, and one was capsular type B.Streptococcus suis(94/193; 48.7%),Haemophilus parasuis(76/193; 39.3%),Escherichia coli(53/193; 27.5%), andBordetella bronchiseptica(26/193; 13.5%) were frequently isolated together withP. multocida.A total of 14 toxigenicP. multocidastrains co-isolated with other pathogens from 32 cases of atrophic rhinitis were classified into serogroup D. The virulence ofP. multocidacapsular type A isolates was higher than that of capsular type D isolates based on LD50studies in mice.
  
  
  CONCLUSIONS
  Over the past 5 years,P. multocidacapsular type A was the most frequently isolated from diagnostic submissions in Central and Eastern China, followed by serogroups D and B.
authors.affiliation: Laboratory of Veterinary Microbiology, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.
authors.forename: Huisheng
authors.initials: H
authors.lastname: Liu
authors.affiliation: Laboratory of Veterinary Microbiology, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.
authors.forename: Zhanqin
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Laboratory of Veterinary Microbiology, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Xi
authors.affiliation: Laboratory of Veterinary Microbiology, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Xue
authors.affiliation: Laboratory of Veterinary Microbiology, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China.
authors.forename: Ta
authors.initials: T
authors.lastname: Long
authors.affiliation: Laboratory of Medical Engineering, College of Medical Technology and Engineering, Henan University of Science and Technology, Luoyang, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xue
keywords: Bordetella bronchiseptica; Co-infection; Pasteurella multocida; Respiratory pathogen; Swine