Genotype variation and genetic relationship among Escherichia coli from nursery pigs located in different pens in the same farm

BMC Microbiology

Research Article

Matthew Denwood¹  Shahana Ahmed²  Monica Hegstad Hansen²  Ana Herrero-Fresno²  Camilla Zachariasen²  John Elmerdahl Olsen² 

[1] Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark;Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark;

关键词: E. coli;    Swine;    Genetic diversity;    Genetic relationship;    Antimicrobial selection;    REP-PCR;    PFGE;   

DOI  :  10.1186/s12866-016-0912-3

 received in 2016-04-28, accepted in 2016-12-12,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundSo far, little is known about the genetic diversity and relatedness among Escherichia coli (E. coli) populations in the gut of swine. Information on this is required to improve modeling studies on antimicrobial resistance aiming to fight its occurrence and development. This work evaluated the genotype variation of E. coli isolated from swine fecal samples at the single pig and pen level, as well as between pens using repetitive extragenic palindromic (REP) PCR fingerprinting and pulsed field gel electrophoresis (PFGE). The genetic diversity of strains collected from media supplemented with ampicillin or tetracycline was also investigated. Besides, the genetic relationship of strains within each pen, between pens, as well as among strains within each group isolated from media with or without antibiotic, was assessed.ResultsREP-PCR patterns (N = 75) were generated for all the isolates (N = 720). Two profiles (REP_2 and REP_5) dominated, accounting for 23.7 and 23.3% of all isolates, respectively. At the pig and at the pen level, the number of different strains ranged from two to eight, and from 27 to 31, respectively, and multiple isolates from a single pen were found to be identical; however, in some of the pens, additional strains occurred at a lower frequency. E. coli isolates yielding different REP profiles were subjected to PFGE and led to 41 different genotypes which were also compared.ConclusionsDespite the presence of dominant strains, our results suggest a high genetic diversity of E. coli strains exist at the pen level and between pens. Selection with antibiotic seems to not affect the genetic diversity. The dominant REP profiles were the same found in a previous study in Denmark, which highlights that the same predominant strains are circulating in pigs of this country and might represent the archetypal E.coli commensal in pigs.

【 授权许可】

CC BY   
© The Author(s). 2017