Emergence of a tetracycline-resistant Campylobacter jejuni clone associated with outbreaks of ovine abortion in the United States

J Clin Microbiol. 2008 May;46(5):1663-71. doi: 10.1128/JCM.00031-08. Epub 2008 Mar 5.


Campylobacter infection is one of the major causes of ovine abortions worldwide. Historically, Campylobacter fetus subsp. fetus was the major cause of Campylobacter-associated abortion in sheep; however, Campylobacter jejuni is increasingly associated with sheep abortions. We examined the species distribution, genotypes, and antimicrobial susceptibilities of abortion-associated Campylobacter isolates obtained from multiple lambing seasons on different farms in Iowa, Idaho, South Dakota, and California. We found that C. jejuni has replaced C. fetus as the predominant Campylobacter species causing sheep abortion in the United States. Most strikingly, the vast majority (66 of 71) of the C. jejuni isolates associated with sheep abortion belong to a single genetic clone, as determined by pulsed-field gel electrophoresis, multilocus sequence typing, and cmp gene (encoding the major outer membrane protein) sequence typing. The in vitro antimicrobial susceptibilities of these isolates to the antibiotics that are routinely used in food animal production were determined using the agar dilution test. All of the 74 isolates were susceptible to tilmicosin, florfenicol, tulathromycin, and enrofloxacin, and 97% were sensitive to tylosin. However, all were resistant to tetracyclines, the only antibiotics currently approved in the United States for the treatment of Campylobacter abortion in sheep. This finding suggests that feeding tetracycline for the prevention of Campylobacter abortions is ineffective and that other antibiotics should be used for the treatment of sheep abortions in the United States. Together, these results indicate that a single tetracycline-resistant C. jejuni clone has emerged as the major cause of Campylobacter-associated sheep abortion in the United States.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aborted Fetus / pathology
  • Abortion, Veterinary / epidemiology*
  • Abortion, Veterinary / microbiology
  • Amino Acid Sequence
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Typing Techniques / methods
  • Campylobacter Infections / epidemiology
  • Campylobacter Infections / microbiology
  • Campylobacter Infections / veterinary*
  • Campylobacter fetus / classification*
  • Campylobacter fetus / drug effects
  • Campylobacter fetus / isolation & purification
  • Campylobacter jejuni / classification*
  • Campylobacter jejuni / drug effects
  • Campylobacter jejuni / isolation & purification
  • Cluster Analysis
  • DNA Fingerprinting
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Disease Outbreaks*
  • Electrophoresis, Gel, Pulsed-Field
  • Genotype
  • Liver / pathology
  • Lung / pathology
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sheep Diseases / epidemiology*
  • Sheep Diseases / microbiology
  • Tetracycline Resistance*
  • United States / epidemiology


  • Anti-Bacterial Agents
  • Bacterial Outer Membrane Proteins
  • DNA, Bacterial