Poster Presentation MedVetPATHOGENS 2018

Multi-drug resistant bacterial isolates from the interdigital skin of the ovine hoof (#102)

Hayley J Marshall 1 , Katie Kelly 1 , Diana Vargas Galloa 1 , Lis King 2 , Fiona Lovatt 1 , Adam Blanchard 1 , Peers Davies 3 , Sabine Tötemeyer 1
  1. University of Nottingham , Nottingham
  2. AHDB, Kenilworth, Warwickshire
  3. University of Liverpool, Liverpool

Background: The overuse of antibiotics in both human and animal medicine has intensified selective pressure on bacteria, promoting multiple mechanisms of resistance, spreading rapidly through horizontal gene transfer. Antimicrobial resistant bacteria transferred from animals to humans impact on future food security and human health. The UK sheep industry represents the largest in Europe and tetracycline is the most common antibiotic used to treat infectious diseases such as footrot. Farmers and veterinarians are under increasing pressure to reduce antibiotic use.

Hypothesis: In this context, we hypothesised that bacteria carried on the interdigital skin of sheep would carry resistance to the commonly used antibiotic tetracycline as well as to other antibiotics.

Methods: To test this, E. coli isolated in the presence and absence of tetracycline from ovine interdigital skin swabs were tested by disk diffusion assays for their sensitivities to a range of other antibiotics used in the sheep industry. In addition, sensitivity to antibiotics classed as both critically important (fluoroquinolone & carbapenem) and highly important (2nd generation cephalosporin) to human health based on the WHO (World Health Organisation) classification were also tested. 

Results: 98% of tetracycline resistant isolates from the ovine interdigital skin were multi-drug resistant due to their resistance to the three antibiotic classes tetracycline, aminoglycosides (Spectinomycin, Streptomycin) and sulphonamide (Sulphatriad). The isolates were sensitive to antibiotics of critical and high importance to human health.

Conclusion: Although isolates found on the ovine interdigital skin were not resistant to antibiotics important to human health, they are multi-drug resistant to antibiotics used in the sheep industry. In particular, resistance to spectinomycin is of concern as it is used to treat neonatal lambs with colibacillosis (watery mouth). This study highlights the importance of responsible use of antibiotics to slow the spread of resistance and to maintain effective treatment.