Changing animal antibiotic regulations

Non-typhoidal Salmonella and Campylobacter are the top two causes of human bacterial gastroenteritis, generally arising from the consumption of infected meat and poultry. Chronic and invasive infections by these species in people are usually treated with antibiotics, therefore antibiotic resistance arising from the use of antibiotics in food producing animals is a valid concern.

The research led by Professor Laura Piddock over a period from 1987 to 2009 investigated how exposure of bacterial species to fluoroquinolone antibiotics resulted in the emergence of antibiotic resistant strains. Resistance was demonstrated in laboratory studies and then in the large scale sampling of commercial flocks of chickens and pigs pre, during and post therapeutic application of fluoroquinolone antibiotics. The work documented a rapid emergence of resistant strains in the animals, which were then passed on through the food chain.

The research provided a scientific and mechanistic insight into the consequence of use of fluoroquinolone antibiotics in animals reared for food production, particularly poultry, and selection of fluoroquinolone resistant mutants.

The work showed how likely resistance was to emerge, the conditions under which resistance can be selected and the genetic mechanisms of this resistance as well as demonstration for both Salmonella and Campylobacter that the same mechanisms seen in animal isolates are common in human isolates.

These seminal studies provided unequivocal evidence of the selection of antibiotic resistant bacteria in animals reared for food production and which were present at slaughter and entry to the food chain.

The outcomes of this research have supported policy makers to formulate opinions as to the safe use of antibiotics in food producing animals and have been used extensively by the FDA in their decision to ban the fluoroquinolone antibiotics enrofloxacin and sarafloxacin use in food producing animals in the USA in September 2005. This has impacted substantially on the use of antibiotics in food-producing animals and the presence of antibiotic resistant strains in the food chain since this date.

In the UK, the Veterinary Medicines Directive (VMD) increased awareness of the impact of the use of fluoroquinolone antibiotics in animals, and this has led to a reduction of the amount used by veterinarians. The European Medicines Agency is again reviewing the EU policy on antibiotics used veterinary medicine on a case by case basis and the use of fluoroquinolone antibiotics in animals reared for food production has once again come under close scrutiny.

Professor Laura Piddock has also used her international profile in the field of antimicrobial resistance to launch the ‘Antibiotic Action’ campaign – a global initiative designed to inform and educate all about the need for discovery, research and development of new antibiotics as well as appropriate use.

If this has sparked an interest in studying a course in the College of Medicine and Health, you can find a list of the of Undergraduate, Postgraduate and Doctoral research opportunities on offer from the College:

• Undergraduate
• Postgraduate
• Doctoral research

You can also read some of the publications resulting from the research:

Gaunt PN, Piddock LJ. Ciprofloxacin resistant Campylobacter spp. in humans: an epidemiological and laboratory study. J Antimicrob Chemother. 1996; 37:747–57.

2. Piddock, L.J.V., Ricci, V., Pumbwe, L, Everett, M.J. & Griggs, D.J. (2003) Fluoroquinolone Resistance in Campylobacter species from Man and Animals: detection of mutations in Topoisomerase Genes Journal of Antimicrobial Chemotherapy 51: 19-26. PMID: 12493783