Report of the Department of Agriculture Survey for Antimicrobial Resistance in Bacteria of Animal Origin
The findings of the the Department of Agriculture survey for antimicrobial resistance in bacteria of animal origin support Australia’s rigorous approach to controlling the amounts and types of antibiotics used in our food animal industries. This approach is an important factor in preventing the development and spread of antimicrobial resistance in bacteria. It should reassure public health agencies and consumers about the safety of Australian food of animal origin. The report also provides a baseline for comparison in future surveys.
The study findings are positive for the Australian livestock industries. The results showed that a low proportion of bacteria, isolated from the guts of the three animal species tested were resistant to antibiotics. The National Health and Medical Research Council reviewed the study’s findings and found the impact on human health is likely to be small.
Importantly, this survey found resistance to “critically important” human medicine antibiotics was non existent or low in bacteria isolated from food- producing animals. The World Health Organization defines “critically important” antibiotics as ones where there is potential that their use in humans may be threatened by increased resistance resulting from their non-human use.
All antibiotic use, whether in humans or animals, can result in bacteria that are resistant to antibiotics. In some other countries the use of certain antibiotics in food-producing animals has been linked to human infections with antimicrobial resistant bacteria.The main focus of the survey therefore, was to determine the prevalence of antimicrobial resistant bacteria in the gut of selected food-producing animal species in Australia.
In this survey, samples of gut contents were obtained from healthy animals at 31 abattoirs in Queensland, New South Wales, Victoria and South Australia. Between 200 to 300 samples each from cattle (equal numbers of feedlot, grass-fed and dairy), pigs and poultry were collected between November 2003 and July 2004. Bacteria isolated from the samples were then tested to see if they were resistant to a range of different antibiotics. The bacteria tested were Campylobacter species (poultry only), and Escherichia coli and Enterococcus species (poultry, pigs and cattle).