Survey shows no health implications from antimicrobial resistance

The latest Ministry of Agriculture and Forestry survey has shown no human health implications from antimicrobial resistance in New Zealand food-producing animals and fresh produce.

Antimicrobial-resistant bacteria - which do not respond to antibiotics - are increasingly associated with human illness and death. While the large majority of cases are due to antimicrobial use in human medicine, there is also a potential for transmission via the food chain.

The year-long baseline survey carried out in 2009-2010 focused on antimicrobial resistance to important and commonly used antibiotics among E. coli, Enterococcus, Campylobacter and Salmonella bacteria found in freshly dressed carcasses of calves, pigs and broiler poultry from New Zealand abattoirs and processing plants. It also included samples of Salmonella and E. coli isolated during a survey of fresh produce in 2008-2009.

MAF public health principal advisor Donald Campbell says the survey indicates that our farming community is using antibiotics responsibly in compliance with veterinarian advice, and the little resistance found has no direct implications for human health.

”Although the survey detected some resistance to certain antimicrobials from particular bacteria found in the targeted foods, it is pleasing to see that the resistance has no direct implications for human health,” he says.

Dr Campbell says that comparing results from this survey with the limited data available from earlier New Zealand studies on bacteria isolated from animals suggests there has been no increase in resistance in food-producing animals in New Zealand.

Compared with 2009 data from the Danish DANMAP surveillance system, which uses a similar methodology to that used in this survey, resistance among bacteria from New Zealand pigs and poultry was either lower or not significantly different.

“Denmark is seen as a world leader in controlling antimicrobial resistance, so that’s a good benchmark to measure ourselves against,” Dr Campbell says.

MAF’s baseline survey was carried out to determine the current status and whether there is a need in New Zealand to implement an ongoing surveillance program for antibiotic resistance in food-producing animals.

As part of the management of antibiotic resistance, registrants of restricted veterinary medicines containing antibiotics must provide an annual report of sales by month to MAF. Along with the antimicrobial resistance survey, MAF has released an overview of antibiotic sales and use from 2004-2009. This report shows that total antibiotic sales decreased from a peak of 62,883 kg in 2005/6 to 53,031 kg in 2007/8. Sales increased by 5% between 2007/8 and 2008/9.

A report containing a review and update on New Zealand’s regulatory control of antimicrobial agricultural compounds with regard to antimicrobial resistance has also been released.