Date Published: April 18, 2006
An Australian policy restricting the use of antibiotics in food-producing animals may be linked with the lower levels of drug-resistant bacteria found in its population, scientists now suggest.
Campylobacter jejuni is a leading bacterial cause of food-borne illness in industrialised countries.
Drug resistance can make Campylobacter infections difficult for physicians to treat, and can result in longer bouts of diarrhoea and a higher risk of serious or even fatal illness.
Individuals who showed a bacterial resistance to curative drugs generally were found to be susceptible to inappropriate prescribing or to overuse antibiotics.
An Australian solution to the drug resistance problem has been to prohibit the use of certain antibiotics, called fluoroquinolones, in food animals such as poultry.
The policy assists Australians by protecting its animals and food production levels against the overuse of antibiotics.
To evaluate whether the country’s restrictive antibiotic policy has affected bacterial drug resistance, Australian researchers examined C. jejuni isolates collected from 585 patients in five Australian states.
None of the patients had received fluoroquinolone treatment within the month prior to becoming ill.
The researchers discovered that only two per cent of the locally acquired Campylobacter isolates were resistant to ciprofloxacin, a type of fluoroquinolone.
Countries that allowed fluoroquinolone use in animals may have a drug resistance prevalence of up to 29 per cent.
Ciprofloxacin can be used to treat severe Campylobacter disease, so a low level of bacterial drug resistance should lead to better treatment efficacy.
Lead author Leanne Unicomb, an epidemiologist with OzFoodNet and Australia National University, said: “There are different causes that lead to bacterial antibiotic resistance, and the use of antibiotics in food animals is only one of the multiple causes.
“However, the evidence indicates that use of fluoroquinolones in food animals in other countries has increased the risk of resistance in [Campylobacter] isolates infecting humans,” she added.
The team surmised that the low drug resistance “probably reflected Australia’s policy of prohibiting fluoroquinolones for animal use”.
Other industrialised nations finding benefit in restricting antibiotics in animal food include Sweden, Norway and the US.
The study was published in the 15 May issue of Clinical Infectious Diseases.