Antibiotics and resistance
Some bacteria are developing resistance to antibiotics. It's important to use antibiotics responsibly to help prevent resistant bacteria developing. Learn about antibiotic resistance and how MPI controls antibiotic use on New Zealand animals.
Antibiotics are used to fight infections in humans and animals because they kill bacteria or prevent it growing. Some bacterial strains have evolved, either by natural mutation or by exposure to specific chemicals or antibiotics, so they are no longer killed when exposed to certain antibiotics. This means:
- some diseases are on the rise – such as human tuberculosis
- antibiotic resistant bacteria now occur in hospitals – such as methicillin–resistant Staphylococcus aureus (MRSA).
Monitoring antibiotic resistance
Limited overseas evidence indicates that in some cases antibiotic use in animals may contribute to antibiotic resistance in humans. Since 1972, the Ministry of Health has monitored antibiotic resistance for the main disease-causing microorganisms.
There is no evidence so far that in-feed antibiotics have led to resistance. Compared to many other countries, New Zealand has relatively low levels of antimicrobial resistance. Despite this, evidence of such trends is continually monitored and, if evidence shows a link, controls on antibiotic use in animals will be changed.
One of the main monitoring programmes MPI has in place monitors sales of agricultural compounds containing antibiotics, used in both horticulture and veterinary medicine. The sales trends for these products are monitored to ensure the regulatory controls on antibiotics are effective and that any significant or concerning changes can be investigated.
Find out more
- Antimicrobial resistance – Ministry of Health website
- Global antimicrobial resistance – World Health Organization website
Antibiotic use in animals
Like humans, animals sometimes need antibiotics to fight off bacterial infections.
Most antibiotics can only be used to:
- treat individual animals or groups of animals that show symptoms of disease. Most antibiotics are used for this purpose
- prevent sickness in cases where there's a high risk to the animal – for example, when some animals in the group are already showing signs of disease.
Overseas, healthy animals may be given very low antibiotic doses over long periods to increase growth.
Controls on antibiotic use in food animals
Any use of antibiotics in animals is regulated under legislation, including the Animal Compounds and Veterinary Medicines Act.
Animals treated with antibiotics can't be slaughtered for a set time (withholding period) after treatment. This ensures the medicine has had time to work and pass out of the animal's system. The level of antibiotic that remains in the animal, must not exceed the maximum residue level (MRL).
Complying with the MRL ensures any residues left in foods are at safe levels. It also ensures the remaining antibiotic level is too low to contribute to antibiotic resistance.
Animal welfare and human health come first
New Zealand is dependent on our reputation as a producer of safe food so protecting our animal welfare and human health are priorities.
All antibiotics registered for use in animals in New Zealand are assessed against thorough review criteria before being approved. They are reviewed for veterinary use and human health significance as agreed with the Ministry of Health. MPI must also be satisfied that use of the antibiotic won't leave unsafe residues in food.
Antibiotics that could create resistance problems in humans are restricted by MPI and need a veterinary prescription before sale or use.
Who to contact
If you have questions about antibiotic resistance, email firstname.lastname@example.org.