Glenda Lewis.
prescribe antibiotics as carefully and appropriately as possible now. We need to save the big guns in the armoury for the bacterial infections that really require this artillery.
Relative to OECD countries, New Zealand is a low user of antimicrobials for farm animals. That is largely because we feed our cattle and sheep grass in wide open spaces. In situations where animals are kept at close quarters and undercover (poultry and pigs), antibiotics are often routinely administered in feed to prevent infection and the rapid spread of disease.
Some dairy farmers give the whole herd antibiotics to prevent mastitis when they stop milking at the beginning of winter. The New Zealand Veterinary Association has set a goal to end prophylactic use of antibiotics in animals by 2030.
Our human/animal use of antibiotics in terms of total weight of active compound is about 50/50, though the farm animal population is many times greater and cattle weigh more than humans and so require more medicine. But it is a concern that there is veterinary use of antibiotics that are vital to treat infections seen in humans.
New Zealand is at the wrong end of the OECD table when it comes to human use of antibiotics. This reflects our high rate of infectious disease, which is increasingly counter to the trend in other countries. This is a concern for reasons other than antimicrobial resistance.
Infections spread more easily in crowded and unhealthy housing conditions, and among people who have poor general health. Doctors have been alarmed by the incidence of rheumatic fever in some areas of the North Island.
The most vulnerable groups are Maori and Pasifika children and people four to 19 years old.
Our reported incidence of campylobacter infection is the second highest in the OECD (more than 6000 cases a year), despite a dramatic reduction of food-borne campylobacter after 2006.
In 2014 a new strain of campylobacter emerged that is resistant to two classes of antibiotic. Up until that point our rates of resistance in campylobacter were extremely low by international standards. We need to continue to drive down infection rates and reverse the emergence of resistant strains.
Animal faecal matter inevitably gets into waterways and can contaminate drinking supplies with pathogens such as campylobacter. Chlorinating drinking water kills pathogens.
Most antibiotics are still effective but taking too many can have adverse side-effects.
Antibiotics kill beneficial as well as harmful bacteria, and reduce the range of bacteria in our guts.
We are only now beginning to understand how important bacteria are to our healthy physical and mental function.
Environmental Science and Research (ESR) reported that the use of broad-spectrum penicillin almost doubled in the period 2006-14.
There is no suggestion that doctors or vets should withhold antibiotics when needed to treat an infection. But the choice of medicine needs to be judicious and carefully considered, and patients need to follow health professionals’ advice.
Scientists have always known that antimicrobial resistance would develop. It is how evolution works. The question is how we can buy time while scientists look for new treatments. ESR notes that there are few prospects in the pipeline.
The ministries of health and primary industries have a fiveyear plan to manage AMR. Part of it is public awareness and active participation.
Our first line of defence is not to get sick in the first place, and not to infect others. Some general advice from our Ministry of Health:
Immunise against infectious diseases
Wash and dry your hands regularly and well Stay at home if you are sick Cover coughs and sneezes Clean surfaces regularly Practise safe sex
One way that antimicrobialresistant organisms move between animals and humans is through the food chain. The NZ Food Safety Science & Research Centre (NZFSSRC) closely watches any food-borne diseases and tracks the spread of resistant organisms, sharing the information with scientists in New Zealand and around the world.
To guard yourself and others against food-borne infection:
Wash and dry your hands before cooking and eating, and teach your children this as well.
Antimicrobial soaps can contribute to the antimicrobial resistance problem, and they are considered no more effective than ordinary soap and water.
Handle raw chicken carefully. Store separately away from other foods. Don’t let the juices splash and wash everything down thoroughly. Cook it until the juices run clear. Likewise any minced meat. Wash fruit and vegetables well. Don’t drink raw milk. It may contain E.coli, listeria, salmonella or campylobacter. Heat it until just boiling (or up to 70 degrees Celsius for one minute) before drinking.
People working with farm animals can be infected by E.coli, listeria, toxoplasma and leptospira. Bugs live on shed floors, animals, pasture, work clothing, and surfaces in the house. There is a noticeable spike in infections at calving time. Wash your hands and leave work clothing outside. Watch the exposure of small children who suffer from these infections more than most. Children are at much higher risk of infection. Healthy animals and people can resist infection. Both need good nutrition, shelter and care.
World Antimicrobial Awareness Week is November 13-19.
Professor Nigel French is the director of NZFSSRC and a professor of food safety and veterinary public health at Massey. Glenda Lewis is a communications adviser to NZFSSRC