Antibiotic resistance is rapidly rising internationally. Many bacterial infections are now very difficult, and sometimes impossible, to treat. Antibiotic resistance is proportional to use. The more antibiotics used, the more resistance develops and spreads.

With many common bacteria infecting people, transmission is almost entirely human-to-human (e.g. pneumococcus). Thus any antibiotic resistance seen in these bacteria, will be almost entirely due to antibiotics used in the human sector. However with some other bacteria, the resistance seen is almost entirely due to what has occurred in the agriculture sector in food animals. Examples are non-typhoid Salmonella and Campylobacter, which in developed countries are almost always acquired via foods. Vegetarians are also at risk because water, food crops and fields (via manure) can be contaminated with resistant bacteria. There are other bacteria where the risk of acquisition from animal sources is more difficult to precisely define, but appears to be quite important. Examples are E. coli and Enterococcus.

Antibiotics have been used for over 60 years as growth promoters in animals. They are also used in large amounts for prophylaxis (called “metaphylaxis” when entire herds are treated at the same time). Huge numbers of animals are treated continuously for most of their life with either in-feed or in-water antibiotics. Some of these “prophylactic” antibiotics are “critically important” classes for humans, such as the fluoroquinolones and 3rd and 4th generation cephalosporins (WHO).

While there is ongoing debate on the exact quantitation of the amount of antibiotic resistant bacteria infecting people coming from food animals, it appears to be large. In Australia fluoroquinolone use is banned in food animals and we have one of the lowest fluoroquinolone resistance rates in campylobacter, salmonella and E.coli.

There is overwhelming evidence around the world that using antibiotics on crops, in aquaculture and in food animals, causes resistant bacteria to develop in large numbers and that these bacteria are transmitted to people via foods and water. When these resistant bacteria infect people they cause increased deaths and morbidity.

Decreasing the total amounts of antimicrobial used in people and agriculture, stopping antibiotics being used as growth promoters, stopping the use of “critically important” antibiotics in food animals, decreasing corruption in countries and improving water quality around the world are all part of a “One Health” approach that if followed will make major contributions to controlling antimicrobial resistance.