Canada reports drop in antibiotic use in humans and food-producing animals

Just as use of antimicrobials in humans can lead to the development and persistence of AMR (Antimicrobial resistance), use of antimicrobials in food-producing and companion animals may also contribute to antimicrobial resistant bacteria. Such bacteria may then be transferred to humans through direct contact with animals, as well as foodborne or waterborne routes.

A new report from the Canadian Antimicrobial Resistance Surveillance System (CARSS) shows rising antibiotic resistance in two major healthcare-associated pathogens, along with noteworthy decreases in antibiotic use in humans and animals. 

Also read, How Fast Food Chains Rate on Reducing Antibiotics in Their Meat Supply.

The CARRS-2017 Report is the third published by the Public Health Agency of Canada (PHAC) and includes surveillance data on antimicrobial resistance and use, both in humans and animals, through 2016. The report is based on available surveillance data from the PHAC's nine surveillance systems and laboratory reference services.

Reductions in animal antibiotic use
The report shows a first-time decline in the amount of medically important antibiotics sold for use in animals. In 2016, the volume of medically important antibiotics distributed for use in food-producing and companion animals in Canada was 1.0 million kilograms—17% lower than in 2015. This decrease was highlighted by a 56% drop in the quantity of fluoroquinolones distributed for use in animals. Of these antibiotics, 99% were used in food-producing animals.

Compared with the 31 European countries that provide data to the European Surveillance of Veterinary Antimicrobial Consumption, Canada ranked fifth-highest in animal antibiotic consumption measured as milligrams of drug per kilogram of animal.

The CARSS-2017 Report also identified several gaps that need to be addressed to improve the depth and the quality of the surveillance data. These include limited data on antibiotic-resistant organisms in the community, non-academic hospitals, and long-term care facilities, and no or limited data on the appropriateness of the antibiotics that are prescribed. In addition, farm-level data on antibiotic use in animals are limited to sentinel farms in swine and poultry.

Reductions in human antibiotic use
The CARSS data also show some encouraging trends in antimicrobial stewardship, particularly in community antibiotic use.

Overall, an estimated 22.6 million antibiotic prescriptions were dispensed in Canada in 2016, with a total expenditure of nearly 700 million Canadian dollars. Analysis of human antibiotic use in the community, which accounted for 92% of all antibiotic prescriptions dispensed in the country, showed that the rate of prescribing dropped from 18.3 defined daily doses (DDDs) per 1,000 inhabitant-days in 2012 to 17.4 DDDs in 2016. Amoxicillin (25% of prescriptions) and azithromycin (10%) were the most frequently prescribed antibiotics in 2016.

Family physicians accounted for 65% of all antibiotic prescriptions dispensed through community pharmacies, most frequently for respiratory infections, genitourinary system infections, and skin and other soft-tissue infections. Data from 2015 showed a downward trend in the antibiotic prescribing rate of physicians and a stable rate for dentists. 

When Canada's community antibiotic consumption in 2015 was compared with 2015 data on outpatient antibiotic consumption in Europe, Canada ranked 13th of 31 countries (ranked from lowest to highest consumption). In 2014, Canada ranked 12th. Europe is considered a good candidate for human antibiotic use comparisons to Canada, because the European Surveillance of Antimicrobial Consumption Network is one of the largest standardized data sources on human antibiotic use and employs methods similar to CARSS's.

The proportion of antibiotic doses in Canada purchased for use in the hospital also remained steady, at around 8%. Of note, however, was an increase in 2016 in hospital purchasing of daptomycin, a last-resort antibiotic generally reserved for life-threatening S aureus and Enterococcus infections.

The PHAC says it will implement a number of initiatives over the next several years to enhance surveillance data in hopes of improving the country's ability to respond to antimicrobial resistance threats.

SOURCE Chris Dall, CIDRAP (Center for Infectious Disease Research and Policy)