Antimicrobial resistance in livestock and poor quality veterinary medicines

Every year, antimicrobial resistance causes the death of around 700 000 people, and this number is expected to rise to an estimated 10 million deaths annually by 2050.1 Antimicrobial resistance has the potential to affect almost all sustainable development goals (SDGs), particularly those targeting poverty, hunger, health and economic growth. Although the reduction and eradication of antimicrobial resistance is not included as an individual SDG, paragraph 26 of Transforming our world: the 2030 agenda for sustainable development states: “We will equally accelerate the pace of progress made in fighting malaria, [human immunodeficiency virus/acquired immunodeficiency syndrome], tuberculosis, hepatitis, Ebola and other communicable diseases and epidemics, including by addressing growing antimicrobial resistance and the problem of unattended diseases affecting developing countries.”2 There is concern about how antimicrobial resistance emergence in livestock will impact SDG 3, i.e. ensuring healthy lives and promoting wellbeing for all, at all ages.3 With meat production set to increase from 200 million tons to 470 million tons by 2050,4 it is likely that farmers will rely even more on antibiotics to prophylactically prevent disease in their livestock to meet this expected demand. The high proportion of poor-quality veterinary medicine for therapeutic use in livestock compounds the problem of antibiotic overuse, particularly in lowand middle-income countries. The annual market in Africa for substandard and non-registered veterinary medicine is estimated to be 400 million United States dollars,5 equal to that of the officially registered, quality-assured veterinary drug market.6 Numerous cases of antimicrobial resistance in humans have been traced to resistant microbes suspected of originating in livestock,7,8 which is particularly concerning as infected livestock can be asymptomatic.8 Transmission of resistant bacteria from livestock to humans can occur through the consumption of meat, direct contact with colonized animals or manure spread in the environment.7 The strongest correlation between interspecies pathogen transmission is observed in countries with policies to reduce agricultural antibiotic use. When the glycopeptide avoparcin was banned across the European Union in the late 1990s, the prevalence of vanco mycin-resistant enterococci in biological samples from both poultry and humans decreased.9 While research on drug resistance, including the role of poor quality medicine, has increased in recent years, the scientific community has not incorporated the impact of poor-quality veterinary medicine into the overall picture of antimicrobial resistance. Poor-quality medicines that provide subtherapeutic doses of active pharmaceutical ingredient, whether due to inadequate amounts of pharmaceutical, ineffective release, presence of impurities or degradation of compounds, are believed to contribute to antimicrobial resistance by exposing microbes to a level of antibiotic that will not effectively kill the whole microbial population.10 Poor-quality veterinary medicine as a contributor to antimicrobial resistance has been mentioned anecdotally in the literature, but systematic studies are lacking. Given the widespread use of antibiotics in animal husbandry and the persistent problems of drug quality in lowand middle-income countries, this is a significant oversight that could lead to long-term challenges. Increased frequency of antibiotic use in livestock, particularly at subtherapeutic doses due to issues with administration and/ or drug quality, can allow resistant microbes to flourish. While poor-quality veterinary medicine is presumed to impact antimicrobial resistance, there are no robust studies that can act as an evidence base for developing sound policies.