Use of antimicrobials in farming has enabled the growth of intensive animal production and helped in meeting the global increase in demand for animal protein. However, the widespread use of veterinary antimicrobials drives antimicrobial resistance, with important consequences for animal health, and potentially human health. Global monitoring of antimicrobial use is essential: first, to track progress in reducing the reliance of farming on antimicrobials. Second, to identify countries where antimicrobial-stewardship efforts should be targeted to curb antimicrobial resistance. Data on usage of antimicrobials in food animals were collected from 42 countries. Multivariate regression models were used in combination with projections of animal counts for cattle, sheep, chicken, and pigs from the Food and Agriculture Organization to estimate global antimicrobial usage of veterinary antimicrobials in 2020 and 2030. Maps of animal densities were used to identify geographic hotspots of antimicrobial use. In each country, estimates of antimicrobial use (tonnes) were calibrated to match continental-level reports of antimicrobial use intensity (milligrams per kilogram of animal) from the World Organization for Animal Health, as well as country-level reports of antimicrobial use from countries that made this information publicly available. Globally, antimicrobial usage was estimated at 99,502 tonnes (95% CI 68,535–198,052) in 2020 and is projected, based on current trends, to increase by 8.0% to 107,472 tonnes (95% CI: 75,927–202,661) by 2030. Hotspots of antimicrobial use were overwhelmingly in Asia (67%), while <1% were in Africa. Findings indicate higher global antimicrobial usage in 2030 compared to prior projections that used data from 2017; this is likely associated with an upward revision of antimicrobial use in Asia/Oceania (~6,000 tonnes) and the Americas (~4,000 tonnes). National-level reporting of antimicrobial use should be encouraged to better evaluate the impact of national policies on antimicrobial use levels.

Antimicrobial resistance (AMR) is a growing threat to human and animal health. However, in aquatic animals—the fastest growing food animal sector globally—AMR trends are seldom documented, particularly in Asia, which contributes two-thirds of global food fish production. Here, we present a systematic review and meta-analysis of 749 point prevalence surveys reporting antibiotic-resistant bacteria from aquatic food animals in Asia, extracted from 343 articles published in 2000–2019. We find concerning levels of resistance to medically important antimicrobials in foodborne pathogens. In aquaculture, the percentage of antimicrobial compounds per survey with resistance exceeding 50% (P50) plateaued at 33% [95% confidence interval (CI) 28 to 37%] between 2000 and 2018. In fisheries, P50 decreased from 52% [95% CI 39 to 65%] to 22% [95% CI 14 to 30%]. We map AMR at 10-kilometer resolution, finding resistance hotspots along Asia’s major river systems and coastal waters of China and India. Regions benefitting most from future surveillance efforts are eastern China and India. Scaling up surveillance to strengthen epidemiological evidence on AMR and inform aquaculture and fisheries interventions is needed to mitigate the impact of AMR globally.

ntimicrobials are used in agriculture as disease treatments, prophylactically to prevent infections in healthy animals and to increase productivity 1 . However, the routine use of antimicrobials as surrogates for good hygiene practices on farms 2,3 is driving a rise in antimicrobial resistance (AMR), with increasingly serious consequences for animal health 1,4 and potentially for human health 5,6 .Globally, 73% of antimicrobials are used in animals 7 , with China being the largest consumer of antimicrobials in absolute terms (41,967 t in 2017) and the second largest consumer in relative terms with 200 mg kg −1 (ref. 8 ) (Supplementary Fig. 1a,b). In comparison, Denmark and the Netherlands use respectively 39 and 56 mg kg −1 (ref. 9 ), while maintaining a productive livestock sector. Multiple factors may contribute to antimicrobial overuse in China. Meat production has grown by 560% since 1979 (FAOSTAT, http://www. fao.org/faostat/en/#data/QL), which could have made farmers reliant on antimicrobials to prevent infections. Veterinary antimicrobials are reportedly accessible without prescriptions 10 and are sold at low prices in comparison to other countries 11 . As in many other low-and middle-income countries (LMICs) 12,13 , farmers predominantly obtain antimicrobials from local drug stores where vendors also provide medical advice without veterinary training 10,14 . Additionally, enforcing the existing regulations 10 on the compounds authorized in animals, or the recently announced ban on growth promoters 15 , remains a formidable challenge in a country where 360 million people are active in agriculture (World Bank, https:// data.worldbank.org/indicator/SL.AGR.EMPL.ZS). In the last 5 yr, China has reported multiple first emergence of resistance genes to last-resort antimicrobials such as colistin and tigecycline 16,17 and a recent global analysis suggested that China may have become one of the largest hotspots of resistance among LMICs 4 , ranking eighth in relative terms, and first in absolute terms, for the animal-associated burden of AMR amongst LMICs (Supplementary Fig. 1d,e).