In a recent study published in The Lancet Planetary Health journal, researchers investigated the association between rates of antimicrobial resistance in food-producing animals and humans at country level and environmental, socioeconomic, and anthropogenic indicators.
Study: Global antimicrobial-resistance drivers: an ecological country-level study at the human–animal interface. Image Credit: Fahroni/Shutterstock.com
The growing prevalence of antimicrobial resistance is a significant economic and health burden globally, and statistics from 2019 indicate that close to 1.27 million deaths were attributed to infections from antimicrobial-resistant bacteria.
Although antimicrobial resistance in bacteria can occur naturally through novel mutations or horizontal gene transfer of antimicrobial-resistant phenotypes between bacteria, the uncontrolled use of antimicrobials can drive the selection of antimicrobial-resistant phenotypes.
Furthermore, indiscriminate antimicrobial usage is not restricted to human consumption practices. The growing demand for meat and animal products has resulted in a substantial increase in antibiotic use on food-producing animals worldwide, especially in countries belonging to the low- and middle-income groups.
Apart from the unnecessary use of antibiotics to treat viral infections, underlying health conditions such as smoking behavior, alcoholism, and obesity also increase the predisposition to infections and increase the probability of antimicrobial resistance by reducing the efficacy of treatments.
Environmental and socioeconomic factors, including the hygiene and sanitation infrastructure, climate, and the gross domestic product (GDP) per capita, are also associated with the risk of antimicrobial resistance emergence.
About the study
In the present study, the researchers used country-level data until 2018 to determine associations between global antimicrobial resistance rates and environmental, sociodemographic, and health-related variables.
The dependent variables included in the study comprised antimicrobial resistance rates for humans and food-producing animals. Additionally, a sub-analysis consisting of specific antibiotic-resistant bacteria was also conducted.
These included Acinetobacter baumanii and Pseudomonas aeruginosa, resistant to carbapenem, Escherichia coli and Klebsiella pneumoniae, resistant to third-generation cephalosporins, Staphylococcus aureus resistant to oxacillin, and Enterococcus faecium resistant to vancomycin in humans.
The antimicrobial resistance rates for humans were obtained from the Pan American Health Organisation (PAHO) and the Global Antimicrobial Resistance and Surveillance System (GLASS) by the World Health Organization (WHO), while those for food-producing animals were obtained from ResistanceBank and European Food Safety Authority (EFSA).
The data for humans spanned the years between 1998 and 2017, while those for the food-producing animals were available from 2000–2015.
The results identified that antimicrobial consumption in humans and food-producing animals was significantly associated with increasing antimicrobial resistance rates.
Furthermore, the development of antimicrobial resistance in critical human pathogens was also linked to antimicrobial consumption in food-producing animals and vice-versa, indicating bidirectional associations.
The sub-analyses with specific pairs of antibiotics and bacteria indicated that the drug-pathogen pairs that had the highest odds of resistance were P. aeruginosa and carbapenem, and A. baumanii and carbapenem, although the use of cephalosporins in association with these two bacteria also showed increased odds of resistance.
Various socioeconomic factors, such as the GINI index, which measures the distribution of income across the population of a country, as well as sanitary and hygiene conditions, were found to be positively associated with human antimicrobial resistance rates, while factors such as the prescription and sales of antibiotics and the GDP were negatively associated with antimicrobial resistance rates.
Additionally, governance indicators such as quality of regulation, the rule of law, corruption control, accountability, and voice were associated with antimicrobial resistance in animal pathogens and medium, high, and critical WHO-priority human pathogens.
The results suggested that indiscriminate consumption of antibiotics was a secondary factor in determining the risk of antimicrobial resistance, and socioeconomic factors played a more significant role in the increasing antimicrobial resistance in human and food-producing animal pathogens.
The authors believe that reducing or preventing the spread of antimicrobial resistance will require action plans at national levels that go beyond regulating the misuse of antibiotic prescriptions.
Furthermore, the bidirectional associations between antimicrobial resistance in human and animal pathogens indicated that implementing integrated control measures is necessary.
Overall, the results indicated that while antimicrobial consumption in humans and food-producing animals are independently and bi-directionally associated with developing antimicrobial resistance in human and animal pathogens, socioeconomic factors significantly increase the risk factors.
Therefore, measures to limit the spread of antimicrobial resistance must go beyond restricting the indiscriminate use of antibiotics and address the socioeconomic disparities at a national level.