Antimicrobial Awareness Week 2021: Zoonoses as a driver for antimicrobial resistance

The diseases which are naturally transmitted between humans and animals, are a major driver that can threaten human health by facilitating the emergence of AMR pathogens

By H Rahman, Jagadish B Hiremath
Published: Monday 22 November 2021

Antimicrobials have been among the greatest of human discoveries. They have significantly increased the quality of life and life expectancy for humans and animals.

Intensive livestock farming with the goal of high economic returns employs all means to reduce the level of disease. One such measure is the use of antimicrobials as feed supplements or growth promoters.

In recent years, the use, abuse and misuse of antimicrobials in both, the human and livestock sector, has resulted in large-scale antimicrobial resistance (AMR) among various pathogens and more so, in bacterial pathogens.

Currently, AMR is a global challenge. It has forced international bodies such as World Health Organization, World Organization for Animal Health (OIE) and Food and Agriculture Organization to come together to address the factors responsible for its emergence across the globe.

The emergence and rapid spread of drug-resistant pathogens continue to threaten our ability to treat routine infections which were once treated very effectively. The ineffectiveness of the existing antimicrobials combined with rapid spread of multi- and pan-resistant bacteria is indeed an alarming situation, with an annual 10 million projected deaths by 2050.

Hence, AMR is a major health security issue forcing many countries to adopt regional and national action plans to mitigate the increasing threat of AMR.  

AMR occurs naturally over time, usually through genetic changes which is a part of natural evolution. The resistant organisms are found in people, animals, foods, plants and the environment which can spread between and within the sectors.

AMR, particularly antibacterial resistance (ABR) is frequently reported at the interface of human, animal and environment indicating the role of industry, farming, veterinary practices in ABR in addition to human health practices.

The main drivers of AMR include use, misuse and abuse of antimicrobials. The need for antimicrobials arises when basic requirements like clean water, sanitation and hygiene for animals and humans are not met, leading to frequent infection and disease.

Also, the public health infrastructure to prevent the origin and spread of infections in both, the human and veterinary health sector is poor, leading to more frequent use of antimicrobials to treat the diseases. 

The Global AMR Surveillance System Report in 2019 revealed that the major clinically relevant antibiotic resistant species are:

  • Acinetobacter spp
  • Clostridium difficile
  • Escherichia coli
  • Enterococcus spp
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Staphylococcus aureus
  • Salmonella spp 
  • Shigella spp
  • Streptococcus pneumoniae
  • Neisseria gonorrhoeae

These antibiotic resistant species are prevalent both, in humans and animals with exposure to diverse antimicrobials allowed for use in respective sectors.

Quantitatively, the amount of antimicrobials used in animals is comparable to humans but chances of selection of resistant microbes is high in animals due to larger biomass.

Additionally, the practice of using low doses of antimicrobials as growth promoters in food animals provides a suitable environment for emergence of AMR.

There are multiple studies showing an association between repeated exposure to low levels of antimicrobials and emergence of AMR.

Hence, among the drivers of AMR, zoonoses, the diseases which are naturally transmitted between humans and animals, are a major driver that can threaten human health by facilitating the emergence of AMR pathogens. The spread of antibiotic resistance is also determined by geographical and climatic conditions, policies and socioeconomic status.

National level surveillance and monitoring for emergence and spread of AMR is important for evaluating the effectiveness of local, national and global strategies to mitigate AMR.

H Rahman is Regional Representative for South Asia, International Livestock Research Institute, NASC Complex, DPS Marg, Pusa, New Delhi

Jagadish B Hiremath is Senior Scientist, ICAR – National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru

Views expressed are the authors’ own and don’t necessarily reflect those of Down To Earth

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