Understanding Antimicrobial Resistance: From Farm to Plate

Antimicrobial resistance (AMR) is defined as the development in microorganisms such as bacteria, fungi, viruses, and some parasites of traits that prevent antimicrobials from working against these microorganisms. Antimicrobial resistance occurs naturally. However, (mis)use and overuse of antimicrobials in humans as well as in animals has been shown to accelerate the selection and emergence of resistant microorganisms. Antimicrobial resistance is currently considered one of the major threat to global health and food security. Antimicrobials are routinely used for prevention and treatment of disease in animals and they have become a part of food production animals to such an extent where nearly all feed for growing animal is supplemented with antimicrobials either at subtherapeutic or therapeutic concentrations.

It is estimated that the volumes of antimicrobials used in food animals exceeds the use in humans worldwide, and nearly all the classes of antimicrobials that are used for humans are also being used in food animals, including the newest classes of drugs such as third- and fourth-generation cephalosporins, fluoroquinolones, glycopeptides, and streptogramins (Aarestrup et al., 2008).

REASONS /MAJOR CAUSES OF AMR DEVELOPMENT IN ANIMALS THAT CONTRIBUTES SPREAD TO HUMANS

1.LACK OF KNOWLEDGE ABOUT ANTIBIOTICS AMONG FARMERS.

Lack of awareness among farmers in various regions of India about the about antibiotic usage and the concept of antimicrobial resistance. According to a study conducted in Krishnagiri and Kollar district of Karnataka state ,a higher percentage of 88% farmers were unaware of antibiotic usage either on their animals or antibiotic residues in milk.

2.PURCHASE OF OVER THE COUNTER ANTIBIOTICS

The sale of antibiotic to farmers is largely unregulated in India and drugs are easily available without a valid prescription or with old ones.overuse, self medication, incorrect drug usage , inappropriate doses and stopping treatment as soon as symptoms improve leads to antimicrobial resistance.

3 . WITHDRAWAL PERIOD

Withdrawal period of antimicrobials refers to the interval between the last dose of antimicrobial administered to the animal and the interval in which the residue level in the tissues (muscle, liver, kidney, skin/fat) or products (milk, eggs, and meat) is less than or equal to the Maximum Residue Limit (MRL). Most of the dairy and poultry farmers are unaware of the withdrawal period of antimicrobial and they kept selling meat,milk and poultry products during and after the use of antibiotics that leads to development of amr .

In addition to the factors discussed above, several other practices also play a significant role in the emergence and spread of antimicrobial resistance
•Lack of laboratory diagnosis before antibiotic use
•Use of antibiotics as growth promoters (where still practiced)
•Poor awareness of antimicrobial stewardship among farmers and animal health workers etc.

In the mid-1990s the detection of vancomycin-resistant Enterococcus f aecium as well as quinolone-resistant Salmonella and Campylobacter in food animals and evidence of their spread to humans elevated the scientific and public concerns to new levels. This prompted a series of international expert consultations and meetings under the auspices of the WHO and/or the OIE, and it also led to implementation of specific interventions to contain antimicrobial resistance in the food-production chain in many countries, most importantly the complete termination of the use of antimicrobial growth promoters in Europe (FAO et al., 2004; WHO, 1997).

Recently a number of antimicrobial-resistant pathogens have emerged in the food-production chain: extended beta-lactamase producing Salmonella and Escherichia coli, transmissible quinolone resistance (qnr) in Salmonella and E. coli and animal-associated methicillin-resistant Staphylococcus aureus (MRSA), which can transmit to, and cause infections in, humans. These emergences can all be associated with the use of antimicrobial agents in food animals, and they have led to renewed attention to the use of certain types of antimicrobials in food animals that are considered critically important for human health (Aarestrup et al., 2008; Xia et al., 2010).

How AMR from Animals is Transferred to Humans?

Amr is serious threat to international public health as it impairs the potency and efficacy of antibiotics as well as other antimicrobial drugs.Livestock production employs antibiotics at an excessive level to enhance growth and prevent sickness in the animals. Such an approach may promote the dissemination of antimicrobial-resistant bacteria within animal populations. These resistant bacteria can subsequently penetrate the environment via multiple pathways, including manure and runoff, eventually reaching the human population.
There are three major sources of resistance in the cultivation of farm animals. These include commensals, soils, and the farm animals themselves.

1. Commensals

Commensals are microorganisms that normally live in the body without harming and often have a mutualistic association with the host. Such organisms are part of the normal flora, for example, bacteria residing in the gut, skin,
or mucous membranes. Commensal bacteria may host and share antimicrobial resistance genes. These are capable of being passed to pathogenic bacteria, widening the pool of
resistant pathogens that may produce infections. Several of these bacteria have been shown through research to contain homologues of resistance genes from associated pathogenic bacteria. Whether or not gene flow from commensals to the pathogen happens is still questionable.

2. Soil

There exists a common resistome among the soil bacteria and pathogenic humans that indicates that the soil microbiota is a reservoir of resistance genes. Horizontal gene transfer can enable this exchange; these systems provide mechanisms whereby the bacteria transfer genes, including antibiotic resistance genes. ARGs allow transmission between and
within species. It drives the evolution of mobile genetic elements, e.g., plasmids carrying multiple antibiotic resistance genes, leading to multidrug resistance and ubiquitous drug-resistant bacteria; these plasmids can be transferred between a variety of species of bacteria within various environments.

3. Farm animals

Industrial production of livestock heavily relies on its usage of antimicrobial agents to improve animal health and yield. They are mainly used for i) growth promotion, ii) disease prevention, iii) lack of regulation in antibiotic use, and iv) low cost and easy access. Farm workers and veterinarians who are in direct contact with livestock can be exposed to a large amount of bacteria that are present in the environment around the animals (e.g., water, soil, feed). Transmission of the microbes such as Escherichia coli, Salmonella, and Campylobacter can occur through open wounds, respiratory tract, and hand-to-mucosal zone contact. A study conducted in 2021 -23 identified the genetic relatedness of multidrug-resistant E. coli, which were isolated from humans and poultry environments. Among the 110 strains, 42.7% were sourced from humans, 37.7% from hens, and 24.5% were derived from the poultry environment. Antibiotics that were
significantly suppressed were tetracycline, streptomycin, ampicillin, and gentamicin. These findings evaluate the widespread prevalence of MDR E. coli in humans who are working in poultry environments. This suggests strong proof
for the dangers faced by farmers through the transmission from the poultry produce, chickens, and their surroundings.

NATIONAL STRATEGY FOR AMR CONTAINMENT FOR NAP AMR 2.0 (2025-29)

The National Strategy for AMR Containment defines the goal of AMR Containment in India and defines the six strategic objectives to achieve that goal. Each strategic objective outlines sub-objectives which further include key activities. This framework developed in consultation with all key stakeholders has guided the development of action plans by each stakeholder ministry and department.

Vision

Create a sustainable ecosystem for humans, animals, plants and environment by preventing emergence and transmission of AMR through effective sectoral and Multisectoral evidence-based ‘One Health’ approach.

Goal

Protect the health of humans, animals, plants and environment through improving awareness and education, strengthening laboratory capacity for AMR detection, prevention of infections, uninterrupted access to and appropriate use of antimicrobials, effective research and innovation and coordination and collaboration.

The above vision and goal shall be achieved through the following guiding principles:

● “Whole of government” approach with sustained funding within each sector/department
● Effective sectoral action to be the foundation of Intersectoral coordination, with identification of
activities where cooperation, coordination & collaboration with other sectors is required
● Overarching Multisectoral coordination between various stakeholders
● Framework of six strategic objectives with sub-objectives and activities to guide development of action plan by key stakeholder departments
● After NAP AMR 2.0 is launched, each department will develop an operational plan towards implementation of the action plan ensuring engagement of private sector, technical institutions, professional groups, industry, cooperatives, NGOs, international partners and other relevant organisations
● Leveraging existing national expertise, infrastructure and resources for complementarity to avoid duplication and ensure cost-effectiveness
● Develop a common platform for capturing status of AMR containment activities in real time
● Contribution to global efforts in containing AMR through international collaborations
● Measuring outcome through simple and effective key performance indicators