COMBATING AMR: STRATEGIES IN INDIAN LIVESTOCK & POULTRY
Veera Lakshmi M *, Mohanambal K1, Sumathi D1 and Sasikala K1
*Final BVSc & AH student, Department of Veterinary Clinical Medicine,
Veterinary College and Research Institute, Namakkal – 637 002
Tamil Nadu Veterinary and Animal Sciences University, Chennai – 600 051
ABSTRACT
Antimicrobial resistance has rapidly evolved into a global health emergency, affecting humans, animals and ecosystems. Antimicrobials such as antibiotics were once a boon to humankind and animals by saving millions of lives through controlling deadly bacterial infections. However, overuse and misuse of these drugs such as unnecessary prescriptions, incomplete courses and routine use in livestock feed have led to the emergence of Antimicrobial Resistance (AMR). Now, many disease-causing microbes have become resistant to even the most powerful antibiotics, turning this boon into a bane. This article is regarding the antimicrobial resistance in animals, which contributes global threats to both humans and animals. It reviews on antimicrobial resistance in poultry and dairy cattle and its residues on food products which causes impact on humans. Strategies to combat antimicrobial resistance in livestock were discussed briefly including managemental, therapeutic practices, alternatives to antimicrobials, regulatory policies and education and creating awareness. This article concludes the requirement of one health approach, for focusing on rational drug use, strict policy enforcement, farmer education and continuous surveillance for combating AMR in Indian livestock and poultry sector.
INTRODUCTION
Antimicrobial resistance refers to the ability of microorganisms that endure the effects of antimicrobial agents, resulting in treatment failure and prolonged illness (Singh et al.,2025). Resistant pathogens have emerged as a global concern with 4.95 million deaths linked to bacterial AMR in 2019 alone (Wang et al.,2024). The dissemination of resistance across countries and species is driven by factors such as global trade, transportation and indiscriminate antimicrobial usage (McEwen et al.,2002). AMR not only affects clinical outcomes, but also influences food production systems, economic stability and community welfare, making it a cross- sectoral challenge that requires coordinated intervention (Hazards et al.,2021).
MECHANISMS OF ANTIMICROBIAL RESISTANCE
Microbes develop resistance through several biochemical and genetic strategies. These include enzymatic degradation of drugs, alterations in target sites, decreased membrane permeability, activation of efflux pumps, drug sequestration, adoption of alternative metabolic pathways, and formation of biofilms that offer protective barriers (Gonzalez Zorn et al.,2012). Excessive and irrational use of antimicrobials in human and veterinary medicine accelerates these mechanisms by exerting selective pressure on bacterial populations (McEwen et al.,2002).
DRIVING FACTORS FOR ANTIMICROBIAL RESISTANCE
One of the most influential drivers of AMR in animals is the use of antimicrobials in feed and water as growth promoters, which allows both commensal and pathogenic bacteria to develop resistance, ultimately threatening food safety and public health (Mdegela et al., 2021). Other contributors of AMR in animals include the misuse of antibiotics in farm animals (Baynes et al.,2016), inappropriate therapeutic use, metaphylactic and prophylactic applications and inadequate adherence to withdrawal periods (Kim et al., 2019). The factor worsening the problem is the limited awareness and knowledge among livestock farmers regarding antimicrobial stewardship and responsible antibiotic use (Rees et al., 2019).
ANTIMICROBIAL RESISTANCE IN POULTRY
The antimicrobials used in poultry production are easily transmitted to humans through food products. Hence, antimicrobial resistance in the poultry sector is a major public health concern. A survey conducted in India reported that more E. coli isolates were multidrug-resistant in poultry than in other livestock species. Factors responsible include irrational use of antibiotics for disease control, improper use of growth promoters and routine flock management. Furthermore, poultry manure containing antibiotic residues enters the environment, contributing to the spread of AMR (Malik et al.,2025). These factors highlight the poultry industry as a significant reservoir of emerging resistant pathogens.
ANTIMICROBIAL RESISTANCE IN DAIRY CATTLE
Misuse of antibiotics in dairy herds contributes to declining susceptibility among bacterial pathogens, especially mastitis-associated E. coli. Research has documented high resistance levels to widely used drugs such as amoxicillin (94.5%), ampicillin (89.5%), and tetracycline (89.5%), alongside the detection of resistance genes such as tetA in 100% tetracycline- resistant E.coli and blaTEM-1 in 38.9% isolates. The presence of multidrug-resistant E. coli in dairy systems indicates excessive antimicrobial usage and poses direct risks to consumers through contaminated milk and indirect risks via environmental dissemination (Bag et al.,2021).
ANTIBIOTIC RESIDUES IN FOOD PRODUCTS: A SERIOUS THREAT
Many antibiotics used in poultry and dairy animals often overlap with those used in humans. Their indiscriminate use causes bacterial resistance and contributes to the contamination of milk, meat and eggs with antibiotic residues. These residues pose toxic effects on humans. The presence of antibiotic residues in food products contributes to reduced drug effectiveness in treating human infections. Poultry meat and products are common reservoirs of emerging antimicrobial resistant bacteria that can inhabit human food chains. Retail poultry meat is a documented source of AMR pathogens such as multidrug resistant Klebsiella species, posing a major foodborne threat (Tanni et al., 2025). A study conducted in Bangladesh on milk samples recorded the highest prevalence of oxytetracycline (OTC) (Beldie et al.,2021), indicating excessive and non-regulated antibiotic use. In heat treated milk, enrofloxacin are intact due to their thermostability (Widiyanti et al.,2022), chlortetracycline and tetracycline are also intact in milk due to their ultrahigh and high thermostability (Cervini et al.,2016). These findings reflect the critical concern, showing the potential risk posed by antibiotic residues to human, animal and environmental health.
THE WAY FORWARD: STRATEGIES TO REDUCE ANTIMICROBIAL RESISTANCE
1.NANOPARTICLES AS ALTERNATIVES TO ANTIBIOTIC GROWTH PROMOTERS (AGP)
Though its application in veterinary science is still experimental (Scott, 2007), it has significant development and is regarded as cutting edge technology of this modern era. Small Nanoparticles (NP) will have a large surface area, higher reactivity, higher solubility, which will help achieve higher bioavailability when given orally (Abd El- Ghany et al.,2021). Used in smaller amounts, enhance profits, improves growth performance by enhancing ingestion, absorption and nutrient assimilation (Qadeer et al.,2024). Most frequently used NPs as a substitute for AGP’s are inorganic NPs, such as copper (CuNPs), Zinc (ZnNPs), Silver (AgNPs), Gold (AuNPs), Selenium (SeNPs) (Abreu et al.,2023). Though many alternatives are available, using nanoparticles is a promising and economic alternative.
2.CHLOROGENIC ACID FROM COFFEE SOLID WASTE- A WONDER FOR AMR
Recent studies highlight that coffee solid waste consists of phenolic compounds- chlorogenic acid (Cg-A) or 3-caffeoylquinic acid- a secondary metabolite abundant in plants (Nguyen et al.,2024) with antidiabetics, anti-microbial, anti-inflammatory agents, anti-tumour properties (Nguyen et al.,2024; Firmanda et al.,2022). Besides coffee beans, Cg- A can also be extracted from husk, silver skin, pulp and other residues. Its antimicrobial activity functions through multiple mechanisms such as efflux pump suppression and membrane damage in Methicillin resistant Staphylococcus aureus (MRSA) infections (Yang et al.,2018) and exhibiting strong binding affinity -8.2 kcal/mol against MRSA (Nandhini et al.,2023). Additionally, combination of Cg-A and antibiotics has been reported to inhibit extracellular bacterial mobility, pyocyanin production, elastase activity in Multidrug Resistant (MDR) Pseudomonas (Xu et al.,2022) and also exhibits activity against fluconazole-resistant Candida albicans (Rocha da Silva et al.,2022). The integration of natural compounds like Cg-A with trational antimicrobials offers additive or synergistic effects, making it a promising alternative strategy in combating antimicrobial resistance (Xu et al.,2022).
3.PROPHYLACTIC ALTERNATIVES
Prophylaxis mainly focuses on preventing diseases before they appear, so the dependence on antimicrobials becomes much lower. In livestock and poultry farms, these preventive steps aim to keep the animals healthy and resilient, making them less likely to develop infections. Prophylactic approaches play a crucial role in reducing the burden of AMR by decreasing infection incidence and lowering antibiotic use.
3.1.IMMUNE MODULATORS
Immune modulators including synthetic CpG-containing oligonucleotides, antimicrobial peptides and passive transfer of antibodies are gaining attention as alternative strategies for disease prevention (Koo et al.,2006). Synthetic CpG-ODNs targeting pathogen-specific bacterial DNA have shown immunoprotective effects in livestock and poultry (Weiner et al.,1997). These modulators can either stimulate or regulate host immune responses, thereby reducing reliance on conventional antimicrobials.
3.2PHAGE THERAPY
Pathogenic bacteria are killed by lysis in phage theraphy. These phages are specific to target bacteria and hence serve as a potential therapeutic agent. Phage therapy has been successfully used as an alternative to antibiotics to reduce shedding of Salmonella enteritidis, E. coli, and other pathogenic bacteria in livestock (Ahmadi et al., 2016).
3.3VACCINATIONS
Vaccination is one of the most effective methods for disease prevention and reducing the need for antibiotics. Vaccination remains a key tool for controlling Avian Pathogenic E.coli (APEC) infections and reducing antibiotic dependence. Although genetic diversity within APEC strains makes vaccine development challenging, vaccination can significantly lower disease impact in both layer and broiler flocks (Christensen et al.,2021). Several commercial vaccines are available, including subunit vaccine Nobilis INAC and live-attenuated Poulvac formulations (Watts et al.,2024). In India, more focus should be given to increasing vaccine use, awareness and coverage in livestock.
4.THERAPEUTIC ALTERNATIVES
Administering Selenium and Vitamin E during the peripartum period improves the immune function of dairy cattle, enhances neutrophil chemotaxis, and minimizes the possibility of antibiotic use (Hogan et al.,1990). Ozone therapy disrupts the cell membrane of microbes by diffusing through the protein coat of nucleic acids, ultimately killing microbes and viruses (Duricic et al.,2014). Ethno-veterinary medicine can be used in primary healthcare of livestock. These practices minimize antibiotic residue risk in livestock products (Ranganathan, 2017). Supplementation of rare earth mineral (lanthanum, scandium, etc.,) and yeast (Saccharomyces cerevisiae) said to have equal performance in pigs which is compared with ZnO and antibiotics (Han et al.,2010).
5.REGULAR TESTING OF ANTIBIOTIC RESIDUES
Routine testing of milk loads and meat samples is essential to ensure that antibiotic residues do not enter the food chain (Wray and Gnanou, 2000).
- FOLLOWING WITHDRAWAL PERIOD AND MAXIMUM RESIDUE LIMITS (MRLs)
In general, the minimum withdrawal period for milk after antibiotic treatment is 7 days, and for meat it is 28 days. The MRLs are decided based on toxicological data (Gupta, 2012). Strict adherence to withdrawal periods ensures that antibiotic residues do not enter the food chain.
- MANAGEMENT PRACTICES
Adoption of good husbandry practices (Van de Weerd et al., 2009) and organic livestock farming (Sapkota et al., 2011) with improved hygiene indirectly reduces the need for antibiotics. Manure management practices are essential, as a high proportion of antibiotics excreted by livestock in manure, altering the soil microbial ecosystem (Kumar et al., 2005).
- EDUCATION AND CREATING AWARENESS
Education among farmers regarding the harmful effects of AMR and creating awareness about the misuse of antibiotics, high doses and unnecessary treatments is crucial to reduce antibiotic dependency (Li et al., 2017).
9.REGULATORY CONTROL FOR ANTIBIOTIC USAGE IN LIVESTOCK
India’s National Action Plan on AMR (2017–2021) and Kerala’s KARSAP emphasize antimicrobial stewardship and regulated antibiotic usage (NAP-AMR, 2017-2021; KARSAP, 2018). The Food Safety and Standards Act (2006) (GOI, Government of India, 2006) and the Food Safety and Standards (Contaminants, Toxins and Residues) Regulations (2011) enforce permissible residue limits and improve food safety.
10.AMR – ONE HEALTH APPROACH
Coordinated efforts across human, veterinary, and environmental sectors are essential. The one health framework supports integrated surveillance and policy implementation to effectively combat AMR (Wang et al., 2024).
CONCLUSION
Antimicrobial resistance poses a critical challenge to India’s livestock and poultry sectors, threatening animal productivity, food safety and public health. Effective combat against AMR demands on implementation of antimicrobial stewardship programmes, regular testing of antibiotic residues, encouraging farm level awareness, promoting alternatives to antibiotics, enforcing policy regulations and one health approach- integrating veterinary, medical and environmental sectors. With responsible use, education and innovation, India can safeguard the effectiveness of antimicrobials ensuring animal health, food security and public well-being for future generations.
