Dissemination of Antimicrobial Resistance through Food Animals
Archana1*, Sourabh Swami2, Himani Singh2 and Priyeranjan2
- PhD scholar, Department of Veterinary Public Health & Epidemiology, Bihar Veterinary College, BASU, Patna-14
- M.V.Sc. scholar, Department of Veterinary Public Health & Epidemiology, Bihar Veterinary College, BASU, Patna-14
*Corresponding author
email id:archi2lalio@gmail.com
Abstract
Antimicrobial resistance (AMR) is a loomimg public health crisis. Every year more than 25000 people die from infections caused by antibiotic-resistance bacteria (WHO, ). AMR is also a food safety problem; antibiotics use in food animals for clinical purpose, prevention of disease and growth promotion, which allows bacteria and resistance genes to spread from food animals to humans through the food chain, but also through direct contact with food animals or environmental mechanisms. Eventually, that results in the human infections by resistant bacteria, that are difficult or impossible to cure. Tackling antibiotic resistance requires a holistic, intersectorial and multifaceted approach with effective coordination of action and exchange of information among the agriculture, food, veterinary and health sectors.
Introduction
The introduction of the Penicillin in the year 1940s, has been recognized as a greatest advances in the therapeutics. Penicillin was nicknamed as “wonder drugs” or “magic bullets”, due to its ability to kill a wide range of pathogenic bacteria. As time passed by many more antibiotics started to came in the market.
Realising its importance as growth promoter it was rampantly used in livestock and poultry to increase their growth and productivity. As a result the drug residue left in their faeces contaminated the environment and triggered the selection of antibiotic resistant microbes over the sensitive ones. Similarly, the drug residue in animal products like meat and milk can also predispose gut flora of its consumers to develop antibiotic resistance.
Transmission of resistance from food animals
The continuous and injudicious use of antibiotics in animals for the treatment and as growth promotor creates a ideal condition for the development and spread of resistance in bacteria. Resistant bacteria developed in animals may reach to the humans through food, water, mud, and manure, which are used s fertilizers. In fact, there is indisputable evidence that foods from different animal sources and all food processing stages contain a large number of resistance bacteria. Homologous relationship between drug resistance bacteria in humans and animals have been identified in the most common food-borne pathogens, such as Extended spectrum Beta Lactamases (ESBLs) enterobacteriaceae, different types of enterococci, and methicillin-resistance Staphylococcus aureus (MRSA).
The antimicrobial resistance is disseminated mainly through plasmids (genetic material of bacteria) harboring antimicrobial-resistant genes. These genes can be transmitted from one bacterium to the another by the process of conjugation, transduction or transformation. The conjugation is the process by which a donor bacterium attaches to the recipient bacterium and transfers its genetic material.
Transduction is another process in which the genetic material of one bacterium is inserted into another bacterium via the bacteriophages (viruses that hack the genetic material of bacteria) through the lytic-lysogenic cycle. Transformation is yet another process in which the bacteria acquires the floating genetic material from their immediate environment. The phenomenon of antibiotic resistance is not new in the microbial world rather it has been there even before the first antibiotic was discovered. But the extent to which it can be dissiminated depends upon the selection of bacteria carrying antibiotic resistant genes. For example, the drug sensitive bacteria may get killed but the drug resistant bacteria may survive if the antibiotic is underdosed or not repeated as recommended by the competent veterinarian. As a result, the drug resistant bacteria colonizes and competitively excludes the drug sensitive bacteria. The next time we treat the patient with the same antibiotic it may not work due to predominance of drug resistant bacteria. Thus, we lose one of the precious antibiotics against that bacteria and the cycle may still go on if antibiotics are not used judiciously. The anology for underdosing can be correlated with the drug residue present in the animal products such as meat and milk that can dissiminate antibiotic resistance in humans. Similarly, the higher doses of antibiotics may be injurious to animal health particularly the liver and kidneys where drugs get metabolized. The high concentration of antibiotics may also provoke mutation in bacteria so that the bacterial population could survive in the stressful condition so created . Further, the drug residue level in milk and muscles may also get increased and as a result a little more time would be consumed for its clearance out of the body. This would lead to longer milk condemnation or delayed slaughter that can economically impact the farmers. Therefore, it is recommended that an antibiotic regimen should be completed in the dosage as prescribed by the competent veterinarian.
How to control and prevent antibiotic resistance ?
Awareness is the answer to this question. The one who is concerned with clinics and livestock are important pillars to prevent drug resistance in microbes. The inappropriate use of antibiotics in livestock should be discouraged. The antibiotics should not be used for growth promotion, viral illness, and unnecessarily in simple wound condition. The Indian cooking practices (high temperature) and the pasteurization temperature can destroy antibiotic residues in food but it is not true for all types of antibiotics as few of them remain potent even at 100ºC. Therefore, the proper withdrawl time as recommended by antibiotic manufacturer should be followed. The withdrawl time can be understood as the time span in which the products obtained from antibiotic treated animal is condemned to avoid its ill effect on consumers. Further, it is not just the drug residue responsible for antibiotic resistance, infact the stable genetic material surviving cooking temperature can also be acquired through the process of transformation in human gut. So, the better we are aware about these things the better we can control it. The practice of ethnoveterinary medicine may work as a panacea for long-term sustainable growth.
Conclusion
Antibiotics are an invaluable gift to humans that led to the progression of mankind as a whole. We can’t imagine a world without antibiotics as all our modern medicine would get paralyzed in the absence of it. According to a report published by O, Neill at World Health Organization (WHO) pointed out that by 2050; about 10 million people would die just because of antibiotic-resistant infections.
Proper awareness among farmers to a large extent can help to control antibiotic resistance. Further, the acceptance of ethnoveterinary practices by farmers can be a way forward but demands more research. At present, the judicious use of antibiotics must be propagated for sustainable development.
https://www.frontiersin.org/articles/10.3389/fmicb.2016.01881/full
