ANTIMICROBIAL RESISTANCE: A ONE HEALTH PERSPECTIVE
Reshma M. M.1, Marita Dias2
1M. V. Sc. Scholar, Department of Poultry Science, 2M. V. Sc. Scholar, Department of Veterinar Public health, College of Veterinary and Animal Sciences, Pookode
Antimicrobial resistance (AMR) is the ability of bacteria, viruses, fungi, and parasites to adapt and thrive in the presence of medications that had previously adversely impacted them. Including the anticipated $35 billion in productivity losses, the Centres for Disease Control and Prevention (CDC) estimates that antibiotic resistance drives up direct healthcare spending in the United States by $20 billion yearly. One health is “the collaborative effort of multiple health science professions, together with their related disciplines and institutions—working locally, nationally, and globally to achieve optimal health for people, domestic animals, wildlife, plants, and our environment”. The health of these connected habitats (the emphasis of the One Health concept) may pose a threat to human health since several interrelated human, animal, and environmental habitats might influence the origin, evolution, and spread of antibiotic resistance.
A One Health concept, which acknowledges the interdependence of human, animal, and environmental health, is necessary to properly address this pressing issue. Antimicrobials are employed quite differently in the human and non-human sectors of the economy. Antimicrobials are mostly used to treat clinical infections in individual patients, with a small amount of preventive usage also occurring rarely in groups (e.g., meningococcal disease prevention) or in individuals (e.g., post-surgery). Antimicrobials are mostly supplied on an individual basis to treat infection, with prophylaxis occurring rarely, such as post-surgery, in companion animals (such as dogs, cats, pet birds, and horses). Antimicrobials are also utilised therapeutically to treat specific clinically ill animals in the food-producing animal sector, such as dairy cows with mastitis. However, due to practicality and efficiency considerations, antimicrobials are frequently given to entire groups (such as pens of pigs or flocks of broilers) through feed or water, either for prophylaxis (to healthy animals at risk of infection) or metaphylaxis (to healthy animals in the same group as diseased animals). In the animal industry that produces food, growth stimulation, prophylaxis, and metaphylaxis make up by far the biggest quantities of antimicrobials utilised.
Most antimicrobial classes are utilised by both people and animals, including aquaculture, which includes the farming of both fish and shellfish. Only a small number of antimicrobial classes, such as carbapenems, are only used on humans. A few groups are also only permitted for usage in animals (e.g., ionophores and flavophospholipols), mostly due to their toxicity to humans. When the same antibiotic classes are used on people and animals, concerns with antimicrobial resistance and imbalances of risk and benefit across other sectors also present themselves. Broad spectrum beta-lactam antibiotics of the third generation cephalosporins are often utilised in both people and animals. For a variety of frequently serious infections in people, including bloodstream infections caused by Escherichia coli and other bacteria, as well as infections in the community, such as Neisseria gonorrhoea, cefotaxime, ceftriaxone, and other members of the class are often used in hospital settings. Ceftiofur, along with cefpodoxime, cefoperazone, and cefovecin, is the main third-generation cephalosporin for veterinary usage. Animals are treated with ceftiofur through injection for a variety of ailments, including septicemia, arthritis, and pneumonia. Ceftiofur, however, is also used in mass treatment (metaphylaxis or prophylaxis), either in accordance with a valid label claim (for example, injecting cattle in feedlots to manage bovine respiratory illness) or off-label (for instance, injecting hatching eggs or day-old chicks to prevent E. coli infections). Extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases are the major mediators of resistance to third generation cephalosporins. E. coli and K. pneumonia are increasingly often resistant to third generation cephalosporins, which is unfortunate. Genes encoding resistance to tetracyclines, aminoglycosides, and sulfonamides are typically found along with genes encoding resistance to other types of antimicrobials. Therefore, using other antimicrobials in animals, such as tetracyclines fed as feed, might favour ESBL strains of bacteria.
Colistin belongs to the polymyxin family of antibiotics and has been used for more than 50 years in both humans and animals. When given systemically, polymyxins commonly induce nephrotoxicity and neurotoxicity in humans. Thus, up until recently, its principal applications were for topical use and the inhalation therapy of infections in cystic fibrosis patients. However, colistin is currently utilised considerably more commonly as a last-resort injectable medication for the treatment of multi-resistant gram-negative infections, such as E. coli and Pseudomonas aeruginosa that are resistant to carbapenems. Colistin contrasts with third generation cephalosporins in certain significant One Health aspects of antimicrobial resistance. Because of its systemic toxicity and the accessibility of alternative, safer, and more potent antimicrobials for a long time, colistin was mostly applied topically to individuals. However, there has been a rising demand for this medication to systematically treat serious, life-threatening infections in people in many countries due to the evolution of multi-drug resistance in many Gram-negative bacteria. Even though the drug class is initially thought to be of less importance, the colistin case demonstrates (yet again) that using large quantities of antibiotics for group treatments or growth promotion in animals can result in significant antimicrobial resistance problems for human health. This is because the relative importance of antibiotics to human health.
Antimicrobial resistance is bad for health because it makes antimicrobial therapy less effective and makes infections more severe, more common, and more expensive. There is a growing body of research showing that the use of antibiotics in animals has a significant role in the development of antimicrobial resistance in some human infections, particularly in the case of common enteric pathogens including Salmonella spp., Campylobacter spp., Enterococcus spp., and E. coli. In order to address the antibiotic resistance challenge, the World Health Organisation (WHO) and other international organisations, such as the Food and Agriculture Organisation (FAO) and the World Organisation for Animal Health (OIE), as well as several individual nations, have created detailed action plans. In order to fight antibiotic resistance, the WHO Plan adopts a One Health strategy, and it encourages member nations to follow suit when creating their own action plans. The WHO Global Plan is supported by five fundamental pillars are as follows, improve awareness and understanding of antimicrobial resistance through effective communication, education and training, strengthen the knowledge and evidence base through surveillance and research, reduce the incidence of infection through effective sanitation, hygiene and infection prevention measures, Optimize the use of antimicrobial medicines in human and animal health and develop the economic case for sustainable investment that takes account of the needs of all countries, and increase investment in new medicines, diagnostic tools, vaccines and other interventions.
With the exception of novel antimicrobial classes, history has demonstrated that it is not possible to neatly divide antimicrobial classes into those exclusively for use in human or non-human sectors. As long as there are few or no alternatives, they should presumably only be used in humans. The issue for One Health is to make sure that usage of these medications is optimal on the whole given that the bulk of classes will be accessible in both sectors. This is likely to be accomplished when antimicrobials used in both sectors are only used for therapeutic purposes, never for growth promotion, and only rarely for prophylaxis. It is also likely to be accomplished when we better regulate the types and amounts of antimicrobials used, as well as the numbers of resistant bacteria we allow to exist.
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