Antimicrobials in Animal Production
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What is the primary reason for using antimicrobials in livestock populations after recovering from illness?

  • To reduce the risk of developing antibiotic resistance
  • To boost the immune system and prevent future infections (correct)
  • To improve nutrient absorption and promote growth
  • To eliminate all pathogens and prevent future outbreaks

    • Which antimicrobial class is most commonly used in the US for food-producing animals?

  • Sulfa drugs
  • Penicillins
  • Macrolides
  • Tetracyclines (correct)

    • Which two antimicrobial classes are most frequently used in general, irrespective of the animal species?

  • Tetracyclines and Ionophores (correct)
  • Aminoglycosides and Penicillins
  • Sulfa drugs and Macrolides
  • Tetracyclines and Penicillins

    • Which livestock sector uses the highest amount of medically important antimicrobials in the US?

    <p>Cattle (D)</p> Signup and view all the answers

    What is the primary reason for the use of antimicrobials to promote gut immunity?

    <p>To reduce the level of inflammation in the gut (B)</p> Signup and view all the answers

    What is a potential consequence of excessive inflammation triggered by certain pathogens?

    <p>Suppression of the immune response making the host more vulnerable (A)</p> Signup and view all the answers

    What is a key reason why excessive inflammation is considered physiologically costly for the host?

    <p>It uses energy that could be used for growth and other functions (B)</p> Signup and view all the answers

    What is the trend observed in the usage of medically important antimicrobials in poultry?

    <p>A gradual decrease in usage while the use of ionophores increases (D)</p> Signup and view all the answers

    Which of the following antimicrobial classes is specifically mentioned as NOT being approved for food-producing animals in the provided text?

    <p>Chloramphenicol (D)</p> Signup and view all the answers

    What is the major streptogramin used therapeutically to treat poultry, bovine, and porcine bacterial enteric diseases?

    <p>Virginiamycin (C)</p> Signup and view all the answers

    Which of the following is a reason why the use of sulfonamides can be problematic in treating poultry infections?

    <p>Sulfonamides can lead to the development of antibiotic resistance in pathogens like Escherichia coli. (A)</p> Signup and view all the answers

    What is the primary mechanism of action for aminoglycosides like gentamicin and neomycin when used in livestock production?

    <p>Interfering with bacterial protein synthesis (B)</p> Signup and view all the answers

    What is the significance of the mcr-1 gene discovered in Escherichia coli isolated from pig meat?

    <p>It provides resistance to a last resort antibiotic, polymyxin-E (colistin), used to treat Gram-negative bacterial infections. (B)</p> Signup and view all the answers

    What is a potential consequence of humans interacting with livestock and companion animals?

    <p>Both B and C (D)</p> Signup and view all the answers

    Which of the following organizations has committed to reducing the use of antibiotics in food production?

    <p>All of the above (D)</p> Signup and view all the answers

    Based on information provided, what is the common mechanism of action for the development of antibiotic resistance?

    <p>Mutations within genes encoding enzymes responsible for metabolizing antimicrobials. (A)</p> Signup and view all the answers

    What is the rationale behind banning antibiotics used as growth promoters (AGP)?

    <p>To reduce the selection pressure for AMR microbes. (A)</p> Signup and view all the answers

    Why is the detection of the mcr-1 gene in diverse environments a cause for concern?

    <p>It suggests potential for the spread of resistance to a last resort antibiotic, posing a threat to human and animal health. (A)</p> Signup and view all the answers

    What is a plasmid, as defined in the given text?

    <p>A small DNA molecule that is physically separated from chromosomal DNA and can transfer between species. (A)</p> Signup and view all the answers

    Which of the following is NOT mentioned as a possible source of AMR microbes in the environment?

    <p>River sediments (D)</p> Signup and view all the answers

    What is a major contributor to the development of AMR, according to the provided content?

    <p>Overuse and misuse of antimicrobials in animals. (C)</p> Signup and view all the answers

    What is a potential consequence of banning antibiotics used as growth promoters (AGP), even if it doesn't reduce AMR?

    <p>It may delay the further development and spread of AMR. (D)</p> Signup and view all the answers

    The strategy of prolonging the use of therapeutic antimicrobials for disease treatment requires...

    <p>All of the above (D)</p> Signup and view all the answers

    Why might monitoring antimicrobial dose be difficult to implement in livestock?

    <p>All of the above (D)</p> Signup and view all the answers

    Which of the following approaches focuses on preventing the development of antimicrobial resistance by introducing alternative antimicrobial compounds that target different bacterial mechanisms?

    <p>Antimicrobial cycling (A)</p> Signup and view all the answers

    Which of the following approaches aims to enhance animal health and potentially reduce antimicrobial use by harnessing the power of the animal's natural defenses?

    <p>Using other compounds to attenuate bacterial virulence (B)</p> Signup and view all the answers

    Which two approaches are most likely to be effective in reducing the use of broad-spectrum antimicrobials?

    <p>Personalized antimicrobial therapy and Gene editing (C)</p> Signup and view all the answers

    Which of the following approaches focuses on altering the environment within the animal's gut to promote beneficial bacteria populations and potentially reduce the need for antimicrobials?

    <p>Eco-biological approaches to modify the microbiome (C)</p> Signup and view all the answers

    Which of the following alternative approaches is most likely to help reduce the development of antimicrobial resistance by targeting specific bacteria within the animal's gut?

    <p>Personalized antimicrobial therapy (C)</p> Signup and view all the answers

    Which of these strategies aims to minimize the spread of pathogens and reduce antimicrobial exposure on farms?

    <p>Using an on-farm biosecurity program (B)</p> Signup and view all the answers

    Which strategy focuses on ensuring the quality and effectiveness of antimicrobials currently available in the market?

    <p>Testing the quality of generic antimicrobials (A)</p> Signup and view all the answers

    Which of these strategies directly addresses the issue of antimicrobial use in different countries, even those where regulations may be less stringent?

    <p>Banning AGPs (C)</p> Signup and view all the answers

    What is the primary concern associated with the use of combined antimicrobial therapy?

    <p>It can have detrimental effects on the host microbiome (B)</p> Signup and view all the answers

    Which of these is NOT considered a research priority to address antimicrobial resistance?

    <p>Measuring drug pharmacokinetics in real-time (C)</p> Signup and view all the answers

    Which of these stakeholders is NOT directly involved in the effort to regulate antimicrobial usage?

    <p>Feed companies (D)</p> Signup and view all the answers

    What is the primary challenge associated with developing novel antimicrobials?

    <p>High cost and uncertain financial returns (B)</p> Signup and view all the answers

    Which of these is a potential consequence of using antimicrobials in animal feed without proper education and oversight?

    <p>All of the above (D)</p> Signup and view all the answers

    Which of the following practices can contribute to the development of antimicrobial resistance (AMR)?

    <p>Using antimicrobials to prevent disease in livestock, rather than treating existing infections (A), Administering antimicrobials at higher than recommended doses (B), Failing to complete the full prescribed course of antibiotics (C)</p> Signup and view all the answers

    What is the primary reason why sub-therapeutic levels of antimicrobial treatment can contribute to AMR?

    <p>Sub-therapeutic doses select for microbes with mutations that confer resistance (A)</p> Signup and view all the answers

    How do heavy metals contribute to the development of AMR?

    <p>Heavy metals create an environment that favors the growth of AMR microbes (D)</p> Signup and view all the answers

    Which of the following is NOT mentioned as a factor contributing to the emergence of AMR in the text?

    <p>Use of genetically modified crops with built-in resistance to herbicides (A)</p> Signup and view all the answers

    How does the use of poor quality or expired antimicrobials contribute to AMR?

    <p>Expired antimicrobials lose their potency and become ineffective (C)</p> Signup and view all the answers

    Which of these contributes to the spread of AMR from agricultural environments into the wider ecosystem?

    <p>All of the above (D)</p> Signup and view all the answers

    Why is antimicrobial resistance considered a global problem?

    <p>All of the above (D)</p> Signup and view all the answers

    What is the main reason why fifty percent of all antimicrobials prescribed to humans are considered unnecessary?

    <p>Antibiotics are often prescribed for viral infections, which they cannot treat (A)</p> Signup and view all the answers

    Study Notes

    Antimicrobials for Controlling Infectious Disorders

    • Antimicrobial use in animal production is common practice to minimize microbial stressors. Antimicrobials are categorized as antibiotics, antifungals, antivirals, and antiparasitics.
    • Antibiotics are most commonly used historically. In 2015, two-thirds of global antibiotic production was used in animal husbandry.
    • Global livestock antibiotic use (cattle, sheep, chickens, and pigs) in 2020 was 99,502 tonnes, projected to increase by 8% by 2030.
    • Top 5 user countries are China, Brazil, India, USA, and Australia.
    • Global aquaculture antibiotic use in 2017 was 11,308 tonnes, projected to increase by 33% by 2030.
    • Top user countries include China, India, Indonesia, and Vietnam.
    • Antibiotics excreted in animal waste (feces and urine) can impact the environment, at rates of 30-90%.

    Driving Forces Behind Antimicrobial Usage

    • Producer-driven increasing livestock productivity
    • Consumer-driven increasing product quality
    • Consumer and food processor-driven improvements in product uniformity
    • Consumer and producer-driven improvements in animal welfare through reduced disease
    • Society-driven reducing risks of zoonosis

    Increasing Livestock Productivity with Antimicrobials

    • Antimicrobials boost productivity via growth promotion and reduced disease-related losses.
    • Sub-therapeutic concentrations (2.5-125 ppm) of antimicrobials in animal feed/water are considered antimicrobial growth promoters (AGPs).
    • AGPs were first used in 1946, and approved in 1951 by the US FDA.
    • AGPs are most effective in improving growth of pigs and poultry under poor hygiene early in life, crucial for neuroendocrine immune system development.
    • Effectiveness of AGPs is less certain with improved housing, feed, and water quality; usage may reduce producer profits.

    Summary of AGP Usage in Canadian Livestock

    • Summary of AGPs previously used in Canadian livestock production is provided. (Slide 4)

    AGP Mechanisms of Action

    • Exact mechanisms of antimicrobial action on animal growth are yet to be determined, but vary among antimicrobials.

    Interactions of Antimicrobials with Gut Microbiota

    • Antimicrobial effects can induce subtle changes in gut microbial populations, which optimise nutrient availability, control pathogens, and support a healthy immune response without becoming overwhelming.
    • Reduction in microbial competition for nutrients or reduction in microbial metabolite production that inhibit growth is also a possible outcome.
    • Therapeutic levels of certain antimicrobials can manage gut inflammation, regulate host immune response, (especially T cell sub-populations), and improve innate immune response.
    • Inflammation may be triggered or made worse by some pathogens (e.g., viruses) as a strategy to avoid immune detection.
    • The body directing energy towards immune-related processes results in reduction in growth, loss of appetite, and muscle breakdowns.

    2016 US Antimicrobials Usage

    • Tetracyclines (70%), penicillins (10%), macrolides (7%), sulfas (4%), and aminoglycosides (4%) were the medically important antimicrobials used in food-producing animals in the US between 2015-2016.
    • Tetracyclines (42%) and ionophores (33%) are the most commonly used antimicrobials in the US.
    • Usage by species (cattle, swine, turkey, chicken) is provided. (Slide 8)
    • Poultry antibiotic use has been declining, while the use of ionophores has been increasing.

    Antimicrobials, Tolerance Levels, Withdrawal Times

    • US and EU approved antimicrobials, corresponding tolerance levels and withdrawal times for drug residues in different tissues are available. (Slide 9)

    Consequences of Antimicrobial Usage

    • Antimicrobial usage in livestock leads to exposure of consumers to bioactive drug residues (i.e., allergies, gut microbiota), negatively affect environment (algae, invertebrates, and fish), and potentially lead to antimicrobial resistant (AMR) pathogens, which can be transferred between species.
    • AMR in microbes refers to the ability to be unaffected by the antimicrobial growth inhibitors.

    Mcr-1 and Resistance to Colistin

    • The mcr-1 gene, discovered in 2015, confers resistance to colistin, a last-resort antibiotic.
    • Colistin usage in animals has been banned in parts of China, despite mcr-1 presence in livestock and pets worldwide.
    • Horizontal transfer of plasmids containing mcr-1 has occurred, and is found in other species such as Salmonella.

    Aquaculture and Antimicrobial Resistance

    • AMR levels in fish bacterial pathogens correlate with those in humans.

    Factors Contributing to Antimicrobial Resistance Development

    • The misuse of antimicrobials (higher doses than needed, use for prevention, use in sub-therapeutic levels) leads to human exposure and development of AMR in environmental microbes, including pathogens for human or animal health.
    • Poor quality or expired antimicrobials reduce therapeutic dosing and promote resistance.
    • Antimicrobial residues in animal waste and contaminated environments (e.g., soil, water, and aquatic environments in aquaculture) can spread AMR.
    • Heavy metals and biocides (e.g., disinfectants, solvents) can promote AMR.
    • Use of nitrogen fertilizers can contribute to the growth of AMR microbes.

    Strategies to Reduce Antimicrobial Resistance

    • Limiting/stopping antibiotics for growth promotion
    • Reducing overuse of antibiotics
    • Providing access to non-medicated feed options
    • Implementing strategies for stricter regulations and monitoring
    • Developing new antimicrobial treatment strategies
    • Developing new alternative approaches (e.g., bacteriophage, gene editing, microbiome modification, etc.)

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    Unit 3 Antimicrobials Notes 2025 Jan 24 PDF

    Description

    Explore the role of antimicrobials in controlling infectious disorders within animal production. This quiz covers the types of antimicrobials, their usage statistics, and the driving forces behind their increasing application in livestock. Understand the implications for both animal health and environmental impact.

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