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Questions and Answers
What is a characteristic of bacteriostatic agents?
What is a characteristic of bacteriostatic agents?
- They are always more effective than bactericidal agents.
- They inhibit bacterial growth and require the immune system to eliminate bacteria. (correct)
- They kill all types of bacteria instantly.
- They work independently of the patient's defense mechanism.
What can happen when bacteriostatic agents are given at very high doses?
What can happen when bacteriostatic agents are given at very high doses?
- They have no added effect on bacterial infection.
- They trigger an immediate immune response.
- They become ineffective against all bacterial strains.
- They may exhibit bactericidal properties. (correct)
Which mechanism of action is NOT associated with bacteriostatic agents?
Which mechanism of action is NOT associated with bacteriostatic agents?
- Inhibitors of cell wall synthesis
- Inhibitors of nucleic acid functions
- Inhibitors of protein synthesis
- Inhibitors of toxin production (correct)
Which of the following statements regarding bacteriostatic agents is true?
Which of the following statements regarding bacteriostatic agents is true?
What is a potential consequence of using agents that kill normal bacterial flora?
What is a potential consequence of using agents that kill normal bacterial flora?
What defines intrinsic resistance in bacteria?
What defines intrinsic resistance in bacteria?
Which antibiotic is produced by Streptomyces griseus?
Which antibiotic is produced by Streptomyces griseus?
How is acquired resistance different from intrinsic resistance?
How is acquired resistance different from intrinsic resistance?
What is the primary purpose of using antimicrobial drugs at subtherapeutic concentrations in animals?
What is the primary purpose of using antimicrobial drugs at subtherapeutic concentrations in animals?
What is an example of a mechanism through which acquired resistance occurs?
What is an example of a mechanism through which acquired resistance occurs?
Which of the following best describes prophylaxis in the context of antimicrobial use in animals?
Which of the following best describes prophylaxis in the context of antimicrobial use in animals?
Which antibiotic is known to be ineffective against Gram-negative bacteria?
Which antibiotic is known to be ineffective against Gram-negative bacteria?
Which of the following is correctly matched to its producing organism?
Which of the following is correctly matched to its producing organism?
Which mechanism of action is NOT suggested for how subtherapeutic antibiotics enhance growth?
Which mechanism of action is NOT suggested for how subtherapeutic antibiotics enhance growth?
What is the significance of Gram-negative bacteria having intrinsic resistance to certain antibiotics like penicillin?
What is the significance of Gram-negative bacteria having intrinsic resistance to certain antibiotics like penicillin?
What does the term 'metaphylaxis' refer to in antimicrobial use?
What does the term 'metaphylaxis' refer to in antimicrobial use?
Which of the following antibiotics is produced by Penicillium notatum?
Which of the following antibiotics is produced by Penicillium notatum?
What is the Chemotherapeutic Triangle in relation to antimicrobial therapy?
What is the Chemotherapeutic Triangle in relation to antimicrobial therapy?
Which of the following is an independent effect of using subtherapeutic antimicrobial drugs?
Which of the following is an independent effect of using subtherapeutic antimicrobial drugs?
Why is the exact mechanism by which subtherapeutic antibiotics enhance growth poorly understood?
Why is the exact mechanism by which subtherapeutic antibiotics enhance growth poorly understood?
Which of the following factors is NOT considered in effective antimicrobial therapy?
Which of the following factors is NOT considered in effective antimicrobial therapy?
What type of antibiotic is bacitracin categorized as?
What type of antibiotic is bacitracin categorized as?
Which mechanism allows bacitracin to kill bacteria?
Which mechanism allows bacitracin to kill bacteria?
What is a common side effect related to the administration of certain antibiotics mentioned in the context?
What is a common side effect related to the administration of certain antibiotics mentioned in the context?
Which dosage is recommended for cefotaxime in dogs and cats?
Which dosage is recommended for cefotaxime in dogs and cats?
What is required for bactericidal activity of bacitracin?
What is required for bactericidal activity of bacitracin?
Which cephalosporin antibiotic retains efficacy despite bacterial β-lactamase production?
Which cephalosporin antibiotic retains efficacy despite bacterial β-lactamase production?
What is the maximum recommended dosage of cefadroxil for dogs and cats?
What is the maximum recommended dosage of cefadroxil for dogs and cats?
Which adverse effect is associated with intravenous injection of certain antibiotics?
Which adverse effect is associated with intravenous injection of certain antibiotics?
Which type of antimicrobial use is primarily focused on disease prophylaxis in feedlot calves?
Which type of antimicrobial use is primarily focused on disease prophylaxis in feedlot calves?
What is the primary route of administration for therapeutic antimicrobial use?
What is the primary route of administration for therapeutic antimicrobial use?
Which type of antimicrobial use is intended for growth promotion in healthy animals?
Which type of antimicrobial use is intended for growth promotion in healthy animals?
In what scenario might some non-diseased animals be included in therapeutic antimicrobial use?
In what scenario might some non-diseased animals be included in therapeutic antimicrobial use?
What is the goal of prophylactic antimicrobial use?
What is the goal of prophylactic antimicrobial use?
Study Notes
Antimicrobial Use Types
- Therapeutic Use: Treatment of clinically ill animals; includes preventing/control of disease.
- Metaphylactic Use: Disease prophylaxis in vulnerable animals, often conducted during outbreaks; typically given by injection or in feed/water.
- Prophylactic Use: Prevention of diseases in groups; often applied to healthy populations at risk but may include subclinical animals.
- Subtherapeutic Use: Enhances growth and feed efficiency groupwise; does not show evident disease resistance.
Mechanism of Subtherapeutic Use
- Enhances growth likely through:
- Suppression of normal intestinal bacteria increasing nutrient availability.
- Reduction of harmful bacterial metabolites.
- Thinning of the intestinal wall for better nutrient absorption.
- Anti-inflammatory effects unrelated to gut microbiota.
- Inhibition of subclinical diseases.
Chemotherapeutic Triangle
- Effective therapy requires understanding:
- Interactions between host animal, pathogen, and drug.
- Use of antimicrobials may disrupt normal bacteria, leading to superinfections.
Bacteriostatic vs. Bactericidal
- Bacteriostatic Agents: Inhibit bacterial growth; require the host's immune response to eliminate bacteria.
- May temporarily antagonize some bactericidal drugs but can be effective at high doses or in high concentrations.
- Mechanisms of Action:
- Inhibition of cell wall synthesis.
- Disruption of cell membranes.
- Interference with protein synthesis.
- Inhibition of nucleic acid functions.
- Inhibition of folate cofactor synthesis.
Common Antibiotics and Their Origins
- Gentamicin: Micromonaspora purpurea
- Kanamycin: S. kanamyceticus
- Penicillin: Penicillium notatum; P. chrysogenum
- Oxytetracycline: Streptomyces rimosus
- Streptomycin: Streptomyces griseus
Bacterial Resistance Mechanisms
- Intrinsic Resistance: Natural characteristics of bacteria that prevent susceptibility to certain antibiotics (e.g., gram-negative bacteria’s resistance to penicillin).
- Acquired Resistance: Results from genetic alterations; resistance genes can be acquired through mutations or horizontal gene transfer via plasmids.
Antibiotic Side Effects and Toxicities
- Gastrointestinal issues such as nausea, vomiting, diarrhea.
- Local irritation, pain from injections, and complications like thrombophlebitis from IV administration.
Dose Rates for Penicillins
- Cefadroxil: Dogs/cats 22 mg, Horses 25 mg.
- Cephalexin: Dogs/cats 22 mg; Horses 22-33 mg.
- Ceftiofur: Cattle 1 mg by IM; intervals vary by species.
Bacitracin
- Cyclic decapeptide antibiotic; Bacitracin A is the most active form.
- Mechanism: Inhibits bacterial cell wall synthesis and function by blocking phosphorylase reactions.
- Requires divalent cations like zinc for bactericidal activity.
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Description
This quiz covers the types, purposes, and methods of antimicrobial administration in diseased animals. It includes therapeutic uses and various routes of administration such as injection, feed, and water. Test your knowledge on this critical aspect of veterinary medicine.
