Antimicrobials Quiz 1

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Questions and Answers

What is the primary consideration before prescribing an antibacterial?

Whether bacteria are present and if an antibacterial will improve prognosis (correct)

The patient's previous prescription history

The overall cost of the treatment

The availability of the drug in local pharmacies

Which step involves identifying the likely causative organisms for infection?

Monitoring antimicrobial sensitivity

Presenting options to the client

Taking microbiological samples

Choosing the right drug for the right bug (correct)

When should antimicrobial sensitivity be monitored?

Before any clinical decision is made

During the initial consultation with the patient

After taking a sample and sending it for culture (correct)

Only when the patient shows signs of adverse drug reactions

What factors should be considered when evaluating the benefits and harms for an individual patient?

The potential therapeutic effect and the risks associated with treatment Signup and view all the answers

In what situation is it appropriate to use antimicrobials?

Only when there is evidence that it will reduce morbidity or mortality Signup and view all the answers

What distinguishes bactericidal antimicrobials from bacteriostatic antimicrobials?

Bactericidal antimicrobials kill bacteria. Signup and view all the answers

Which statement is true about time-dependent antimicrobials?

Efficacy is influenced by the duration above the MIC. Signup and view all the answers

In the context of antimicrobial drugs, what is meant by the term 'spectrum of activity'?

The range of Microbial species that the drug can act against. Signup and view all the answers

Which of the following statements about Gram +ve and Gram -ve bacteria is accurate?

Gram +ve bacteria are surrounded by a thick peptidoglycan cell wall. Signup and view all the answers

What is the primary characteristic of concentration-dependent antimicrobials?

Higher concentrations lead to more rapid bacterial count reduction. Signup and view all the answers

What is the purpose of recording and justifying protocol deviations?

To explain and justify the chosen course of action Signup and view all the answers

What does the minimum inhibitory concentration (MIC) indicate?

The lowest concentration that inhibits visible growth of a microorganism Signup and view all the answers

Why is it important to report suspected treatment failures?

They may indicate the development of antimicrobial resistance Signup and view all the answers

Which of the following best defines an antimicrobial agent?

Any substance that destroys or inhibits microorganisms Signup and view all the answers

What does broad-spectrum antimicrobials refer to?

Agents that have a wide range of activity against many organisms Signup and view all the answers

How can regular health checks benefit antimicrobial use?

They prevent the unnecessary use of antimicrobials Signup and view all the answers

What is the meaning of 'spectrum of activity' in relation to antimicrobials?

The variety of microorganisms that an antimicrobial can effectively target Signup and view all the answers

Antibiotics are defined as substances that what?

Are produced by one organism that selectively inhibit another organism Signup and view all the answers

What is an antimicrobial primarily defined as?

A substance that inhibits micro-organisms Signup and view all the answers

What does the term 'minimum inhibitory concentration' (MIC) refer to?

The lowest concentration of an antimicrobial that inhibits visible growth Signup and view all the answers

What differentiates a bactericidal from a bacteriostatic agent?

Bactericidal agents kill bacteria, while bacteriostatic agents inhibit their growth Signup and view all the answers

In veterinary medicine, what is the concept of empirical prescribing focused on?

Selecting treatment based on previous clinical experience and data Signup and view all the answers

What is a key concern associated with antimicrobial resistance (AMR)?

Results in a higher incidence of zoonoses and cross-species gene transfer Signup and view all the answers

Which of the following best describes the spectrum of activity of an antimicrobial?

The range of micro-organisms that the antimicrobial can inhibit or kill Signup and view all the answers

What is a characteristic of time-dependant modes of action in antimicrobials?

Duration above the MIC is crucial for effectiveness Signup and view all the answers

What distinguishes an antibiotic from an antimicrobial?

Antibiotics are produced by one organism to inhibit another, antimicrobials may not be Signup and view all the answers

What distinguishes concentration-dependent antimicrobials from time-dependent antimicrobials?

They achieve the highest dose in a short period. Signup and view all the answers

What is the primary concern regarding antimicrobial resistance?

It poses a significant threat to global health and food security. Signup and view all the answers

What does empirical prescribing involve?

Treating based on the most likely cause of disease without definitive tests. Signup and view all the answers

Which of the following correctly describes time-dependent antimicrobials?

They maintain drug levels above the MIC for an extended period. Signup and view all the answers

What are critically important antimicrobials?

Antimicrobials that are essential for treating serious bacterial infections. Signup and view all the answers

Which factor is NOT considered when determining whether a patient needs an antimicrobial?

The patient's history of allergies to medications. Signup and view all the answers

What is one of the objectives in discussing responsible antimicrobial use?

To minimize the risk of antimicrobial resistance in both humans and animals. Signup and view all the answers

What is the risk associated with bacteria that acquire resistance genes from non-human sources?

They may cause more severe infections in humans. Signup and view all the answers

How does the efficacy of a time-dependent antimicrobial relate to its exposure time?

Efficacy depends on the exposure time above the MIC. Signup and view all the answers

What does empirical prescribing involve in veterinary medicine?

Selecting a drug based on the most likely causative species. Signup and view all the answers

Which of the following strategies helps promote responsible antimicrobial use?

Regularly monitoring local sensitivity patterns. Signup and view all the answers

What is the primary concern related to antimicrobial resistance (AMR)?

It poses one of the greatest threats to modern medicine. Signup and view all the answers

What is a concentration-dependent antimicrobial's characteristic regarding bacterial cure?

Rapid bacterial cure results from high concentrations above the MIC. Signup and view all the answers

Which is NOT a recommended practice to combat antimicrobial resistance?

Using the same antibiotics repeatedly without assessing the infection. Signup and view all the answers

What is the typical duration for a course of a time-dependent antimicrobial?

5-7 days. Signup and view all the answers

Study Notes

Antimicrobials 1

Antimicrobials are substances that destroy or inhibit microorganisms (e.g., bacteria, viruses, protozoa).
Antibacterial agents are substances that specifically destroy or inhibit bacteria.
Antibiotics are substances produced by one organism that selectively destroy or inhibit the growth of another.
A significant misunderstanding is that some antimicrobials are "stronger" than others, as there is no such thing as a "strong" antimicrobial.
Each antimicrobial has a specific spectrum of activity against specific classes of microbes.
The recommended dose should always be prescribed, as under-dosing can drive the development of antimicrobial resistance.
The patient should complete the full course of antimicrobials even if the clinical signs have resolved to completely eradicate the infection.

Minimum Inhibitory Concentration (MIC)

The MIC is the lowest concentration of an antimicrobial drug that will inhibit visible growth of a microorganism after overnight incubation in vitro.
Clinical breakpoints are a modification of the MIC that take into account clinical data, including species, condition, route of administration, and antimicrobial mode of action (MoA).

Spectrum of Activity

Antimicrobials are described as broad-spectrum or narrow-spectrum based on the class(es) of organism they affect, for example, bacteria, protozoa, and viruses.
More commonly, broad-spectrum or narrow-spectrum refers to whether the antibacterial drug is effective against Gram-positive and/or Gram-negative bacteria.

Bactericidal vs Bacteriostatic

Bactericidal antibacterials kill bacteria.
Bacteriostatic antibacterials stop bacterial division.

Time-dependent Antimicrobials

The efficacy of a time-dependent antimicrobial is dependent on the exposure time above the minimum inhibitory concentration (MIC).
Increasing the dose will not enhance the effect.

Concentration-dependent Antimicrobials

The efficacy is dependent on the drug concentration above the MIC.
Increasing the dose reduces the bacterial count more rapidly.

Learning Objective 3 (Time-dependent vs Concentration-dependent)

Time-dependent drugs need to be above the MIC for a prolonged period.
Concentration-dependent drugs achieve maximum effect with high concentrations for a short time.

Learning Objective 4: Empirical Prescribing

Empirical prescribing means treating a disease based on the most likely cause in the absence of definitive tests.

Learning Objective 5: Antimicrobial Resistance and Responsible Use

Antimicrobial resistance (AMR) is a major threat to human health and global health.
Prescribing critically important antimicrobials should be avoided, with alternative treatments considered.
Use of a step-wise approach helps responsible use.
Avoid antibiotics if possible, selecting the correct antimicrobial, developing local protocols, monitoring local sensitivity, justifying deviations from protocols, and reporting suspected treatment failures are all part of responsible use.

Empirical Prescribing Steps

Does the patient need an antimicrobial?
Will prescribing an antimicrobial drug improve the prognosis?
What are the likely causative organisms?
Is there a risk of antimicrobial resistance (AMR)?
Consider taking microbiological samples before prescribing.
What is the narrowest spectrum of antimicrobial likely to be effective?
Benefits and harms for individual patients?
Consider other factors.
Present options to the client.

Responsible Use of Antimicrobials (7-Point Plan)

Work with clients to avoid need for antimicrobials.
Avoid inappropriate use (assess presence of bacteria and prognosis improvement).
Choose the right drug for the right bug (identify likely causative organisms, consider if Gram +/-, aerobic/anaerobic).
Monitor antimicrobial sensitivity (if possible, take sample and send for culture/sensitivity check; monitor local trends in sensitivity)
Minimise use (only use when necessary; consider reduction in morbidity/mortality; develop practice protocols).
Record and justify protocol deviations (keep good clinical records; explain chosen course of action).
Report suspected treatment failures to the VMD (this may be an early sign of resistance development).

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Description

This quiz covers essential concepts related to antimicrobials, including their definitions, classifications, and the importance of dosage. Understand the difference between bactericidal and bacteriostatic actions, along with the significance of Minimum Inhibitory Concentration (MIC) in antimicrobial therapy.