Antimicrobials

Question 1

What is the Relative Contribution of Therapeutic Use of Antimicrobials in Animals to Resistance among Human Pathogens?

Answer 1

Strong evidence that antimicrobial use in animals can promote resistance in some zoonotic pathogens

Data are not conclusive regarding the impact on AMR in human pathogens.

Question 2

T/F: Most human AMR isolates have originated from animal species.

Answer 2

F: Antimicrobial use in a single animal species is the main force behind development of AMR in bacteria infecting or colonizing that species,

Question 3

Does Therapeutic Antimicrobial Use (Prudent or Otherwise) in Humans Contributes to Resistance Among Animal Pathogens?

Answer 3

Direct evidence is often lacking

Circumstantial evidence indicating human origin, human-to-animal, or both modalities of transmission of some antimicrobial resistant pathogens, particularly in horses and household pet (but also in livestock).

potential for further transmission back to humans or to other animals.

Question 4

Does Therapeutic Antimicrobial Use (Prudent or Otherwise) in Animals Contribute to Resistance Among Animal Pathogens?

Answer 4

Some data indicate that it does, but relatively little literature exists, particularly regarding specific drugs and drug classes that produce the greatest risk.

Question 5

Give an in horses where therapeutic antimicrobial has lead to antimicrobial resistance in that pathogen.

Answer 5

○ R. equi in foals- resistance has been increasing over the last 10 years (in macrolides)

foals infected with resistant isolates are more likely to die than foals infected with susceptible isolates

Question 6

What is the effect of antimicrobial use on the development of resistance in the intestinal microbiota?

Answer 6

More information is needed
cefotaxime-resistant or cefovecin-resistant faecal E. coli strains in dogs treated with cephalexin or cefovecin.

Question 7

Are MDR Pathogens More Virulent than their Susceptible Counterparts?

Answer 7

Most infections caused by MDR pathogens should be no more virulent than those caused by their susceptible counterparts if the resistant pathogen is promptly identified and appropriate antimicrobial therapy is initiated.

* Discrepancies in outcomes are often related to ineffective initial antibiotic therapy (empirical), leading to a delay in infection control, rather than increased virulence of resistant organisms

Question 8

Give the 3 main goals when limiting AMR

Answer 8

prevent disease occurrence
reduce overall antimicrobial drug use
improved antimicrobial use

Question 9

Give 4 means of preventing disease

Answer 9

• Involves:
  
  • Good animal care and husbandry practices.
  • Appropriate use of efficacious vaccines.
  • Implementation of infection control measures in veterinary hospitals and on farms.
  • Basic disease prevention and control approaches.

Question 10

Give 3 means of optimising antimicrobial drug use:

Answer 10

Choosing appropriate antimicrobials based on susceptibility testing.

Administering antimicrobials at correct dosages and durations.

Avoiding unnecessary or inappropriate use of antimicrobials

Question 11

Give an example of situations hwere a tailored treatment approach may be mopre appropriate than systemic antimicrobals.

Answer 11

Localized abscesses are best treated with incision and drainage, with no evidence supporting the need for concurrent antimicrobial therapy.
Local therapy with biocides or antimicrobial drugs may be equally or more effective in some cases, such as chlorhexidine bathing for superficial folliculitis in dogs.

Question 11

Should Access to Some Antimicrobials be Restricted?

Answer 11

The Committee supports the recommendation that all antimicrobials (excluding ionophores) intended for use in animals should be available only by prescription from a veterinarian with a valid veterinarian/client/patient relationship.

The Committee advocates for a cautious approach to antimicrobial use in animals, emphasizing the need to consider various factors and unintended consequences.
Voluntary restriction is preferred, allowing for regionally relevant approaches balancing animal care and resistance concerns.

Excluding antimicrobials from the World Health Organization’s list of critically important antimicrobials is impractical as it encompasses most clinically used antimicrobials.

Question 11

Is On-label Use Equivalent to Prudent Use?

Answer 11

Label information for older drugs may not reflect current principles of antimicrobial drug use and may be based on outdated evidence.
* Example: Procaine penicillin is often administered at a dose lower than current recommendations, based on outdated label information.

Newer drugs approved for narrow indications, like fluoroquinolones and later generation cephalosporins, possess broad-spectrum activity and can impact the microbiota significantly.

Question 11

Give 3 examples of compounding drugs

Answer 11

Mixing two approved drugs.
Preparing oral pastes or suspensions from crushed tablets.
Adding flavoring to approved drugs.

Question 11

Can antimicrobials be compounded for food producing animals?

Answer 11

No

Question 11

Give 4 concerns with compounding antimicrobials

Answer 11

Uncertain pharmacokinetic profiles, stability, potency, and safety.

Compounded products may not meet mandated potency ranges or exhibit inadequate bioequivalence compared to brand name products.

Stability issues may arise, leading to degradation or variation in drug concentration over time.

Administration of sub-therapeutic doses or overdosing may occur, potentially increasing antimicrobial resistance or causing adverse effects

Question 11

T/F: Generic antimicrobial preparations are less effective.

Answer 11

F: Similar efficacy is expected between generic and brand-name drugs.
Manufacturers of generic drugs are not required to replicate safety and efficacy studies conducted for brand-name drugs.

Question 12

Should Diagnostic Laboratories Test and Withhold Culture and Susceptibility Results for Certain Antimicrobial Drugs or Isolates?

Answer 12

The Committee supports selective reporting as a measure to optimize animal care and promote antimicrobial stewardship

Question 13

3 advantages of in house culture

Answer 13

Shorter turnaround time, less chance of viability loss during storage and shipping, and potentially lower costs compared to external laboratories.

Question 14

What is the main disadvantage of in house culture?

Answer 14

limitations in specificity and accuracy

Question 15

Clinics must comply with containment level ??/biosafety level ?? protocols if performing culture

Answer 15

2

Question 16

What is the basis of de-escalation of antimicrobial therapy?

Answer 16

In life-threatening conditions such as sepsis, broad-spectrum antimicrobials may be necessary initially.

Transition to more targeted treatment should be attempted based on culture and susceptibility testing results, additional diagnostic information, and clinical progression.

Before adding antimicrobials to an animal’s regimen, consideration should be given to whether the currently administered antimicrobials should be discontinued.

Question 17

T/F: Antimicrobials should be administered for the entireity of their minimum efficacious course.

Answer 17

F: * There is limited evidence to guide the duration of antimicrobial therapy in animals.
* Recommendations from clinical guidelines and review articles have limited scientific foundation.
* Properly designed randomized clinical trials are needed to provide guidance on the optimal duration of therapy.

Question 18

T/F: Shorter courses of antimicrobials promote resistance.

Answer 18

F: * Shorter durations reduce exposure of commensal bacterial populations to antimicrobials.
They are associated with improved client compliance, reduced costs, and reduced likelihood of adverse drug effects.

There is a common misconception that completing a minimum duration of antimicrobial therapy is necessary to prevent the emergence of resistance

Question 19

T/F: Periodic antimicrobial treatment is recommended in order to prophylactically prevent infection.

Answer 19

F: * There is a lack of strong evidence supporting the efficacy of prophylactic antimicrobial therapy in animals.
* The Committee discourages these approaches due to:
* Failure to adhere to sound pharmacokinetic-pharmacodynamic (PK-PD) concepts.
* Lack of evidence regarding efficacy or impact on antimicrobial resistance.

Question 20

Give 3 other properties of antimicrobials (other than antibacterial).

Answer 20

Anti-inflammatory.
Immunomodulatory.
Prokinetic.

Question 21

The Committee does not/does not support antimicrobial use for non-antimicrobial effects use for these effects.

Answer 21

Does not: The clinical relevance of these nonantimicrobial effects is poorly understood.
* There is a lack of compelling evidence regarding their efficacy.
* Data regarding potential adverse effects are also lacking.

Question 22

Regular screening cultures are/are not recommended in order to prevent bacterial infections.

Answer 22

Are not: * Principle of “Knowing Less Leads to Doing Less”: less unnecessary testing leads to less unnecessary antimicrobial use

Culture of sites usually colonized by commensal organisms, where clinical interpretation of results is difficult, is not recommended

Question 23

T/F: Unused antimicrobials may be disposed of in normal waste.

Answer 23

F: should return to practice: prevents future inappropriate use by client.

Question 24

What factors should be considered when assigning an antimicrobial a ‘tier’?

Answer 24

spectrum of activity, activity of the drug at commensal microbiota sites, likelihood of resistance emergence and importance of the drug for treatment of serious infections in humans and animal

Question 25

List 5 key features of antimicrobial stewardship

Answer 25

Question 26

In foals with sepsis, does the initial ‘correct’ empirical antimicrobial choice actually make a difference to survival?

Answer 26

Yes, p=0.04, 65% vs 45% survival correct vs incorrect

Question 27

2 methods of antimicrobial susceptibility testing

Answer 27

disk diffusion: Kirby Bauer disks: gives S/I/R
microdilution: gives MIC and S/I/R

Question 28

T/F: antimicrobial breakpoints are fixed and do not change.

Answer 28

F: vary with time! Important when reading studies

Question 29

What is the most common pathogen in foal sepsis?

Answer 29

E. coli (11-31%)
Gram positive sepsis is increasing.

Question 30

T/F: foal sepsis is only caused by 1 bacteria at a time?

Answer 30

F: 8-45% polymicrobic infections- is associated with reduced survival

Question 31

Theelen et al 2020: Foals before and after 48 hours hospitalisation, blood cultures

Answer 31

Question 32

Theelen et al 2020: Foals before and after 48 hours hospitalisation, blood cultures

Answer 32

Question 33

What is the effect on hospitalisaton on neonatal blood culture results

Answer 33

Different species, and significantly less susceptible to all AMRs- unpredictable! Therefore should repeat blood cultures.

~3% were initially resistant to treatment
~5% acquired resistance
~6% not eliminated despite being susceptible= treatment failures.
~85% potentially healthcare associated infections

Question 34

What % of septic foals may be expected to have a negative BC on day 0 but positive on day 2?

Answer 34

85%!!!!