WHAT ARE THE FACTORS THAT AFFECT “ANTIBIOTIC RANK”?

Factors Influencing the Ranking of Veterinary Antibiotics

1. Resistance Potential

One of the most critical factors in ranking veterinary antibiotics is their potential to promote antibiotic resistance. Drugs like fluoroquinolones and third-generation cephalosporins are closely monitored because of the risk that resistant strains can transfer from animals to humans through food consumption or direct contact.

2. Spectrum of Activity

Broad-spectrum antibiotics are generally ranked higher due to their ability to treat a wide variety of infections. However, overuse of these antibiotics increases the risk of resistance, so a balance must be struck between effectiveness and stewardship.

3. Regulatory Guidelines

Global health organizations such as the WHO and the Food and Agriculture Organization (FAO) rank antibiotics based on their importance to human medicine, providing guidance on their use in animals. Critically important antibiotics are subject to more stringent regulations to limit the spread of resistance.

4. Safety Profile

The safety of an antibiotic is also a key factor. Drugs with severe side effects, such as aminoglycosides, are used sparingly despite their effectiveness, especially in companion animals.

Other factors to consider:

The route of administration should be taken into account alongside the categorization when prescribing antibiotics. The list below suggests routes of administration and types of formulation ranked from the lowest to the highest estimated impact on antibiotic resistance.

1. Local individual treatment (e.g., udder injector, eye or ear drops)
2. Parenteral individual treatment (intravenously, intramuscularly, subcutaneously)
3. Oral individual treatment (i.e., tablets, oral bolus)
4. Injectable group medication
5. Oral group medication via drinking water/milk replacer
6. Oral group medication via feed or premixes

Source:

1. Guidance for the rational use of antimicrobials (https://www.ava.com.au/siteassets/advocacy/gram-book—guidance-for-the-rational-use-of-antimicrobials.pdf)
2. AMEG – EMA’s Antimicrobial Advice Ad Hoc Expert Group Report

(https://www.ema.europa.eu/en/documents/report/categorisation-antibiotics-european-union-answer-request-european-commission-updating-scientific-advice-impact-public-health-and-animal-health-use-antibiotics-animals_en.pdf)

OIE LIST OF ANTIMICROBIAL AGENTS OF VETERINARY IMPORTANCE (https://www.woah.org/app/uploads/2021/06/a-oie-list-antimicrobials-june2021.pdf)