While antibiotics are essential medicines for treating bacterial infections, it is important to remember that their use leads to selection of resistant strains of bacteria. It is important that veterinarians use antibiotics responsibly to:

• Minimize the selection of resistant veterinary pathogens to safeguard animal health
• Minimize possible transfer of resistance determinants to human pathogens
• Retain the right to prescribe certain antibiotics.

Following these guidelines will help to maximize therapeutic success of antibacterial agents while minimizing the development of antibiotic resistance, conserving antimicrobials for future veterinary and human use. Individual drug monographs for all antimicrobials should be read in conjunctio with updated BSAVA Guide to the Use of Veterinary Medicines and the PROTECT ME guidance (www.bsavalibrary.com).

Following the PROTECT ME guidance can help reduce resistance:

PRESCRIBE ONLY WHEN NECESSARY

• Consider non-bacterial disease (e.g. viral infection, nutritional imbalance or metabolic disorders).
• Some bacterial diseases will self-resolve without antibiotics.
• Offer a non-prescription form.
• Perioperative antibiotics are NOT a substitute for surgical asespsis.

REPLACE WITH NON-ANTIBIOTIC TREATMENTS

• Lavage and debridement of infected material, fluid therapy, diteary management, cough suppressants and measures to address underlying conditions may negate the need for antibiotics.
• Use topical preparations (ideally antiseptics) where possible to reduce selection pressure on intestinal flora (the microbiome).

OPTIMIZE DOSAGE PROTOCOLS

• Use the shortest effective course and avoid underdosing.
• Treat until clinical resolution.

TREAT EFFECTIVELY

• Consider which bacteria are likely to be involved.
• Consider drug penetration of the target site (e.g. drug selection for prostatitis, osteomyelitis).
• Consider pharmacokinetics and drug interactions with concurrent medication.
• Provide instructions, including demonstrations, on how to administer prescribed antibiotics.

EMPLOY NARROW SPECTRUM AND AVOID ANTIBIOTIC COMBINATION THERAPY

• Use narrow spectrum, rather than broad-spectrum, antibiotics to minimize resistance.
• Use culture results to support de-escalation (switch to a narrower spectrum antibiotic).

CYTOLOGY AND CULTURE GUIDES PRESCRIBING DECISIONS

• Use cytology to demonstrate bacterial involvement AND an inflammatory response consistent with infection (e.g. intracellular bacteria).
• Collect a sample for culture before starting antibiotic therapy wherever possible.
• Culture is essential when using prolonged (>1 week) treatment courses, where there are risk factors for resistance (e.g. healthcare-acquired infections, antibiotic treatment in the prior 60 days or multiple prior courses/repeated antibiotic use), AND in life-threatening situations.

TAILOR YOUR PRACTICE POLICY

• Discuss your practice's first-line antibiotic choice for each condition with your colleagues, complete the tick boxes in the PROTECT ME poster and display it so your protocols are clear, including when the approach is to NOT prescribe an antibiotic.
• Evaluate practice biosecurity and hand hygeine practices.
• Practice preventative medicine (vaccination, parasite prevention) to prevent infections and unnecessary antibiotic use.

MONITOR

• Monitor for preventable infections (e.g. surgical site infections) and alter practice protocols if needed.
• Audit your own antibiotic use, particularly of EMA Restric category antibiotics (fluroquinolones/3rd generation cephalosporins) e.g. using RCVS Knowledge tool.

EDUCATE OTHERS

• Promote awareness of AMR among staff and clients (see full PROTECT ME guide).
• Encourage return of leftover antibiotics for safe disposal.

EUROPEAN MEDICINES AGENCY CATEGORIZATION OF ANTIBIOTICS

In 2019, the EMA launched a public consultation on its updated scientific advice on the categorization of antibiotics. The scientific advice ranks antibiotics by considering both the risk that their use in animals causes to public health through the possible development of antimicrobial resistance, and the need to use them in veterinary medicine. It now addresses all classes of antibiotics, including those classified as critically important antimicrobials for human health by the World Health Organization (see Useful websites).

Readers are encouraged to check and consider the EMA’s updated scientific advice on the categorization of antibiotics when prescribing these medicines for animals in their care. The categorization can also be used as a tool for the preparation of treatment guidelines (see Useful websites). The classification comprises four categories:

• Category A (Avoid) includes antibiotics that are currently not authorized in veterinary medicine in the European Union (EU). These medicines may not be used in food-producing animals and may be given to individual companion animals only under exceptional circumstances
• Category B (Restrict) refers to fluroquinolones, 3rd and 4th generation cephalosporins and polymyxins. Antibiotics in this category are critically important in human medicine and their use in animals should be restricted to mitigate the risk to public health
• Category C (Caution) covers antibiotics for which alternatives in human medicine generally exist in the EU, but only few alternatives are available in certain veterinary indications. These antibiotics should only be used when there are no antibiotic substances in Category D that would be clinically effective
• Category D (Prudence) includes antibiotics that should be used as first line treatments, whenever possible. These antibiotics can be used in animals in a prudent manner. This means that unnecessary use and long treatment periods should be avoided, and group treatment should be restricted to situations where individual treatment is not feasible.

ANTIBIOTICS IN SMALL MAMMALS

Antibiotic therapy in several small mammal species poses a greater risk when compared with other species due to the suppression of normal bacterial flora, resulting in overgrowth of other species, notably Clostridium, resulting in enterotoxaemia and death. Mice, rats, ferrets and usually gerbils are fairly resistant, whereas hamsters, guinea pigs, chinchillas, degus and rabbits are more susceptible. The risk of enterotoxaemia is related to several factors, including the drug selected, the dose, the route of administration and the animal’s nutritional status and general health. Antibiotics that have been associated with this problem when given orally include penicillins, lincosamides, cephalosporins and erythromycin. Some species appear more sensitive to certain drugs than others, while some medications appear well tolerated by alternative routes (e.g. injectable benzylpenicillin in rabbits). See individual monographs for more details.

REFERENCES

Allerton F and Nuttall T (2021) Antimicrobial use: importance of bacterial culture and susceptibility testing. In Practice 43, 500–510 Sykes J and Greene J (2011) Infectious Diseases of the Dog and Cat, 4th edn. Saunders, Philadelphia

RCVS Knowledge (2026) Antibiotic Audit. Available from: knowledge.rcvs.org.uk/amr/vetteamamr/amr-audit.

Sykes J and Greene J (2011) Infectious Diseases of the Dog and Cat, 4th edn. Saunders, Philadelphia