Indications for the use of highest priority critically important antimicrobials in the veterinary sector.

Background: Among the measures taken to preserve the clinical efficacy of highest priority critically important antimicrobials (HP-CIAs), the WHO has recommended avoiding their use in food-producing animals. Little is known regarding the indications for which different antimicrobial classes are used in animals, even in countries where data on antimicrobial use are available.

Objectives: To outline, in a narrative review, the diseases for which HP-CIAs are used in veterinary medicine, highlighting incongruences with international guidelines and disease conditions where effective alternatives to HP-CIAs are missing.

Methods: Scientific literature, national reports and expert opinion were used to describe the indications for the use of HP-CIAs in the main food-producing (pigs, cattle and poultry) and companion (horses, dogs and cats) animal species.

Results: The most common indications for use of HP-CIAs are enteric and respiratory infections in pigs, cattle and poultry, urogenital infections in dogs and cats and respiratory infections in horses. In some instances, no valid and convenient alternatives to colistin and macrolides are available against certain porcine enteric and bovine respiratory pathogens. Effective, legal and convenient alternatives to HP-CIAs are also lacking for managing common infections in cats, for which oral administration is difficult, Rhodococcus equi infections in horses, some enteric and respiratory infections in poultry and MDR infections in all companion animal species.

Conclusions: Future research and stewardship programmes should focus on the disease conditions identified by this review to reduce the use of HP-CIAs in the veterinary sector.