Veterinary antimicrobials practices for swine mycoplasmoses: a field survey and comparison with scientific and regulatory recommendations

Abstract

Mycoplasma infections pose a significant challenge in swine production because of their economic impact and the difficulties associated with diagnosis and treatment. Antimicrobials are often the only available option for combating mycoplasmoses despite reports of resistance to several molecules and the frequent chronic nature of infections, which can reduce treatment efficacy. This study aimed to investigate the use of antimicrobials against swine mycoplasmoses through an international field survey and to review the relevant scientific literature and regulatory recommendations. The survey was led by the MyMIC network, whose main objective is to standardise antimicrobial susceptibility testing (AST) methods for livestock mycoplasmas. The responses of 118 swine veterinarians across 25 countries were analysed. No significant variations in practices were observed between countries. Macrolides, tetracyclines, and pleuromutilins were the most prescribed antimicrobial classes (used in more than 40%, 20% and 5% of clinical cases, respectively), which is consistent with current recommendations. Additional diagnosis with laboratory-based methods was commonly reported, with only 2.5% of veterinarians indicating that they never used it. However, AST was not commonly performed; only 30% of respondents reported requesting it in more than half of the cases. Ineffective or critically important antibiotics, such as beta-lactams or fluoroquinolones, were occasionally prescribed (approximately 1% for each). Occasional deviations from the recommended dosages were also noted. These findings raise concerns regarding resistance selection and potential treatment failures. Our results underscore the need for enhanced diagnosis, especially AST, and for a wider dissemination and adoption of treatment guidelines to support the sustainable management of swine health. By developing and promoting harmonised AST protocols and enabling objective, data-driven prescriptions, MyMIC plays a key role in strengthening communication between swine veterinarians and diagnostic laboratories, thereby supporting international antimicrobial stewardship.