Advancing standardization of diagnostics and antimicrobial susceptibility testing for pathogenic mycoplasmas of livestock origin: insights from the MyMIC network

Abstract

Mycoplasma infections pose a significant economic burden and represent a serious health and welfare concern for the livestock sector. Their control often requires repeated antimicrobial treatments. Antimicrobial susceptibility testing (AST) procedures for veterinary mycoplasmas lack standardization. Furthermore, clinical breakpoints (CBPs) are not available to interpret AST data (i.e., Minimum Inhibitory Concentration, MIC values) and categorize isolates as susceptible, resistant, or intermediate to the different antimicrobials used in livestock, nor epidemiological cut-offs (ECOFFs), which are a prerequisite to define CBPs. In 2023, the MyMIC network - a consortium of 22 laboratories specializing in veterinary mycoplasmas- was established to support efforts in standardizing diagnostics and AST, including clinical interpretation. Its initial goals were to (i) review routine diagnostic practices in frontline laboratories and examine veterinarians’ prescribing habits and (ii) assess practices for culture, identification and AST used in expert laboratories and how these practices may affect MIC results as collected for five major livestock pathogens (M. bovis, M. gallisepticum, M. synoviae, M. hyopneumoniae and M. hyorhinis).