Growth kinetics of Taylorella equigenitalis and its survival in straw-based bedding

Abstract Taylorella equigenitalis , the causative agent of contagious equine metritis, is a fastidious bacterium with limited tolerance to extra-host conditions; however, quantitative data on its growth dynamics and survival outside the host remain scarce. This study evaluated the growth of T. equigenitalis under aerobic and microaerophilic conditions in liquid medium and its survival in wet and dry straw-based bedding under controlled laboratory conditions. Growth was assessed at 20 °C and 37 °C using real-time optical density monitoring and viable cell counts. No proliferation was observed at 20 °C, whereas incubation at 37 °C resulted in measurable growth after 25–33 h. Viable cell counts were higher after incubation under aerobic conditions than under microaerophilic conditions, with a mean difference of 0.45 log 10 . Bacterial survival in straw-based bedding declined progressively over seven days, with significantly higher counts maintained under wet conditions compared to dry conditions. Viable cells remained detectable until the end of the experiment, particularly in wet bedding. The results provide quantitative data on the growth characteristics of T. equigenitalis and underscore the importance of appropriate hygiene and biosecurity measures in equine breeding facilities.