Screening for antimicrobial resistant bacteria in cooled stallion semen and post-insemination uterine lavage fluid

The study aimed to evaluate the presence of antimicrobial resistance (AMR) in cooled semen and post-insemination uterine lavage fluid. The study involved cultured samples from commercial domestic or international cooled semen shipments, and analyzed for bacterial growth on blood agars, selective media, and uterine lavage fluid. Results showed that 23% of semen samples showed bacterial growth, while 21%, 17%, 14%, and 9% of samples showed bacterial growth on selective media. Most mare and semen samples had no bacterial growth. Resistant strains, such as ESBL and AmpC-producing Enterobacter cloacae and VRE, may present health risks, including zoonotic spread of AMR. The study concluded that while bacteria may be present in cooled stallion semen, they are not necessarily found in the uteri of inseminated mares, as uterine defense mechanisms in normal mares may clear bacteria effectively.