Emerging Human Pathogen <em>Sphingomonas paucimobilis</em> Associated with Tongue Lesions in a Group of Crossbred Beef × Dairy Bulls Prior to Slaughter

Sphingomonas spp. are ubiquitously distributed free-living microorganisms in the natural environment. One of the representatives of the family called Sphingomonas paucimobilis is known as an opportunistic pathogen in humans responsible for bone and soft tissue infections. In January 2024, signs of drooling, tongue rolling and local oedema in the pharyngeal region were observed in a male beef-dairy cross. Clinical examination revealed several ulcerative lesions on the tongue. The bull was not treated with antibiotics due to the impending slaughter of the entire lot of cattle. During the slaughter of 14 dairy-beef bulls, it was found that 13 of them had necrotic ulcerative lesions on the dorsal surface of the tongue. Bacteriological studies conducted on tongue samples from two of the bulls successfully isolated and identified a strain of Sphingomonas paucimobilis. Increasing reports of this organism highlight its potential as a pathogen in animals, with possible health and economic implications for livestock production. In addition, Sphingomonas spp. have been reported to have reduced susceptibility to several classes of antimicrobial agents, and some species exhibit inherent resistance to agents such as colistin/polymyxins. Although the clinical significance of resistance in veterinary isolates remains poorly understood, the combination of ubiquity in the environment, opportunistic pathogenicity, and variable antimicrobial susceptibility underscores the need for continued surveillance and careful interpretation of susceptibility results. Addressing these concerns is crucial for protecting both human and animal health.