LAUSR

Abstract Background Lameness is an economically important and common disease of cattle, and foot disease is the most common cause of lameness in cattle. Limited data is available regarding lameness in cow‐calf operations. Objectives Describe the bacteria most commonly isolated from septic lesions of the feet of adult beef cattle and the antimicrobial susceptibility patterns of the isolated bacteria. Animals Fifty‐four adult cattle from cow‐calf operations and diagnosed with a sole abscess or distal interphalangeal joint sepsis were enrolled. Methods Prospective observational study. Abscess fluid from a convenience sample of clinical cases was cultured. Isolated bacteria were identified using matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry or 16s rRNA gene sequencing. Antimicrobial susceptibility profiling was performed on isolates when a bacterial species was identified from ≥5 samples. Results Fifty of the 54 samples were polymicrobial. Trueperella pyogenes (22/54), Streptococcus uberis (16/54), and Bacteroides pyogenes (14/54) were the most commonly isolated bacteria. Eighty‐one of 96 tested isolates were resistant to at least 1 antimicrobial; multidrug resistance was identified in 37/96 isolates. Oxytetracycline (50/96), tylosin (40/96), and florfenicol (37/96) resistance was commonly identified. Resistance to ceftiofur (5/96) was rare. Conclusions and Clinical Importance Septic processes of the foot in these adult beef cattle frequently were polymicrobial. Most of the isolated bacteria were resistant to at least 1 antimicrobial with over one‐third being multidrug resistant. Although simple sole abscesses do not require antimicrobial treatment, deep septic processes of the foot often are treated with antimicrobials. Culture and susceptibility of deep septic lesions may guide judicious antimicrobial usage.