Asymmetric urinary lesions associated with Proteus mirabilis infection in a beef calf

An 8-mo-old Japanese Black beef heifer calf was presented with anorexia, dysuria, and abdominal pain. Ultrasonographically, the left renal pelvis and calyces were markedly dilated and contained numerous calculi; the right renal pelvis was filled with hyperechoic material without obvious calculi. Despite supportive care and antimicrobial treatment with ceftiofur, the calf died 4 d after presentation. Autopsy revealed severe hydronephrosis with numerous struvite calculi in the left kidney and advanced pyonephrosis in the right kidney. Proteus mirabilis was isolated antemortem from urine and postmortem from purulent material in both kidneys, ureters, urinary bladder, and an associated urachal remnant abscess. As found in our case, P. mirabilis infection in cattle can be associated with both obstructive and suppurative renal lesions within a single animal. Our case emphasizes the importance of comprehensive diagnostic investigation, including bilateral renal ultrasonography and thorough bacteriologic evaluation, and offers diagnostic insight into the variable pathologic manifestations of P. mirabilis-associated urinary tract disease in cattle.