Clinical Features of Mycoplasma Bacteriuria in Dogs and Cats

Abstract: Background—Mycoplasma bacteriuria has been rarely described in dogs and cats, and associated patient features have not been reported.
Objectives—To describe clinical features of mycoplasma bacteriuria in dogs and cats.
Animals—Client-owned dogs (n=58) and cats (n=4) with mycoplasma bacteriuria diagnosed at a veterinary teaching hospital (2010-2025).
Methods—Retrospective descriptive study. Medical records of dogs and cats with urine cultures performed were searched, and animals with mycoplasma bacteriuria were enrolled.
Results—Mycoplasma bacteriuria was identified in 70 urine samples submitted from 58 dogs; 39% of dogs were azotemic. Concurrent lower urinary tract disease was identified in 83% of dogs, including urothelial carcinoma (59%), other masses (7%), and urolithiasis (7%). Urinary tract implants were present in 13% of cases, including ureteral stents (6%), urethral stents (3%), and subcutaneous ureteral bypass (SUB) devices (4%). Urethral obstruction and upper urinary tract obstruction were present in 19% and 20% of dogs, respectively.
Mycoplasma bacteriuria was identified in 5 urine samples from 4 cats. All cats were azotemic at diagnosis, and 80% had SUB devices. None of the cats had lower urinary tract masses or urolithiasis.
Mycoplasma-directed antimicrobials were prescribed in 61% of dogs and 100% of cats.
Conclusions and Clinical Importance—In this cohort, mycoplasma bacteriuria was commonly associated with lower urinary tract neoplasia in dogs and SUB devices in cats. Mycoplasma species are intrinsically resistant to beta-lactam antibiotics commonly prescribed for empiric treatment of urinary tract infections. Given this, knowledge of mycoplasma-associated patient features may help optimize initial antimicrobial treatment.