Urinary Tract Infection, Lower (Bacterial) in Dogs | PetMD

The invasion and colonization of bacteria in the urinary bladder and/or the upper portion of the urethra may result in infection when the local defense system, which helps protect against infection, is impaired. Symptoms related to this type of infection include inflammation of the affected tissue and urinary difficulties.

https://www.petmd.com/dog/conditions/urinary/c_dg_lower_urinary_tract_infection_bacterial