Bacterial prostatitis is a common prostate disease in sexually intact male dogs; it may also occur in sexually intact male cats. It can develop as an acutely fulminating systemic disorder or, most commonly, as a chronic problem associated with recurrent urinary tract infections (UTIs).
Care should be taken when rectally palpating an acutely infected prostate, because septicemia or endotoxemia can occur. Most sexually intact male dogs with UTI also have infectious prostatitis.
The prostate gland differs from the rest of the urinary tract; its acidity leads to a decreasing pH gradient from the blood through the tissue to the acinar glands. The distribution of antimicrobials in the prostatic tissue, as well as in the prostatic secretions, depends on the local pH and the dissociation constant (pKa) of the drugs. For alkaline drugs, a large amount of ionic trapping leads to high antimicrobial concentrations in the tissue and secretions. In contrast, acidic drugs such as the beta-lactam antimicrobials do not reach concentrations equivalent to plasma concentrations.
The choice of antimicrobial to treat bacterial prostatitis should be based on culture and susceptibility results, and on the ability of the drug to penetrate the blood-prostate barrier. Ideal antimicrobials are highly lipid soluble, basic, and not highly protein bound. Fluoroquinolones are the best empirical choice for E coli infections; chloramphenicol, doxycycline, or trimethoprim-sulfas can otherwise be considered, depending on the results of culture and susceptibility testing.
Antimicrobial treatment may need to be continued for up to 2 months, which may promote the emergence of antimicrobial resistance. Chronic bacterial prostatitis may be difficult to cure. Neutering the dog may increase the likelihood of successful treatment and prevent recurrence.
