The choice of antibiotic for treatment of acute bacterial prostatitis (ABP) is based on the results of the initial culture and sensitivity. However, initial therapy should be directed at gram-negative enteric bacteria. Useful agents include fluoroquinolones, trimethoprim-sulfamethoxazole, and ampicillin with gentamicin. If the initial clinical response to therapy is satisfactory and the pathogen is susceptible to the chosen antibiotic, treatment is continued orally (PO) for 30 days to prevent sequelae such as chronic bacterial prostatitis and prostatic abscess formation.