Common pathogens causing acute bacterial prostatitis and typical empiric therapy?

• A. Staphylococcus aureus
• B. Pseudomonas
• C. Enterococcus
• D. Enteric Gram-negative rods (e.g., E. coli); empiric antibiotics: fluoroquinolones or TMP-SMX; 4–6 weeks

Answer: (D)

Acute bacterial prostatitis is most commonly caused by enteric Gram-negative rods, especially Escherichia coli. That’s why empiric therapy targets these organisms and uses antibiotics that achieve good prostatic tissue penetration. Fluoroquinolones are a classic first-line choice because they penetrate the prostate well and are active against gram-negative rods, and trimethoprim-sulfamethoxazole also penetrates the prostate and covers many enteric pathogens. The infection is slow to clear from prostatic tissue, so a longer course—about 4 to 6 weeks—is recommended to ensure eradication. While Staphylococcus aureus and Enterococcus can be involved in certain scenarios (like catheter-associated or healthcare-associated infections), they’re not the typical organisms for uncomplicated acute prostatitis, and Pseudomonas concerns arise more in hospitalized or high-risk patients rather than the standard outpatient setting.