What is infectious prostatitis?

What is Infectious Prostatitis?

Infectious prostatitis is a bacterial infection and inflammation of the prostate gland that presents in two distinct forms: acute bacterial prostatitis (a febrile urinary tract infection with prostatic involvement) and chronic bacterial prostatitis (a persistent prostatic infection causing recurrent UTIs from the same bacterial strain). 1, 2

Epidemiology and Bacterial Causes

Prostatitis affects approximately 9.3% of men in their lifetime, though fewer than 10% of all prostatitis cases are confirmed to have bacterial infection. 1, 2

Acute bacterial prostatitis:

• Gram-negative bacteria cause 80-97% of cases, with Escherichia coli being the most common pathogen 1, 2
• Other gram-negative organisms include Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Enterobacter species, and Serratia marcescens 1
• Gram-positive bacteria (Staphylococcus aureus, Enterococcus species, Group B streptococci) account for the remaining cases 1

Chronic bacterial prostatitis:

• Up to 74% of cases are due to gram-negative organisms, particularly E. coli 1
• The same spectrum of pathogens as acute prostatitis can be responsible 1

Clinical Presentation

Acute bacterial prostatitis presents with:

• Pelvic pain and urinary tract symptoms (dysuria, urinary frequency, urinary retention) 2, 3
• Systemic symptoms including fever, chills, nausea, emesis, and malaise 2, 3
• Tender, enlarged, or boggy prostate on gentle digital rectal examination 3

Chronic bacterial prostatitis presents with:

• Recurrent urinary tract infections from the same bacterial strain 2, 4
• Pelvic pain, urinary symptoms, and ejaculatory pain 1, 5
• Subacute course without the severe systemic symptoms of acute infection 6

Diagnostic Approach

For acute bacterial prostatitis:

• Perform gentle digital rectal examination only—avoid vigorous prostatic massage or vigorous DRE due to risk of bacteremia 1
• Obtain midstream urine culture to identify causative organisms 1, 3
• Collect blood cultures, especially in febrile patients 1
• Check complete blood count to assess for leukocytosis 1
• Consider transrectal ultrasound in selected cases to rule out prostatic abscess 1

For chronic bacterial prostatitis:

• The Meares-Stamey 4-glass test is the gold standard: collect first-void urine, midstream urine, expressed prostatic secretions (EPS), and post-massage urine 7, 1, 4
• A positive result requires a 10-fold higher bacterial count in the EPS compared to midstream urine 7, 1
• A simplified 2-specimen variant (midstream urine and EPS only) can be used 7, 1
• Perform Gram stain or cell counts and aerobic culture of specimens 7, 1

Common diagnostic pitfall: Prostatic massage is contraindicated in acute prostatitis but is essential for diagnosing chronic bacterial prostatitis. 1

Treatment Principles

Acute bacterial prostatitis:

• First-line therapy is broad-spectrum intravenous or oral antibiotics targeting common uropathogens 2, 3
• Options include IV piperacillin-tazobactam, ceftriaxone, or oral ciprofloxacin with 92-97% success rate 2
• Treatment duration is 2-4 weeks 1, 2
• Assess clinical response after 48-72 hours 1
• Avoid amoxicillin or ampicillin empirically due to very high worldwide resistance rates 1

Chronic bacterial prostatitis:

• First-line therapy is a minimum 4-week course of fluoroquinolones (levofloxacin or ciprofloxacin) 2, 4
• Alternative agents include trimethoprim-sulfamethoxazole or doxycycline if the pathogen is susceptible 4
• Treatment may require 6-12 weeks for complete eradication 4, 6
• Stopping antibiotics prematurely can lead to chronic bacterial prostatitis 1

Key Distinction from Non-Infectious Prostatitis

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is not frequently caused by a culturable infectious agent and requires different management focused on symptom relief rather than antimicrobials. 7, 2