What is the recommended treatment for a urinary tract infection (UTI) caused by Gardnerella vaginalis in men?

Treatment of UTI Caused by Gardnerella vaginalis in Men

Metronidazole 500 mg orally twice daily for 7 days is the recommended treatment for urinary tract infections caused by Gardnerella vaginalis in men. 1, 2, 3

Understanding G. vaginalis UTIs in Men

Gardnerella vaginalis is primarily associated with bacterial vaginosis in women but can occasionally cause urinary tract infections in men. While uncommon, these infections can originate from the genitourinary tract and may present with typical UTI symptoms or even progress to bacteremia in some cases 4.

Treatment Regimen

First-line Treatment:

• Metronidazole 500 mg orally twice daily for 7 days 1, 2, 3
  • This regimen has been shown to be effective for G. vaginalis infections with clinical cure rates of approximately 92% 5
  • Patients should be advised to avoid alcohol during treatment and for 24 hours afterward to prevent disulfiram-like reactions 1, 2

Alternative Regimen:

• Ampicillin 2 g orally for 10 days 5
  • Similar efficacy to metronidazole (90% clinical and bacteriological cure rates)
  • May be better tolerated with fewer side effects than metronidazole 5

Special Considerations

1. Complicated UTIs: For men with complicated UTIs (which most male UTIs are considered to be), treatment duration should be extended to 14 days, especially when prostatitis cannot be excluded 1

2. Diagnostic Challenges:

   • Standard aerobic urine cultures may not detect G. vaginalis 4
   • Selective media should be used when G. vaginalis is suspected 6
   • Blood cultures with prolonged incubation may be necessary in cases of suspected bacteremia 4

3. Concurrent Infections:

   • Always evaluate for concurrent sexually transmitted infections, including Chlamydia trachomatis and Neisseria gonorrhoeae 1, 3
   • Testing for both gonorrhea and chlamydia is encouraged to facilitate partner referral and treatment 1

4. Partner Management:

   • Sexual partners should be evaluated and treated if the last sexual contact was within 30 days of symptom onset 1
   • Patients should abstain from sexual intercourse until both they and their partners complete treatment 2

Follow-Up

• Patients should return for evaluation if symptoms persist or recur after completion of therapy 1
• If symptoms persist without evidence of urethral inflammation, extending antimicrobial duration has not shown benefit 1
• For persistent or recurrent symptoms with confirmed infection, consider retreatment with the initial regimen if compliance was poor or re-exposure occurred 1

Treatment Failures

For persistent or recurrent urethritis after initial treatment:

1. Rule out reinfection or non-compliance
2. Consider alternative regimen:
   • Metronidazole 2 g orally in a single dose plus azithromycin 1 g orally in a single dose (if not used for initial episode) 1

Caution

• Persistent pain, discomfort, and irritative voiding symptoms beyond 3 months should raise suspicion for chronic prostatitis/chronic pelvic pain syndrome 1
• G. vaginalis bacteremia, while rare, has been reported in men with underlying comorbidities and may require parenteral therapy 4

G. vaginalis UTIs in men are uncommon but should be considered when standard cultures are negative despite symptoms of UTI, particularly in patients with urological abnormalities or following urological procedures 6.