What are the next steps for a male patient with persistent symptoms and a negative urethral swab PCR test result for Trichomonas?

Management of Male Patients with Persistent Symptoms and Negative Urethral Swab PCR for Trichomonas

For men with persistent urethritis symptoms and a negative urethral swab PCR for Trichomonas, you should test additional specimen types (first-void urine and/or semen) using PCR or culture, as urethral swabs alone miss the majority of T. vaginalis infections in men. 1

Why Additional Testing is Critical

• Urethral swabs detect only 22.5% of T. vaginalis infections in men, while PCR on multiple specimen types detects 98.0% of cases 1
• Culture of urethral swabs alone is particularly insensitive—reliable detection requires testing multiple specimen types including first-void urine and semen 1
• Even with sensitive PCR assays, the majority of male partners require multiple specimens for reliable detection 1
• First-catch urine PCR-ELISA demonstrates 92.7% sensitivity and 95.2% adjusted specificity compared to culture, making it an excellent non-invasive option when urethral swabs are negative 2

Specific Testing Algorithm

Before pursuing additional Trichomonas testing, confirm objective signs of urethritis are still present:

• Mucopurulent or purulent urethral discharge, OR
• Positive leukocyte esterase test on first-void urine, OR
• ≥10 WBC per high-power field on microscopic examination of first-void urine sediment 3, 4

If objective signs persist with negative urethral swab:

1. Obtain first-void urine for T. vaginalis PCR or culture 5, 1
2. Consider semen specimen for PCR or culture (detects additional cases missed by urine alone) 5, 1
3. Rule out non-compliance with initial treatment or re-exposure to untreated partner 3, 4

Treatment for Confirmed Trichomonas

If additional testing confirms T. vaginalis:

• Metronidazole 2g orally in a single dose is FDA-approved for symptomatic trichomoniasis in males 6
• However, single-dose therapy has a 42.9% failure rate in men, while metronidazole 400mg three times daily for 5 days achieves 100% cure rate 7
• The FDA label also describes a 7-day regimen: 250mg three times daily for 7 consecutive days, which may minimize reinfection and provide higher cure rates 6

Treatment for Persistent Urethritis with Negative Trichomonas Testing

If all Trichomonas testing remains negative but objective urethritis persists:

• Treat for persistent/recurrent urethritis with metronidazole 2g orally in a single dose (or tinidazole 2g single dose) PLUS azithromycin 1g orally in a single dose if not used for initial episode 3, 4
• This combination addresses T. vaginalis (which may still be present despite negative testing) and Mycoplasma genitalium, a common cause of persistent urethritis 3, 4

Critical Partner Management

• All sex partners within the preceding 60 days must be evaluated and treated simultaneously, as asymptomatic male carriers are difficult to detect and negative cultures cannot be relied upon 6
• There is considerable difficulty isolating T. vaginalis from asymptomatic male carriers—negative smears and cultures are unreliable in this regard 6
• Partners should receive treatment effective against both Chlamydia and Trichomonas regardless of testing results 3, 4
• Both patient and partners must abstain from sexual intercourse for 7 days after treatment initiation and until symptoms resolve 3

Common Pitfalls to Avoid

• Do not rely solely on urethral swab testing—this misses approximately 75% of male T. vaginalis infections 1
• Do not retreat based on symptoms alone without objective signs of urethritis—this leads to unnecessary antibiotic exposure 3, 4
• Do not use single-dose metronidazole regimens in men—the failure rate is unacceptably high at 42.9% compared to multi-day regimens 7
• Do not assume negative testing rules out infection—even sensitive PCR requires multiple specimen types for reliable detection 1