Which test should I order to detect Ureaplasma infection?

Testing for Ureaplasma: Not Recommended in Routine Practice

Culture or NAATs for Ureaplasma is not recommended because of the high prevalence of colonization in asymptomatic, sexually active people. 1

Why Routine Ureaplasma Testing Should Be Avoided

The fundamental issue with Ureaplasma testing is that asymptomatic carriage is extremely common (40-80% of sexually active individuals), and the majority do not develop disease 2. This creates a clinical dilemma where positive results rarely indicate true infection requiring treatment.

Key Evidence Against Routine Testing

• Routine screening of asymptomatic men and women or routine testing of symptomatic individuals for M. hominis, U. urealyticum, and U. parvum is not recommended by the European STI Guidelines Editorial Board 2

• The role of Ureaplasma species in causing urethritis is debated, with recent data suggesting that only U. urealyticum (not U. parvum) may be an etiological agent in non-gonococcal urethritis, and likely only when present in high bacterial loads 1, 2

• At present, we have no evidence that we are doing more good than harm detecting and subsequently treating these organisms 2

Clinical Harms of Inappropriate Testing

The widespread use of Ureaplasma testing, particularly through commercial multiplex PCR panels, creates several problems:

• Selection of antimicrobial resistance in Ureaplasma species, true STI pathogens, and the general microbiota 2

• Substantial economic cost for society and individuals, particularly women 2

• Overtreatment of colonization rather than infection, exposing patients to unnecessary antibiotics without clinical benefit 2

When Testing Might Be Considered (Rare Circumstances)

If testing is undertaken in men with symptomatic urethritis, a specific algorithm must be followed:

1. First exclude traditional STI urethritis agents: Neisseria gonorrhoeae, Chlamydia trachomatis, M. genitalium, and (where relevant) Trichomonas vaginalis 2

2. Use quantitative species-specific molecular diagnostic tests (not culture) to distinguish U. urealyticum from U. parvum 2

3. Only consider treatment in men with high U. urealyticum load, though appropriate evidence for effective treatment regimens is lacking 2

Available Testing Methods (If Absolutely Necessary)

While not recommended for routine use, the following methods exist:

• PCR-based NAATs targeting the urease gene or 16S rRNA gene have sensitivity of 90-96% and specificity of 98-99% compared to culture 3, 4, 5

• Real-time PCR assays can detect and differentiate U. urealyticum from U. parvum, with sensitivity of 96.5% and specificity of 93.6% 4

• Quantitative PCR with biovar determination can identify bacterial load and distinguish biovar 1 from biovar 2 6

Special Populations

Women with Symptoms

• In symptomatic women, bacterial vaginosis should always be tested for and treated if detected before considering any Ureaplasma testing 2

• Ureaplasma testing in women is particularly problematic given the 40-80% colonization rate and lack of evidence linking detection to improved outcomes 2

Pregnant Women

• While not explicitly addressed in the guidelines provided, the general principle of avoiding routine Ureaplasma testing applies unless specific obstetric complications warrant investigation 2

Common Pitfalls to Avoid

• Do not order multiplex STI panels that include Ureaplasma without understanding that positive results will create management dilemmas 2

• Do not treat asymptomatic Ureaplasma colonization detected incidentally on testing performed for other reasons 1, 2

• Do not assume that Ureaplasma detection in symptomatic patients is causative without excluding other pathogens and confirming high bacterial load 2