What is Ureaplasma?

Ureaplasma: Clinical Significance and Management

Ureaplasma is a genus of bacteria comprising two human-associated species: Ureaplasma urealyticum and Ureaplasma parvum, which are among the most prevalent genital mycoplasmas isolated from the urogenital tract of both men and women. Certain strains of Ureaplasma, particularly Ureaplasma urealyticum, are associated with male infertility, nongonococcal urethritis, and other urogenital infections, while Ureaplasma parvum appears to have less pathogenic potential. 1

Microbiology and Classification

• Ureaplasma belongs to the class Mollicutes and family Mycoplasmataceae
• Two species affect humans:
  • Ureaplasma urealyticum (biovar 2)
  • Ureaplasma parvum (biovar 1)
• Contains 14 known serotypes 1
• Key characteristic: ability to metabolize urea through urease enzyme activity
• Small genome size with limited metabolic capabilities
• Lacks cell wall (intrinsically resistant to beta-lactam antibiotics)

Virulence Factors

• Multiple Banded Antigen (MBA): primary surface antigen that elicits host immune response
• Phospholipases A and C: damage host cell membranes
• IgA protease: helps evade mucosal immunity
• Urease: produces ammonia which can damage tissues 1

Clinical Significance

Urogenital Infections

• Nongonococcal urethritis (NGU): Ureaplasma urealyticum is recognized as a causative agent 2
• Chronic prostatitis and epididymitis: implicated in pathogenesis 1
• Urinary tract infections: may be involved in some cases

Male Infertility

• Associated with decreased semen quality:
  • Reduced semen volume
  • Lower sperm concentration
  • Decreased normal morphology
  • Impaired motility 3, 4
• A meta-analysis revealed that Ureaplasma urealyticum strains were associated with male infertility, while Ureaplasma parvum strains were not 5
• Induces inflammatory responses in the male reproductive tract:
  • Elevated levels of TNF, IL-1β, and IL-6 in semen
  • Increased leukocyte counts including T lymphocytes and neutrophils 4

Pregnancy-Related Complications

• Associated with adverse pregnancy outcomes:
  • Preterm labor
  • Chorioamnionitis
  • Premature rupture of membranes
• Produces cytokines in amniotic fluid that can initiate preterm labor 1

Neonatal Infections

• Can cause diseases in newborns:
  • Chronic lung disease
  • Retinopathy of prematurity 1

Diagnostic Methods

Culture

• Traditional method but challenging due to specialized media requirements
• Takes 2-5 days for results
• Less sensitive than molecular methods

Molecular Methods

• Nucleic Acid Amplification Tests (NAATs) are recommended for detection 6
• Polymerase Chain Reaction (PCR) is the mainstay of diagnosis 1
• Urethral swabs show higher specificity and positive predictive value compared to urine specimens for detection of Ureaplasma urealyticum 6

Treatment Recommendations

First-line Treatment

• Doxycycline 100 mg orally twice daily for 7-10 days is the first-line treatment for Ureaplasma infections 6, 7

Alternative Treatments

• Azithromycin 1.0-1.5 g orally as a single dose is an effective alternative 6
• For pregnant women: erythromycin is preferred 6
• For macrolide-resistant cases: moxifloxacin 400 mg daily for 7-14 days 6

Management of Persistent Infections

• If symptoms persist after doxycycline treatment, switch to azithromycin 500 mg on day 1, then 250 mg for 4 days 6
• If symptoms persist after azithromycin, switch to moxifloxacin 400 mg daily for 7-14 days 6
• Failure to improve within 3 days requires reevaluation of both diagnosis and therapy 6

Important Clinical Considerations

• Asymptomatic colonization is common, particularly with Ureaplasma parvum
• Routine screening for Ureaplasma is not recommended in asymptomatic individuals 6
• Testing is indicated in:
  • Persistent or recurrent urethritis after treatment for other STIs
  • Non-gonococcal urethritis where other causes have been ruled out
  • Male infertility evaluations, especially with abnormal semen parameters 6
• Partner notification and treatment is essential to prevent reinfection 6
• Antimicrobial resistance to macrolides, tetracyclines, and fluoroquinolones has been reported, with biovar 2 (U. urealyticum) maintaining higher sensitivity rates 1

Pitfalls and Caveats

• High colonization rates in healthy individuals make interpretation of positive results challenging
• The pathogenic role depends on bacterial load, host factors, and specific species/serotypes
• Treatment should be targeted at symptomatic individuals or those with specific clinical indications
• Resistance patterns vary geographically and should be considered when selecting therapy
• Follow-up is recommended if symptoms persist or recur after treatment 6