[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Intracellular and atypical bacteria](https://durgical.com/en/microbiology/groups/intracellular-and-atypical-bacteria/) › Mycoplasma genitalium / Ureaplasma

[Microbiology](https://durgical.com/en/microbiology/) · [Intracellular and atypical bacteria](https://durgical.com/en/microbiology/groups/intracellular-and-atypical-bacteria/)

# Mycoplasma genitalium / Ureaplasma

- Bacterium
- Does not Gram-stain
- Exam priority: medium

Genital mycoplasmas: M. genitalium causes persistent urethritis and is increasingly drug-resistant; Ureaplasma is usually a coloniser.

Updated 2026-11-01

## Key points

- M. genitalium: a common cause of urethritis that persists after doxycycline
- Very high macrolide resistance: resistance-guided treatment
- Ureaplasma is often just a coloniser

## At a glance

**Gram**
Does not Gram-stain

**Shape**
Pleomorphic, wall-less

**Oxygen**
Facultative anaerobes

**Family**
Mycoplasmataceae

**Stain**
Do not stain with Gram

## Morphology

- No cell wall, like M. pneumoniae
- Ureaplasma hydrolyses urea (urease)
- M. genitalium barely grows in culture

## Transmission

- Sexual contact
- Ureaplasma: also mother to baby in pregnancy or birth

**Reservoir:** Human urogenital tract

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- M. genitalium adheres to urogenital epithelium and causes inflammation
- Mutations conferring resistance to macrolides and fluoroquinolones
- Ureaplasma: pathogenic only at high load or in special settings (preterm infants, immunosuppression)

## Diseases it causes

- Non-gonococcal urethritis, especially persistent or recurrent
- Cervicitis and possible pelvic inflammatory disease (M. genitalium)

## Clinical picture

- Dysuria and urethral discharge that persists after usual treatment
- Cervicitis with post-coital bleeding
- Ureaplasma has been linked to chorioamnionitis and lung disease in preterm infants

## Diagnosis

- NAAT for M. genitalium on urine or swab in recurrent urethritis or cervicitis
- Macrolide-resistance testing when available
- Screening people without symptoms is not recommended

## Treatment

Two-step, resistance-guided therapy: doxycycline to lower the load, followed by azithromycin if the strain is macrolide-sensitive or moxifloxacin if resistant. Macrolide resistance is very high, and single-dose azithromycin drives it.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

- [Doxycycline](https://durgical.com/en/pharmacology/doxycycline/)
- [Azithromycin](https://durgical.com/en/pharmacology/azithromycin/)
- [Moxifloxacin](https://durgical.com/en/pharmacology/moxifloxacin/)

## Prevention

- Condoms
- Evaluation and treatment of sexual partners

## Memory aid

When urethritis «won't give up» after the first treatment, think of the genital mycoplasma, the stubborn little one that learned to resist.

## Test yourself

Think of the answer, then tap the question to see it.

## Which organism is suspected in persistent non-gonococcal urethritis?

Mycoplasma genitalium, the most frequent cause of persistent or recurrent urethritis.

## Why is single-dose azithromycin avoided for M. genitalium?

Because it selects macrolide-resistant strains and often fails.

## Which characteristic enzyme does Ureaplasma have?

Urease, which hydrolyses urea (hence its name).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/microbiology/mycoplasma-genitalium-ureaplasma/)

## Related

- [Mycoplasma pneumoniae](https://durgical.com/en/microbiology/mycoplasma-pneumoniae/)
- [Chlamydia trachomatis](https://durgical.com/en/microbiology/chlamydia-trachomatis/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

[← Back to the group: Intracellular and atypical bacteria](https://durgical.com/en/microbiology/groups/intracellular-and-atypical-bacteria/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Mycoplasma genitalium - STI Treatment Guidelines](https://www.cdc.gov/std/treatment-guidelines/mycoplasmagenitalium.htm) (Centers for Disease Control and Prevention (CDC), 2021); [Urethritis and Cervicitis - STI Treatment Guidelines](https://www.cdc.gov/std/treatment-guidelines/urethritis-and-cervicitis.htm) (Centers for Disease Control and Prevention (CDC), 2021); [Sexually transmitted infections (STIs)](https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-(stis)) (World Health Organization (WHO), 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/microbiology/mycoplasma-genitalium-ureaplasma/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/mycoplasma-genitalium-ureaplasma/