Chlamydia infection

Definition

• Genital chlamydia infection is a sexually transmitted infection with Chlamydia trachomatis, an obligate intracellular, Gram-negative bacterium.

Classification

• Serovars D–K cause urogenital, ocular and rectal infections, L1–L3 lymphogranuloma venereum, and A–C trachoma.

Occurrence & epidemiology

Epidemiology

• Chlamydia trachomatis is one of the most common bacterial causes of sexually transmitted infection worldwide; the WHO estimated about 128.5 million new infections among adults aged 15 to 49 in 2020.
• In 2020, global prevalence in this age group was 4.0 % in women and 2.5 % in men; young people are more often affected.

Aetiopathogenesis

Aetiology and risk factors

• Transmission occurs through vaginal, oral or anal sex and perinatally from mother to newborn.

Clinical features

Clinical Presentation

• The pathogen: C. trachomatis (serovars D–K).
• Preferentially affected is: columnar epithelium (endocervix, urethra).
• Possible symptoms: cervicitis, contact bleeding, dysuria.
• Ascending infection leads to: endometritis, salpingitis, tubo-ovarian abscess.

• More than 75 % of women are asymptomatic; possible symptoms are a change in discharge, intermenstrual or postcoital bleeding, lower abdominal pain and burning on urination.
• Cervicitis with a yellow, mucopurulent exudate and cervical ectopy is characteristic.
• Ascending infection causes pelvic inflammatory disease; long-term consequences are infertility and an increased risk of ectopic pregnancy.
• Further manifestations are perihepatitis (Fitz-Hugh-Curtis syndrome) with right upper quadrant pain and, in the newborn, conjunctivitis and pneumonia.

Diagnosis

• The gold standard is nucleic acid amplification testing (NAAT); urine samples are less sensitive than swabs, for example from the vagina.
• Cell culture is less sensitive and technically demanding, so NAAT is preferred over it.

Keep learning in the app

Further reading (selection)

1. Addressing Challenges in Chlamydia trachomatis Detection: A Comparative Review of Diagnostic Methods (Medicina (Kaunas) 2024, PubMed Central)
2. WHO fact sheet: Chlamydia
3. MSD Manual Professional: Urogenital Chlamydial Infections
4. DocCheck Flexikon, Chlamydia trachomatis

Cross-references