Aetiology
Genital chlamydial infection is caused by the obligate intracellular bacterium C. trachomatis.
Chlamydia is the most commonly reported curable bacterial STI in the UK. The highest prevalence rates are in 15–24-year olds. Chlamydia infection has a high frequency of transmission, with concordance rates of up to 75% of partners being reported.
Natural History
The natural history of chlamydia infection is poorly understood. Infection is primarily through penetrative sexual intercourse, although the organism can be detected in the conjunctiva and nasopharynx without concomitant genital infection.
If untreated, infection may persist or resolve spontaneously.
Studies have shown that clearance increases with the duration of untreated infection, with up to 50% of infections spontaneously resolving approximately 12 months from initial diagnosis – the mechanism of clearance is unclear.
Chlamydia infection can cause significant short- and long-term morbidity. Complications of infection include pelvic inflammatory disease (PID), tubal infertility and ectopic pregnancy.
Clinical Features
Women symptoms
- In the majority, infection is asymptomatic
- Increased vaginal discharge
- Post-coital and intermenstrual bleeding
- Dysuria
- Lower abdominal pain
- Deep dyspareunia
Women signs
- Mucopurulent cervicitis with or without contact bleeding
- Pelvic tenderness
- Cervical motion tenderness
Men symptoms (may be so mild as to be unnoticed):
- Urethral discharge
- Dysuria
Extra-genital infections
Rectal infection
Rectal infection is usually asymptomatic, but anal discharge and anorectal discomfort may occur.
Pharyngeal infections
Usually asymptomatic.
Conjunctival infections
Usually sexually acquired - the usual presentation is of unilateral low-grade irritation; however, the condition may be bilateral.
Complications
Women
- PID, endometritis, salpingitis
- Tubal infertility
- Ectopic pregnancy
- Sexually acquired reactive arthritis (SARA) (<1%)
- Perihepatitis
Men
- Sexually aquired reactive arthritis
- Epididymo-orchitis
LGV (see also BASSH LGV guideline)
Symptoms
- Asymptomatic infection may occur
- Tenesmus
- Anorectal discharge (often bloody) and discomfort
- Diarrhoea or altered bowel habit
Diagnosis
The current standard of care for all cases, including medico-legal cases and extra-genital infections, is NAAT.
Although no test is 100% sensitive or specific, NAATs are known to be more sensitive and specific than EIAs.
Vulvo-vaginal swabs (VVS): A vulvo-vaginal sample is the specimen of choice in women (Level IIa, Grade B).
Endocervical swabs: These have been shown to be less sensitive than VVS and require a speculum examination performed by an HCW. Inadequate specimens reduce the sensitivity of NAATs.
First-catch urine: Variable sensitivities have been reported using first-catch urine (FCU) specimens in women. FCU in men is reported to be as sensitive or more sensitive than urethral sampling (Level IIa, Grade B).
Urethral swabs: Can be taken but may be less acceptable than urine samples for patients.
Extra-genital sampling:
Rectal swabs and pharyngeal swabs: NAATs are the assays of choice for both genital and extra-genital samples, though the sensitivities are variable (Level IIa, Grade B).
Management
Recommended regimens *see update, below (September 2018)
Uncomplicated urogenital infection (Level Ia, Grade A) and pharyngeal infection (Level IV, Grade C):
- Doxycycline 100mg bd for seven days (contraindicated in pregnancy)
- Azithromycin 1g orally as a single dose, followed by 500mg once daily for two days
If either of the above treatment is contraindicated:
- Erythromycin 500mg bd for 10–14 days (Level IV, Grade C)
or
- Ofloxacin 200mg bd or 400mg od for seven days (Level Ib, Grade A)
Pregnancy and breast feeding *see update, below (August 2017)
Doxycycline and ofloxacin are contraindicated in pregnancy
Recommended regimens (Level Ia, Grade A)
- Azithromycin 1g orally as a single dose, followed by 500mg once daily for two days
or
- Erythromycin 500mg four times daily for seven days
or
- Erythromycin 500mg twice daily for 14 days
or
- Amoxicillin 500mg three times a day for seven days
Test of cure (TOC)
TOC is not routinely recommended for uncomplicated genital chlamydia infection, because residual, non-viable chlamydial DNA may be detected by NAAT for 3–5 weeks following treatment.
TOC is recommended in pregnancy, where poor compliance is suspected and where symptoms persist.
Contact tracing and treatment
Management of sexual partners:
Services should have appropriately trained staff in PN skills to improve outcomes (Level Ib, Grade A).
All patients identified with C. trachomatis should have PN discussed at the time of diagnosis by a trained healthcare professional.
The method of PN for each partner/contact identified should be documented, as should PN outcomes.
All sexual partners should be offered, and encouraged to take up, full STI screening, including HIV testing and if indicated, hepatitis B screening and vaccination (Level IV, Grade C).
*UPDATE* 26th September 2018
The majority of sexually transmitted infection (STI) guidelines have until recently recommended a 1g single dose of azithromycin (SDA) or 7 days of doxycycline as standard treatment for uncomplicated urogenital and oral chlamydia infection. Mycoplasma genitalium (MGen) is emerging as a significant sexually transmitted pathogen and coinfection rates of 3%-15% with chlamydia have been reported. Recent data demonstrate an increasing prevalence of macrolide resistance in MGen, likely due to the widespread use of SDA to treat STIs, and the limited availability of diagnostic tests for MGen.
In addition, SDA has also been shown to be less effective than doxycycline for rectal CT in MSM , and a meta-analysis of rectal specimens in women showed significant rates of concomitant rectal infections in women with urogenital infection, with no association between reported anal intercourse and rectal infection. This has important implications for treatment, as undertreated rectal chlamydia infection may potentially contribute to re-infection rates.
As a consequence of its potential to select for macrolide resistance in MGen and its inadequacy as a treatment for rectal CT, the British Association for Sexual Health and HIV (BASHH) no longer recommends SDA for treatment of uncomplicated chlamydia infection at any site, regardless of the gender of the infected individual.
Doxycycline 100mg bd for 7 days is now recommended as first line treatment for uncomplicated urogenital, pharyngeal and rectal chlamydia infections, with test of cure (TOC) for diagnosed rectal infections.
To read the full statement, and access the references, please click here.
*UPDATE* 8th August 2017
The CEG has prepared a response to a paper by Muanda et al* which reports an association between spontaneous abortion and use of some antibiotics (including azithromycin) in pregnancy. The CEG sees no reason at the present time to change the recommendations in its current guidelines for treating genital infections in pregnancy based on this recent publication. You can read the statement here. It is also appended to the Chlamydia trachomatis treatment guidelines.
*Muanda FT, Sheehy O, Berard A. Use of antibiotics during pregnancy and risk of spontaneous abortion. CMAJ. 2017; 1(189):625-633.
Download the Full Guidelines
*UPDATE TO FIRST LINE TREATMENT RECOMMENDATION*
26th September 2018
The majority of sexually transmitted infection (STI) guidelines have until recently recommended a 1g single dose of azithromycin (SDA) or 7 days of doxycycline as standard treatment for uncomplicated urogenital and oral chlamydia infection. Mycoplasma genitalium (MGen) is emerging as a significant sexually transmitted pathogen and coinfection rates of 3%-15% with chlamydia have been reported. Recent data demonstrate an increasing prevalence of macrolide resistance in MGen, likely due to the widespread use of SDA to treat STIs, and the limited availability of diagnostic tests for MGen.
In addition, SDA has also been shown to be less effective than doxycycline for rectal CT in MSM , and a meta-analysis of rectal specimens in women showed significant rates of concomitant rectal infections in women with urogenital infection, with no association between reported anal intercourse and rectal infection. This has important implications for treatment, as undertreated rectal chlamydia infection may potentially contribute to re-infection rates.
As a consequence of its potential to select for macrolide resistance in MGen and its inadequacy as a treatment for rectal CT, the British Association for Sexual Health and HIV (BASHH) no longer recommends SDA for treatment of uncomplicated chlamydia infection at any site, regardless of the gender of the infected individual.
Doxycycline 100mg bd for 7 days is now recommended as first line treatment for uncomplicated urogenital, pharyngeal and rectal chlamydia infections, with test of cure (TOC) for diagnosed rectal infections.
To read the full statement, and access the references underpinning this change in recommendation, please click here.
Please navigate to the management section for updated guidance on treatment.
To download a copy of the 2015 Guidelines (with superceded treatment recommendations), click here.