Chlamydia

Cause

Chlamydia is a sexually transmitted infection (STI) caused by Chlamydia trachomatis
Serovars D-K cause urogenital infection, while serovars L1-L3 cause lymphogranuloma venereum (LGV)

Infects endocervix, urethra, rectum and occasionally pharynx and conjunctivae
Transmission is through
- Contact with infected genital secretions
- Sexual practices such as fingering which allow inoculation of infected secretions onto mucous membranes
- Mother to baby at vaginal delivery
Chlamydia is most commonly diagnosed in
- Adolescents and young sexually active adults aged under 30 years
- Sexual contacts of people with chlamydia
- People who have multiple sexual contacts or a new sexual contact
- People who have not consistently used condoms
- Māori and Pacific Peoples

Site of infection	Signs and symptoms
Urethra	Approximately 50% are asymptomatic Dysuria Discharge (penile urethra)
Cervix	Approximately 75% are asymptomatic Vaginal discharge Post coital bleeding Intermenstrual bleeding
Anorectum	Often asymptomatic Discharge
Pharynx	Usually asymptomatic
Complications
Epididymitis or epididymo-orchitis Pelvic inflammatory disease (PID), subfertility, chronic pelvic pain, ectopic pregnancy Reactive arthritis

Patients with possible signs or symptoms of a chlamydia infection
Sexual contacts of people with chlamydia or other STIs
Pregnancy
Before termination of pregnancy
Before intrauterine device (IUD) insertion in people at risk of STIs
Suspected epididymo-orchitis
Suspected PID
Sexually active patients aged under 30 years opportunistically when accessing health care
Men who have sex with men (MSM)
History of sexual assault or intimate partner violence
If the patient requests a sexual health check

Note: If patient is asymptomatic and is concerned about a specific recent sexual event the recommended testing interval is 2 weeks from time of last unprotected sexual intercourse

If the patient is unlikely to return and has not been previously tested, then test opportunistically at the time of presentation and offer a re-test after the appropriate window period

Chlamydia is a common infection, however false positive results may occur in low prevalence populations – discuss with microbiologist or sexual health physician if unexpected positive result

Treatment options

Infection

Recommendation

Alternative

Uncomplicated genital or pharyngeal infection

Doxycycline 100 mg orally twice daily for 7 days

Azithromycin 1 g orally, as a single dose

Only if doxycycline is contraindicated, or patient is highly likely to be non-adherent

Anorectal infection

Doxycycline 100 mg orally twice daily for 7 days if asymptomatic

Seek specialist advice if symptomatic, or refer to anorectal syndromes guideline

Azithromycin 1 g orally, and repeat in 1 week

Only if doxycycline is contraindicated, or patient is highly likely to be non-adherent

Special situations

Situation	Recommendations
Breastfeeding	Azithromycin 1 g orally, as a single dose
Pregnancy	Azithromycin 1 g orally, as a single dose Test of cure recommended 4 weeks after treatment completed Rescreen in 3^rd trimester
Allergy or contraindications	If both treatment options unsuitable, seek specialist advice
Co-infection with gonorrhoea	Ceftriaxone 1g in 3.5 mL 1% lignocaine, intramuscular injection, as a single dose PLUS Doxycycline 100 mg orally twice daily for 7 days Seek specialist advice if rectal co-infection and symptomatic, or refer to anorectal syndromes guideline

Advise to abstain from sex or use condoms for 1 week from the start of treatment and until 1 week after sexual contact/s have been treated
If a patient has an IUD, leave it in place and treat as recommended. Seek specialist advice as needed
Seek specialist advice if symptomatic anorectal infection, as further testing and extended treatment may be required
Consider HIV pre-exposure prophylaxis (PrEP) if rectal chlamydia is diagnosed in a male or transgender person who has anal sex with men

30-50% risk of transmission per act of unprotected intercourse
Contact tracing is important to prevent re-infection and reduce transmission
All sexual contacts in the last 3 months should be notified
Most patients choose to tell contacts themselves; giving written information can be helpful
Notifying all contacts may not be possible e.g. if there is insufficient information or a threat of violence

Management of sexual contacts

Where the last sexual contact with the index case was within the past 2 weeks, or the contact is symptomatic, or unlikely to return for treatment, perform a full sexual health check, and treat for chlamydia without waiting for test results
Where the last sexual contact with the index case was more than 2 weeks previously, and the contact is asymptomatic and likely to return for treatment, it would be reasonable to wait for test results, and treat only if positive
Advise contacts to abstain from sex or use condoms until results are available, and for 1 week from the start of treatment
If contacts test positive for an STI refer to specific guideline
Patient-delivered partner therapy is not legal in Aotearoa New Zealand

Review in 1 week (in person or by phone):

Discuss test results
Check symptoms (if any) have resolved
Ask if any condomless sex in the week post-treatment
Check medication was completed and tolerated
Ensure notifiable contacts have been informed
Check if any risk of re-infection. Retreatment is necessary if re-exposed to an untreated contact

Test of cure

Not routinely recommended, unless in the following situations:

Pregnancy
Rectal chlamydia

Test of cure by nucleic acid amplification test (NAAT) in these situations should be performed at least 4 weeks after treatment is completed. An earlier test of cure could yield a false-positive result due to the presence of chlamydia DNA remnants

Retesting

Re-infection is common
Retesting at 3 months is recommended, to detect re-infection

Consider testing for other STIs, if not undertaken at first presentation, or retesting after the window period