Chlamydial Infection


Chlamydia is a common sexually transmitted disease caused by bacteria called Chlamydia trachomatis.

Chlamydia trachomatis has a number of
serovars and causes many different human infections.

  • Eye: trachoma; inclusion conjunctivitis
  • Genital tract: lymphogranuloma venereum, non-gonococcal urethritis, cervicitis, salpingitis
  • Respiratory tract: pneumonia

Chlamydia trachomatis immunotypes D- Kare is isolated in about 50% of cases of non-gonococcal urethritis and cervicitis by appropriate techniques.

Clinical features

  • Chlamydial infection are asymptomatic, but when an
    incubation period can be determined, it is usually about 10-20 days
  • Co-infection with gonococci and chlamydiae is common
  • C. trachomatis is an important cause of non gonococcal urethritis in males, and in females
    cervicitis, salpingitis, or pelvic inflammatory disease
  • Urethral or cervical discharge tends to be less painful, less purulent, and watery in chlamydial compared with gonococcal infection
  • On physical examination, the cervix may show contact bleeding in addition to the discharge
  • A patient with urethritis or cervicitis and absence of gram-negative diplococci on Gram
    stain and of N. gonorrhoeae on culture is assumed to have chlamydial infection


  • Epididymo-orchitis and sterility in males.
  • Pelvic inflammatory disease (PID) and infertility in females.
  • Adverse pregnancy outcomes.
  • Conjunctivitis and pneumonia in the newborn

Differential diagnoses

  • Other causes of urethral and vaginal discharge (e.g Gonorrhoea)


  • Microscopy, culture and sensitivity (of discharge)
  • Direct immunofluorescence assay
  • Enzyme-linked immunoassay
  • DNA probe test
  • Ligase chain reaction (LCR)

Treatment objectives

  • Eliminate the organism in the patient and sexual partner(s)
  • Prevent re-infection
  • Prevent complications
  • Counsel and screen for possible co-infection with HIV so that appropriate management can be instituted

Drug therapy

Recommended regimen

  • Doxycycline 100 mg orally, every 12 hours for 7 days


  • Azithromycin 1 g orally, in a single dose

Chlamydial infection during pregnancy

Recommended regimen:

  • Erythromycin 500 mg orally every 6 hours for 7 days


  • Amoxycillin 500 mg orally every 8 hours for 7 days

Neonatal chlamydial conjunctivitis

This typically has an incubation period of 10-14 days compared to 2-3 days for gonococcal opthalmia

Recommended regimen:

  • Erythromycin syrup 50 mg/kg per day orally, every 6 hours for 14 days

Alternative regimen:

  • Trimethoprim 40 mg with sulfamethoxazole 200 mg orally, every 12 hours for 14 days


  • There is no evidence that additional
    therapy with a topical agent provides further benefit
  • If inclusion conjunctivitis recurs after therapy has been completed, erythromycin treatment should be reinstituted for 2 weeks
  • It is important to treat the mother and her sexual partner

Notable adverse drug reactions, caution and contraindications

Doxycycline and tetracycline

  • Caution in patients with hepatic impairment, systemic lupus erythematosus and myasthenia gravis
  • Antacids, aluminium, calcium, iron,
    magnesium and zinc salts, and milk
    decrease the absorption of tetracyclines
  • Deposition of tetracyclines in growing bones and teeth (by binding to calcium) causes staining and occasionally dental hypoplasia
  • It should not be given to children under 12 years, or to pregnant or breast-feeding women
  • With the exception of doxycycline,
    tetracyclines may exacerbate renal failure and should not be given to patients with kidney disease
  • It may cause nausea, vomiting and diarrhoea; hypersensitivity reactions.
  • Headache and visual disturbances may indicate benign intracranial hypertension
  • There can be candidal superinfection with prolonged therapy

Azithromycin and Erythromycin

  • Erythromycin estolate is contraindicated during pregnancy because of drug related hepato-toxicity; only erythromycin base or erythromycin ethylsuccinate should be used
  • Erythromycin should not be taken on an empty stomach.
  • Caution in persons with arrhythmias
  • Infants should be followed up for
    symptoms and signs of infantile
    hypertrophic pyloric stenosis (has been reported in infants less than 6 weeks exposed to this drug)


  • Caution where there is a history of allergy
  • Erythematous rashes common in
    glandular fever, cytomegalovirus
    infection, acute or chroni lymphocytic leukaemia with pityriasis rosea, and allopurinol use


  • Counselling, Compliance, Condom use and Contact treatment.

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