Chlamydia trachomatis



  • Chlamydia trachomatiscan cause a variety of infections, including sexually transmitted disease (STDs) and eye infections.
  • Up to 80% of people infected with Chlamydia are unaware that they have it.
  • Chlamydia can lead to severe complications if left untreated.
  • Gonorrhoea and Chlamydia are often found together.


Chlamydia trachomatis is a common cause of bacterial sexually transmitted disease, causing either a cervicitis or urethritis (inflammation of the cervix or urethra, respectively), as well as a condition called lymphogranuloma venereum (LGV). LGV is characterised by genital ulcers and enlarged lymph nodes in the groin region. C. trachomatis is also a common cause of blindness in developing areas of the world, such as North Africa and India.

The organism can be found in the mucous membrane of reproductive organs, such as the cervix (the end of the uterus that protrudes into the vagina) and urethra (the tube that drains urine from the bladder). It can also exist in the throat or rectum. It can be spread from person to person, either directly (e.g. by sexual contact or hands), or by dust particles and flies (one of the routes by which eye infection is spread).

It can be easily cured if treated with antibiotics. Unfortunately, Chlamydia is often not detected, as it is common for individuals with this sexually transmitted infection to have no symptoms at all. In fact, up to 80% of women with Chlamydia are unaware that they have the disease until they develop serious complications. Children with recurrent eye infections often develop scarring of the conjunctiva and cornea. They are often only treated late in the disease - this is often a result of a combination of poor education and poor access to health care. Ocular trachoma is one of the most common causes of preventable blindness.

It is common for women with untreated Chlamydia to develop pelvic inflammatory disease, an infection that spreads from the vagina and cervix to the uterus and fallopian tubes. Other complications include ectopic pregnancies and infertility. Men with Chlamydia may develop epididymitis, an inflammation of the testicular tubes. Chlamydia is also associated with an increased incidence of pre-term birth. Babies born to mothers with Chlamydia can be infected during passage through the infected birth canal. This can lead to pneumonia or eye problems such as neonatal conjunctivitis.

As Chlamydia is hard to detect, especially in women, it is important to be tested regularly during routine annual visits and to practice safe sex to prevent transmission.


Chlamydia trachomatis is a bacterium which lives inside other cells (unlike most other bacteria). At one time, Chlamydial organisms were thought to be large viruses, but they are now known to be more closely related to bacteria. This sexually transmitted disease is usually transmitted through vaginal or anal sex, or other intimate contact with the genitals, mouth or rectal area. Even if a person has no symptoms, they can still infect others with the disease.

The organism can also infect the eye as a result of accidental inoculation of the eye with infective material from the genital tract, as well as inoculation through small dust particles or transmitted by flies, which have been contaminated with the organism from another infected person. Additionally, a pregnant woman may transmit the infection to her newborn during delivery.



In women

Women with an early infection of Chlamydia usually do not have any symptoms. In some cases, the following symptoms can be present:

  • Vaginal discharge
  • Mild discomfort when urinating
  • Cloudy urine
  • Irregular menstrual bleeding
  • Lower abdominal pain
  • Fever
  • General tiredness

In men

  • Frequent urge to urinate or a burning sensation when urinating
  • Cloudy urine
  • A discharge from the penis

Lymphogranuloma venereum (LGV)

  • Genital ulcers, usually occurring one to two weeks after infection. These ulcers are usually fairly small and painless, and are generally not noticed.
  • The ulcers often heal without treatment.
  • One to two weeks later, enlarged groin lymph nodes appear, often associated with sore joints, headache and fever.
  • The nodes can ulcerate or rupture draining thick yellow pus. The infection may heal with scarring in the groin region.

Eye infections


  • Sometimes, infections of the eyes cause a relatively mild conjunctivitis. This is the form seen in newborns infected via the birth canal, and can also sometimes be seen in adults. It seldom causes permanent damage to the eye, even if untreated. However, subclinical infection may persist, leading to scars and corneal lesions.


  • Trachoma is thought to result from repeated infection with the organism, and may also be a result of an abnormal host immune response to the bacterium.
  • Trachoma starts out as conjunctivitis, characterised by little follicles (white bumps) on the conjunctiva, and with persistent infection or re-infection, the cornea becomes progressively scarred and ulcerated, ultimately resulting in blindness.


The incubation period (the time between exposure to the bacteria and the beginning of symptoms) can be days or months. In many cases, especially in women who acquire the organism as a sexually transmitted infection, symptoms may never appear. If there are symptoms, they are usually apparent one to three weeks after exposure.

If Chlamydia is detected early, it can be cured easily and there should be no long-term consequences. However, as many people do not know that they have the disease, it may take up to two years for the body to destroy the bacteria. Untreated, Chlamydial urethritis or cervicitis may lead to complications.

Men may develop the following clinical manifestations:

  • Epididymitis (inflammation of the testicular tubes)
  • Infection of the prostate (prostatitis)
  • Infection of the urethra (urethritis)
  • Infection of the lining of the eye (conjunctivitis)
  • Infection of the rectum (proctitis)
  • Reiter's syndrome (an auto-immune arthritis-like condition)

. Clinical manifestations in women can include:

  • Urethritis
  • Pelvic inflammatory disease: Infection of the fallopian tubes (salpingitis) and infection of the lining of the uterus (endometritis)
  •  Infection of the cervix (cervicitis)
  • Abnormal cells on the cervix (cervical dysplasia)
  • Infection of Bartholin's glands (Bartholinitis)
  • Conjunctivitis
  • Pharyngitis
  • Proctitis

Women are more likely to develop long-term complications. These include:

  • Infertility
  • Ectopic pregnancies (tubal pregnancies)
  • Perihepatitis (inflammation of the area around the liver)
  • Pelvic abscesses

Pregnant women are at greater risk of the following:

  • Miscarriage
  • Pre-term labour
  • Premature rupture of the membranes
  •  Infection of the uterine lining (post-partum endometritis)

Approximately 50 to 70% of all newborns of women with untreated Chlamydia are at risk of being infected during passage through an infected birth canal. This can lead to:

  • Conjunctivitis
  • Pneumonia
  • Pharyngitis (inflammation of the throat), rhinitis
  • Infection of the vagina or rectum

Risk factors

The risk of being infected with Chlamydia from a single act of unprotected sex with an infected partner is estimated to be about 40% for women and 20% for men.

The following people are most at risk:

  • People who have unprotected sex
  • People who have multiple sexual partners
  • Sexually active adolescent women
  • People who have a history of STDs
  • Women who use intrauterine devices (IUDs) or take oral contraceptives
  • People who have gonorrhoea
  • Babies born to women with Chlamydia

When to see a doctor

  • Because many people are unaware that they have Chlamydia, people who are sexually active should ask to be tested during all routine visits.
  • If there are any symptoms of Chlamydia, immediate medical attention is needed.
  • If there are any symptoms of complications, such as high fever (37,7°C or higher), flu-like symptoms such as chills, backache, weight loss and diarrhoea, bleeding after intercourse, severe nausea, severe pelvic pain or recurring back pain.
  • Although conjunctivitis is usually viral, and usually mild, if you have conjunctivitis which does not appear to be resolving, or there is an associated yellowish discharge from the eye, it would be advisable to visit your doctor.

Visit preparation

  • Be prepared to answer any questions about recent sexual activity.
  • Make a note of any symptoms if present.
  • If you are allergic to penicillin, you should inform the doctor.
  • Abstain from sexual intercourse while waiting for a medical examination.
  • All sexual partners should be notified, as they will also need to be tested.


The doctor may perform a pelvic and genital examination, followed by an analysis of cervical fluid or penile discharge. The fluids are examined under a microscope with the aid of a substance that makes the bacteria glow. As many infections of the genitals or urinary system have similar symptoms, several tests for STDs and non-STD infections may be done. Diagnosis of the eye infection is done in a similar fashion - a smear is made of the discharge from your eye, and is examined under a microscope.

The organism Chlamydia trachomatis is very difficult to grow in the laboratory, so specimens are not routinely sent for culture of the organism. However, newer tests designed to detect the DNA of the organism have been developed, and are in use in certain laboratories in South Africa. They are very sensitive tests (they detect most if not all cases of Chlamydia), although they do sometimes miss cases. The test can be done on a variety of specimens, such as urine, vaginal swabs, urethral swabs, or cervical swabs. The reliability of the test has been shown in some studies to vary depending on what sort of specimen is tested. The other disadvantage is the cost of the test.



Chlamydia is easily cured if detected early and, in uncomplicated cases, the cure rate is 95%. It is usually treated with antibiotics such as tetracycline, doxycycline, azithromycin or erythromycin. Pregnant women should not be treated with tetracycline, but rather with erythromycin. Babies born to women with Chlamydia will be treated with eye drops at birth and oral antibiotics. These antibiotics should prevent further complications.

If complications such as pelvic inflammatory disease are present, a combination of antibiotics will be needed. The other drugs do not treat the Chlamydia, but are used in case other bacteria such as gonococci are also involved in the sexually transmitted infection.

There is fortunately little resistance of the bacterium to antibiotics. However, it is extremely important to complete the course of antibiotics, even if the symptoms have cleared up.

All recent sexual partners have to be treated as well. People who have been exposed to Chlamydia should be treated even if they have no symptoms.


Sexual contact should be avoided until follow-up tests show no signs of infection.

Re-infection is common. It is therefore important to notify your sexual partner or partners of the infection. They would also have to be tested and treated if necessary.

Careful hand washing is essential to avoid transmission of the bacteria to the eyes.


  • Always use condoms during sex and foreplay to reduce the risk of infection. The female condom  can also reduce the risk of being infected.
  • As drugs or alcohol can interfere with a person's ability to make responsible decisions regarding protected sex, it is best to avoid sexual intimacy when intoxicated.
  • As Chlamydia is often asymptomatic in women, it is extremely important to be tested during routine visits to the doctor.
  • Pregnant women, or those who plan to have children, should be tested for Chlamydia.

Previously reviewed by Dr Andrew Whitelaw, MBBCh (Witwatersrand), MSc (UCT), FCPath (Micro) (SA) Senior registrar, Department of Microbiology, University of Cape Town and Groote Schuur Hospital

Reviewed by Dr Miscka Moodley, Microbiologist, UCT, August  2011

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