NAME: Chlamydia trachomatis
SYNONYM OR CROSS REFERENCE: Trachoma, Lymphogranuloma venereum
CHARACTERISTICS: C. trachomatis, of the Chlamydiaceae family, is a nonmotile, gram negative, obligate intracellular pathogen that is around 0.3-1 µm in diameter Footnote 1-Footnote 3. Chlamydial species have a unique and complex biphasic life cycle, where they are infectious during only one life stage Footnote 4. They have an elementary body form which is adapted for extracellular survival and a reticulate body form which is involved in intracellular growth and replication Footnote 1, Footnote 2, Footnote 5. There are 18 serovars of C. trachomatis; 4 serovars cause trachoma, 5 serovars cause lymphogranuloma venereum (LGV) and the remainder cause a variety of other sexually transmitted infections Footnote 1.
PATHOGENICITY/TOXICITY: Ocular trachoma (or simply trachoma): C. trachomatis (serovars A, B, Ba, and C) can cause acute inflammation of the epithelium of the eye. In endemic areas, re-infection often occurs resulting in chronic inflammation and eventually blindness Footnote 2, Footnote 6.
Lymphogranuloma venereum (LGV): Generally caused by serovars L 1, 2, and 3, infection first presents as genital ulcers followed by lymphadenophathy, with iliac lymphatic glandulae commonly present in women Footnote 7. Symptoms include chills, headache, myaglias, and arthralgias. Infection can further spread into the eyes, central nervous system, heart and lungs. Untreated LGV can result in lymphatic obstruction and elephantiasis of genitalia Footnote 8. A cluster of LGV with a new strain, L2b, has been observed in men-who-have-sex-with-men in Europe and North America, presenting mainly as proctitis Footnote 9.
Genital infections: Other serovars cause infection and inflammation of the reproductive tract, urethritis, proctitis, vaseitis, and epididymitis in men, urethritis, endometritis, salpingitis, and cervicitis in women, which can lead to cervical cancer Footnote 7. Infections may be asymptomatic. Symptomatic female patients often experience pelvic pain, burning urination, and abnormal vaginal bleeding, with inflammation of the endocervical columnar epithelium Footnote 10. Symptomatic male patients often experience faint, watery discharge from the penis, urethral itch and burning on urination. Men who have sex with men may experience symptoms due to proctitis Footnote 10. Untreated infection can result in long-term sequelae including pelvic inflammatory disease and infertility in women, epididymitis and possible infertility in men and reactive arthritis (Reiter’s syndrome) and uveitis in both men and women. The infection can also be passed to newborns during childbirth resulting in conjunctivitis or pneumonia Footnote 1, Footnote 2. Infection may result in pregnancy complications, such as abortion, stillbirth, prematurity, and intrauterine fetal infections Footnote 7. Neonatal infections include conjunctivitis and pneumonia.
EPIDEMIOLOGY: C. trachomatis infections occur worldwide. Ocular trachoma is endemic in over 50 countries, primarily developing countries in Africa, Middle East, Indian sub-Continent and Southeast Asia. It is the leading cause of infectious blindness Footnote 6. LGV is also endemic in developing countries in Africa, South America, Asia and the Caribbean. The greatest risk factors for infection are age and sex, where rates of infection are observed to be highest in females at 15-24 years of age, and males at 20-24 years Footnote 10. However, there have been an increasing number of cases in the developed world among men who have sex with men Footnote 8. C. trachomatis is the leading cause of bacterial genital infections in developed countries Footnote 2, Footnote 10.
HOST RANGE: Humans.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Trachoma generally results from transmission by close contact with infected individuals, fomites, and flies Footnote 6. LGV can be transmitted through vaginal, anal or oral sexual contact Footnote 9. Genital infections are transmitted sexually through direct genital-genital or genital-anal contact Footnote 10. Vertical transmission to newborns can also occur, most commonly during passage through the birth canal Footnote 1, Footnote 2, Footnote 7, Footnote 10.
INCUBATION PERIOD: 7-14 days for trachoma and genital infections, 3-30 days for LGV Footnote 2.
COMMUNICABILITY: Transmission between humans is highly common, and infection can be spread by both symptomatic patients and asymptomatic carriers Footnote 10.
RESERVOIR: Humans Footnote 2.
DRUG SUSCEPTIBILITY: Susceptible to tetracyclines, macrolides, rifampicin and recent fluoroquinolones Footnote 2.
DRUG RESISTANCE: Drug resistance in clinical settings has not been clearly documented, but multiple drug-resistant strains may be emerging against azithromycin, doxycycline, and ofloxacin Footnote 12.
SUSCEPTIBILITY TO DISINFECTANTS: No information available on this specific pathogen, however, similar organisms have been observed to be susceptible to 1% sodium hypochlorite, 70 % ethanol, 0.5% glutaraldehyde, iodines, and formaldehyde Footnote 13-Footnote 16.
PHYSICAL INACTIVATION: No information available on this specific pathogen, however, similar organisms have been observed to be susceptible to moist heat (121°C for at least 15 min); dry heat (160-170°C for at least 1 hour); low temperature sterilization (i.e. Ethylene oxide Footnote 17, Footnote 18or plasma sterilization Footnote 19, Footnote 20).
SURVIVAL OUTSIDE HOST: It can survive on surfaces for 2-3 hours under humid conditions Footnote 21.
SURVEILLANCE: Monitor for symptoms. Diagnosis is based on the culture isolation of C. trachomatis or detection by nucleic acid amplification tests, from swabs, biopsies or urine specimens. Serological tests, such as ELISA and PCR methods can also be used to confirm infection Footnote 2, Footnote 10, Footnote 22.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Administer proper drug therapy for trachoma (azithromycin or topical tetracycline) Footnote 6, lymphogranuloma venereum (doxycycline) Footnote 8, and gential infections (azithromycin) Footnote 8.
PROPHYLAXIS: None. Annual check-ups (pelvic and genital examination) of sexually active women under 25 years of age can reduce clinical manifestations of infection Footnote 10.
LABORATORY-ACQUIRED INFECTIONS: Laboratory-acquired cases of Lymphogranuloma venereum and trachoma have been reported Footnote 23. There have also been cases of respiratory illness associated with exposure to C. trachomatis aerosols in the laboratory Footnote 24.
SOURCES/SPECIMENS: Genital, bubo and conjunctival fluids Footnote 25.
PRIMARY HAZARDS: Accidental parenteral inoculation and exposure of mucous membranes of the eyes, nose and mouth to infected material. Aerosols also pose a risk for infection Footnote 25.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 26.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infected or potentially infected materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 27.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 27.
SPILLS: Allow aerosols to settle, and while wearing protective clothing, gently cover the spill with paper towels and apply appropriate disinfectant starting at the perimeter, working inwards towards the centre. Allow sufficient contact time before clean up (30 minutes), and then repeat Footnote 27.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing Footnote 27.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled Footnote 27.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: December 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2011