Chlamydia (synonyms: Chlamydia; Chlamydia trachomatis; Chlamydial infection; Chlamydiosis; ICD-10-GM A56.-: Other sexually transmitted chlamydial diseases) are the most common bacterial agents of urogenital infections (infectious diseases affecting the urinary tract and/or reproductive organs) in industrialized countries. Chlamydia is common throughout the world. Chlamydia is a genus of bacteria (gram-negative), of which the subtype Chlamydia trachomatis can cause various diseases. Three species of the genus Chlamydia are known:
- Chlamydia trachomatis [discussed comprehensively below].
- Serotypes A-c as the causative agent of trachoma (synonyms: conjunctivitis (granulosa) trachomatosa, Egyptian granular disease; trachomatous inclusion conjunctivitis) – bacterial inflammation of the eye that can end in blindness.
- Serotypes D-K as pathogens of urethritis (urethritis) and genital infections.
- Serotypes L1-L3 as the causative agent of lymphogranuloma inguinale* (synonyms: venereal granuloma; lymphopathia venerea; lymphogranuloma inguinale (venereum); lymphogranuloma venereum; Nicolas Durand Favre disease) – sexually transmitted disease (STD (sexually transmitted diseases) or STI (sexually transmitted infections) more common in the tropics.)
- Chlamydia psittaci as the causative agent of ornithosis – infection, which manifests itself primarily as atypical pneumonia [see under ornithosis].
- Chlamydia pneumoniae as a causative agent of pneumonia (pneumonia) [see under pneumonia (pneumonia)]
* The disease belongs to the sexually transmitted diseases (STD (sexually transmitted diseases) or STI (sexually transmitted infections)). Humans currently represent the only relevant pathogen reservoir for Chlamydia trachomatis. Occurrence: Chlamydia trachomatis of serotypes D-K as the causative agent of urethritis and genital infections is widespread in Central Europe.Tracheoma and lymphogranulosa inguinale hardly occur in Western industrialized countries. Their occurrence is mainly restricted to tropical countries. Transmission of the pathogen (route of infection) Chlamydia trachomatis of serotypes D-K occurs predominantly through sexual contact, either orally or as smear infection, but can also occur perinatally (during birth). Serotypes A-C are transmitted by infectious eye secretions or by hands or cloths contaminated with them. Transmission of the pathogen (route of infection) Chlamydia psittaci is aerogenic (via inhalation of feces and secretions of infected birds (parrots, pigeons) or other animals). Transmission of the pathogen (route of infection) Chlamydia pneumoniae occurs by inhalation or infectious saliva. The entry of the pathogen into the body occurs parenterally – depending on the pathogen – (the pathogen does not penetrate through the intestine, but enters the blood through the skin (percutaneous infection), through the mucous membranes (permucous infection), through the respiratory tract (inhalation infection), through the urinary tract (urogenital infection), through the genital organs (genital infection) or during birth (perinatal infection) into the body of the newborn). The incubation period (time from infection to onset of disease) is usually between one and three weeks, but can be as long as six weeks. Peak incidence: Young girls in particular are at much higher risk of infection than adult women. Chlamydia trachomatis is the most common sexually transmitted infection (STI) worldwide. According to individual studies, the prevalence of the disease is 10% in 17-year-old girls and 20% in 20 to 24-year-old young women. In Germany, it is estimated that 300,000 genital infections are caused by chlamydia every year. This makes Chlamydia trachomatis the number one sexually transmitted infection (STI). The disease is now also widespread among men who have sex with men (MSM). In a sentinel of the Robert Koch Institute (RKI), the proportion of positive findings in men was 10%. The duration of infectiousness (contagiousness) cannot be specified, as the disease is asymptomatic (symptomless) in the majority of cases and consequently remains undetected at first. The disease leads only to a temporary immunity.Course and prognosis: If detected in time, a chlamydial infection can be treated well with antibiotic therapy and remains without consequential damage. A sexually transmitted disease caused by Chlamydia trachomatis is asymptomatic in the majority of cases in women (up to 80%) and men. However, the disease can lead to sterility (infertility) and increase the risk of tubar gravidity (ectopic pregnancy). In pregnant women, the infection can cause premature birth. Vaccination: A vaccination against Chlamydia is not yet available. In Germany, the disease is not notifiable according to the Infection Protection Act (IfSG). Chlamydia trachomatis diseases of serotypes D-K are presented below.
