Causes of Chlamydia Infection
The bacterium Chlamydia trachomatis causes Chlamydia, an infection transmitted by sexual contact. Among Americans, it is the most commonly reported bacterial infection. It is also one of the most frequently sexually transmitted diseases worldwide. The infection causes an ocular infection called “trachoma,” which is the leading infectious cause of blindness worldwide. (6)
Among females, the cervix is the most commonly infected anatomic site. It can manifest as procitis (inflammation of the lining of the rectum), cervicitis (inflammation of the cervix), urethritis (inflammation of the both male and female urethra), pelvic inflammatory disease, and perihepatitis (inflammation of the coating of the liver). Untreated chlamydial infections in women increase the risk of infertility and ectopic pregnancy, which can lead to high medical costs. Pregnant women are also at risk if they have an infection during pregnancy. Conjunctivitis and/or pneumonia may also occur in infants born vaginally to mothers with genital Chlamydia trachomatis.
Chlamydia trachomatis infection can cause urethritis (inflammation of the urethra), epididymitis (inflammation of the epididymis), reactive arthritis (inflammation of the joints), prostatitis (inflammation of the prostate), or proctitis (inflammation of the liver) in men. Men and women who are infected with C trachomatis may also experience lymphogranuloma venereum, conjunctivitis, and haryngitis. Chlamydia trachomatis causes lymphogranuloma venereum (LGV), a less common disease characterized by severe proctocolitis (inflammation of the colonic mucosa) and enlarged lymph nodes.
A chlamydia infection in the genital area is the most commonly reported bacterial infection in the U.S. and the most common sexually transmitted infection worldwide. U.S. women experience urogenital infections at twice the rate of U.S. men. Men between 20-24 years of age have a higher incidence than women 15-24 years of age.
With two developmental forms and an infectious cycle, Chlamydia is unique among bacteria. Among them are the reticulate body (RB) and the infectious forms known as the elementary body (EB). Host cells take up the EB, making it metabolically inactive. The EB will differentiate into the metabolically active RB in the host cell. The RB will then utilize host energy sources and amino acids to replicate and form new EB, which will then infect other cells. In women, C trachomatis targets the squamocolumnar epithelial cells of the endocervix and upper genital tract, and in men, it targets the rectum, conjunctiva, and urethra.
Direct contact with infected tissue, such as vaginal, anal, or oral sex, can transmit the bacterium. A mother infected with the bacteria can pass it on to her newborn during childbirth.
Asymptomatic Chlamydia trachomatis infection is very common, but the consequences of undiagnosed or untreated infection can be severe. Screenings are therefore recommended. A screening for C. trachomatis is recommended for all pregnant women. Sexually active females should be screened annually, particularly those younger than 25. If a woman has risk factors for sexually transmitted infections, she should be screened. New or multiple sexual partners, sexual partners with multiple concurrent partners, previous/coexisting STIs, inconsistent condom use, exchanging sex for money or drugs are risk factors. Additionally, chlamydial infections should be screened in men who have sex with men. Screening should ideally be done at the time of the initial presentation and annually in HIV patients. Individuals entering a correctional facility should be screened for chlamydia if they are women 35 years old or younger and men 30 years old or younger.
- trachomatis is considered a notifiable infection in the United States. State and local laws apply to disease reporting. When an STI is found in an index patient, his or her sexual partners should be notified, examined, and treated. In some cases, partner therapy may be expedited. Providers can prescribe antibiotics to partners without establishing a physician-patient relationship using the expedited partner therapy.
It is important to educate affected people and the general population about the potentially serious consequences of chlamydia infections and the importance of screening. A patient should also be informed that urinalysis is often performed without invasive procedures. Patients who have been educated may be more likely to agree to screening when they might otherwise hesitate.