Chlamydia trachomatis

Fastidious bacteria that is not encountered commensally as normal flora but only as a pathogen.

Most common bacterial sexually transmitted disease in industrialized countries and probably worldwide.

Rates for women who are approximately twice that of men, in part due to screening recommendations focus on women.

Most common reported notifiable disease.

Rates are highest for  women age 20-24 years and are  5.6 times higher in people who are  Black compared with people who were White.

Prokaryotes that morphologically and structurally resemble gram negative bacteria.

Obligate intracellular organism.

The elementary body is the extracellular stage attached to a susceptible epithelial cell.

Adhesions facilitate entry into epithelial cells by endocytosis and the elementary body develops into membrane bound vesicles which become a replicative form, the reticulate body.

Energy requirement met by obtaining ATP from the host cell and allows for intracellular growth.

Elementary bodies, which are infectious, are released from the cells when the reticulate body divides and condenses into new elementary bodies.

In 2019 1,808,703 cases of chlamydia reported to the CDC corresponding to a rate of 552.8 cases per hundred thousand population.

Reported cases of chlamydial infections among US women versus men were 698.9 versus 399.9 cases per 100,000, respectively.

More cases noted in women, but probably the incidence is the same among the sexes.

Estimated 3-4 million new cases per year in the U.S.

Estimated 90 million cases worldwide.

Significant association with young age, especially in females.

In 2006 for every 100,000 15-19 year old girls almost 3% became infected.

Almost 5% of teenage girls acquire infection each year in the U.S.

In minority populations in the U.S. as many as 30% of teens acquire the infections each year.

Among patients with gonorrhea 10-30% also have chlamydia.

Among patients with infection fewer than 1% are also infected with gonorrhea.

Anatomic site of infection in men is the urethra and the cervix and urethra in women.

Rectal infections common in men who have sex with men.

Proportion of sexually active women screened for infection ranges from 8-40% with a median of 15%.

Among sexually active females aged 14-19, prevalence 6.8% overall.

About 10% of sexually active asymptomatic men are infected.

Majority of genital chlamydia infections in both males and females are asymptomatic.

Burden of infection greatest among sexually active adolescents and young adults, with prevalence among sexually active individuals 14-24 is almost 3 times those aged 25-39.

Prevalece among blacks approximately five times the prevalence in whites.

Recommended to screen all sexually active women aged 25 years or younger.

Screening is with a nucleic acid amplification test and patients at risk include those with new or multiple sex partners, inconsistent condom use and people not in a monogamous relationship, previous or concurrent sexual transmitted infection and exchanging sex for money.

Screening is significantly associated with a lower risk of pelvic inflammatory disease in young women.

The difference in the prevalence of infection between men and women is not significant, but women have more consequence.

Chlamydia may infect the oropharynx, rectum, eye, urogenital tract of both men and women.

Pulmonary infection may occur in infants.

More than 70% of urogenital infections in women, more than 80% of urogenital infections in men, and more than 90% of rectal and pharyngeal infections or asymptomatic.

In women chlamydial infection is usually asymptomatic but can result in transmission.
Untreated chlamydial infections cam progress to symptomatic pelvic inflammatory disease and can result in infertility, chronic pelvic pain, and ectopic pregnancy.
In men genital chlamydia infection is most often asymptomatic but can cause non-gonococcal urethritis, epididymitis, proctotis, and if symptomatic may present with urethritis.
when present, clinical manifestations include urethritis with dysuria and urethral discharge, cervicitis with mucopurulent discharge, pelvic inflammatory disease, epididymitis with fever and testicular pain, or proctitis with rectal pain, discharge, and bleeding.
Chlamydia infection care facilitated HIV infection in both women and men and may potentiate the risk of cervical cancer.

Infection presents greatest health threats to females with ascending infection from the cervix, uterus and the fallopian tubes with pelvic inflammatory disease.

Pelvic inflammatory disease is the main complication of this disease as a result of infection of the lower genital tract with migration to the uterus and fallopian tubes.

Pelvic inflammatory disease associated with lower abdominal pain, often abnormal vaginal bleeding and occasionally fever.

Pelvic inflammatory disease can lead to abscesses in the fallopian tubes or elsewhere in the pelvis.

Symptomatic pelvic inflammatory disease occurs in 10-15% of women with such an infection.

Pelvic inflammatory disease (PID) especially common in patients with repeat infections.

Asymptomatic pelvic inflammatory disease is common and Chlamydia can be detected in the uterus of most infected women.

Responsible for most cases of tubal infertility and ectopic pregnancy unindustrialized countries.

May manifest as cervicitis in females and urethritis in males and females.

Untreated disease can lead to epididymitis in males.

Pregnant women commonly infected, particularly among minority groups.

Cause of 10% of community-acquired pneumonia.

Rare complications include Fitz-Hugh Curtis syndrome, (perihepatitis),  and reactive arthritis.

Infections cause pelvic inflammatory disease , pelvic pain, ectopic pregnancy and tubal infertility.

Infection presents greatest health threats to females with ascending infection from the cervix, uterus and the fallopian tubes with pelvic inflammatory disease.

Results in scarring or blockage of the fallopian tubes, making this infection one of the most common causes of ectopic pregnancy and infertility.

Suggested that 10-15% of untreated infections result in PID (pelvic inflammatory disease).

Can lead to childhood health consequences for babies born to infected mothers.

Can cause infant pneumonia or conjunctivitis.

Now the most common bacteria cause of sexually transmitted disease and such infections are increasing in frequency, while the rate of gonococcal infections is gradually declining.

May be related to cervical cancer.

Most cases ore asymptomatic or cause trivial symptoms increasing the frequency and severity of long-term consequences by delaying the diagnosis and treatment.

Up to half of men who acquire infection of the urethra are without symptoms.

When symptoms appear they usually start 7-21days after exposure.

In men symptoms may appear up to several weeks after acquisition of the infection.

Nongonococcal urethritis is the most common clinical diagnosis in patients with symptoms.

Most common complication in men is acute epididymitis, resulting in painful enlargement of the testicle, usually on one side and associated with fever, and non specific urethritis

Reactive arthritis is an uncommon complication.

Accounts fro 20-40% of cases of nongonococcal urethritis.

Up to 80% of infected women remain asymptomatic and when symptoms occur they are usually mild or nonspecific with variation in vaginal discharge or other minor genital discomfort.

Enhances the susceptibility of infected persons to acquire HIV.

Most such infections of the rectum are asymptomatic, but some will have discharge of pus from the anus, pain and anal itching and rarely bleeding.

Some patients with genital infection also have conjunctivitis.

Without treatment the agent can persist in the genital tract for several months to up to 1 year, especially in females.

Occasionally the infection can persist for years.

As the large majority of infections are cleared spontaneously by the immune system within several months, a new infection usually indicated recent sexual exposure to an infected source.

Lymphogranuloma venereum is caused by serovars  of chlamydia that have emerged the predominantly in populations of men were transgender women who have sex with men with outbreaks of rectal disease.

Main diagnostic process is to identify Chlamydia at the site of infection, by collecting a specimen on swab or by testing the urine.

Better than cultures is utilization of nucleic acid amplification testing where minute amounts of DNA are identified in clinical specimens with high sensitivity of identifying Chlamydia infections and avoids false positive results.

Standard testing today utilizes polymerase chain reaction technology for identification of Chlamydia.

One of the most common infectious causes of blindness.

Trachoma caused by repeated eye infections with serovars of A-C Chlamydia trachomatis.

Trachoma initial signs are non-specific dilation of conjunctival blood vessels after an incubation period of 5-10 days.

Azithromycin is the treatment of choice for ocular infection with chlamydia trachomatis.

Azithromyciin is an essential component of the global elimination program.


Recommended treatment for chlamydia is 100 mg of doxycycline oraly twice daily for seven days.

Alternative regimens include azithromycin or levofloxacin.

All sex partners within the last 60 days of an individuals chlamydia diagnosis should be treated presumptively.

First line treatment for lymphogranuloma  venereum is doxycycline.



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