Chlamydia trachomatis infections

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Rates of chlamydia infection have doubled in the last decade. Adherence to screening guidelines for the infection is important for identifying cases, initiating treatment, and reducing maternal and neonatal morbidity



CASE Pregnant woman with symptoms of genital infection

A 23-year-old primigravid woman at 15 weeks and 2 days’ gestation reported having a 2-week history of increased urinary frequency and vaginal discharge. She said she experienced similar symptoms 6 weeks previously that resolved within a week. The patient has had 3 sexual partners in the past year. Her current partner was experiencing a yellow urethral discharge and dysuria. On the patient’s speculum examination, the clinician noted a yellow-green discharge emanating from the cervix as well as cervical motion tenderness.

What is the most likely diagnosis, and how would you treat this patient?

The culprit was chlamydia

Chlamydia trachomatis is an obligate intracellular bacterium that does not stain with Gram staining. A rigid cell wall encloses its intracellular component. C trachomatis infection begins when the chlamydial elementary body enters a susceptible host cell.

Once ingested, the organism’s surface antigens (major outer membrane protein and lipopolysaccharide antigens) provide intracellular sanctuary for the bacterium by inhibiting phagolysosomal fusion. Subsequently, the elementary body morphs into a reticular body, which replicates through adenosine triphosphate (ATP)–dependent binary fission. After approximately 48 hours of replication, the organism again morphs into an elementary body and is released to infect additional cells and acquire new ATP stores for further replication.

Chlamydia can be transmitted horizontally during oral, vaginal, or anal intercourse or vertically to the infant during vaginal delivery.

The US’s most common notifiable disease

According to the Centers for Disease Control and Prevention (CDC), the incidence of chlamydia infection in the United States increased considerably in recent years: from 976,455 cases in 2005 to 1,758,668 cases in 2018.1 In 2018, rates of chlamydia infection in women were nearly double the rates in men, with an incidence of 688.2 versus 377.5 per 100,000 cases, and a prevalence of 1,150,672 versus 612,020.1

Young adults have a higher frequency of chlamydia infection than any other age group. From 2017 to 2018, reported cases in women aged 15–19 years increased by 1.3%, to 3,306.8 per 100,000; in women aged 20–24 years, cases increased by 0.8%, to 4,064.6 per 100,000. In young men in the same age ranges, reported cases increased by 3.7%, to 959.0 cases per 100,000, and by 3.3%, to 1,784.5 per 100,000 cases, respectively.1

Both the incidence and prevalence of chlamydia infection are higher in African Americans than in whites, while Asians have the lowest rates.1 The prevalence of infection also is increased with incarceration, lower socioeconomic status, and residence in the southern United States.

The prevalence of chlamydia infection in pregnant women is approximately 2% to 3%, but it may be as high as 30% in high-risk populations, such as women who are unmarried, have multiple sex partners, are coinfected with another sexually transmitted disease (STD), have partners with nongonococcal urethritis, have mucopurulent discharge, have acute urethral syndrome, and have late or no prenatal care.2 Since chlamydia infection often is asymptomatic and some infections resolve spontaneously, the true prevalence of infection probably is underreported.

Continue to: Chlamydia infection can cause serious clinical manifestations...


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