Sexually Transmitted Infections: Chlamydia Trachomatis

Introduction

• Description: The most common bacterial sexually transmitted infection (STI) is that caused by Chlamydia trachomatis. More common than Neisseria gonorrhoeae by 3-fold, infections caused by C. trachomatis can be the source of significant complications and infertility.

• Prevalence: 20% of pregnant patients and 30% of sexually active adolescent women. Up to 40% of all sexually active women have antibodies, suggesting prior infection. In 2019 a total of 1,808,703 cases of C. trachomatis infection were reported to the Centers for Disease Control and Prevention (CDC) from 50 states and the District of Columbia (694/100,000 females, an increase of 10% from 2015.).

• Predominant Age: 15–30 years (85%), peak age 15–24 years (61% of cases). The CDC recommends screening all sexually active women younger than 26 years.

  

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: Infection by the obligate intracellular organism C. trachomatis. Chlamydia has a long incubation period (average, 10 days) and may persist in the cervix in a carrier state for many years.

• Risk Factors: The risk of contracting chlamydial infection is five times greater with three or more sexual partners and four times higher for patients using no contraception or nonbarrier methods of birth control. Other factors are age younger than 26 years, new partner within the preceding 3 months, other STIs, vaginal douching.

Signs and Symptoms

• Frequently asymptomatic (85%)

• Cervicitis; pelvic inflammatory disease (PID); lymphogranuloma venereum (much less common)

• Urethritis; pyuria without bacteriuria (25%)

• Less common: nongonococcal urethritis and inclusion conjunctivitis

• Eversion of the cervix with mucopurulent cervicitis supports the diagnosis but not pathognomonic

Diagnostic Approach