Clinical Pearls & Morning Reports
Published February 22, 2017
Chlamydia is caused by the gram-negative bacterium Chlamydia trachomatis and is the most common infection reported in the United States, with more than 1.5 million cases reported in 2015. All sexually active women younger than 25 years of age and older women at risk for chlamydia should be offered chlamydia screening annually. Studies have supported benefits of chlamydia screening to prevent pelvic inflammatory disease. A new Review Article explains.
Q: Do current screening tests for chlamydial infection in women require an endocervical sample?
A: Screening women for chlamydia may be performed with the use of endocervical or vaginal samples or first-catch urine (the initial portion of the urinary stream) specimens. Women can undergo screening without a pelvic examination with the use of vaginal swabs or urine samples that they collect themselves. The Centers for Disease Control and Prevention (CDC) considers vaginal swabs to be the preferred specimen type, because nucleic acid amplification tests on vaginal swabs perform as well as those on cervical swabs, and collection of vaginal swabs is easy for most women to perform themselves. A first-catch urine specimen is also acceptable but may fail to detect up to 10% of infections. Home-based screening is also possible and is preferred by some women.
Q: Is repeat screening after treatment necessary when an initial screening test is positive?
A: Because reinfection is common (occurring in one in five women with chlamydial infection within 1 year after treatment) and is associated with increased risks for ectopic pregnancy and pelvic inflammatory disease, repeat screening 3 months after treatment is recommended to detect new infections.
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Figure 3. (10.1056/NEJMcp1412935/F3) Algorithm for Chlamydia Screening.
A: Women with chlamydial infection should be screened for other sexually transmitted diseases, including gonorrhea, syphilis, and HIV, if they have not been screened previously; hepatitis B vaccination should be considered for unvaccinated women, and human papillomavirus vaccination should be offered to age-appropriate candidates. Counseling on risk reduction should be addressed. Nearly 70% of male partners of women with chlamydial infection are also infected; therefore, sexual partners of persons who received a diagnosis of chlamydial infection should be screened and treated empirically if the sexual contact occurred within 60 days before the diagnosis or development of symptoms.
A: For reasons that remain unclear, declines in incidence have not been observed despite chlamydia screening programs. Although rates of pelvic inflammatory disease in the United States have declined in association with chlamydia screening, ectopic pregnancy rates have not. It is not known whether screening for C. trachomatis reduces the rate of HIV infection. Data are lacking on the benefits of shorter screening intervals and screening women at low risk. Data from trials evaluating the effect of screening men to reduce the rate of complications in women are also lacking, and routine screening of men is not recommended by the CDC. Screening at-risk, sexually active young men (e.g., men attending clinics for sexually transmitted diseases, incarcerated men, and at-risk men who have sex with men) should be considered. The recommendations of the CDC for women who have sex with women are the same as those for heterosexual women.