Today, NAATs are the “expanded gold standard” for detecting C. trachomatis as well as N. gonorrhoeae. These tests offer increased sensitivity because they are able to produce a positive signal from a single copy of target DNA or RNA. In addition to being able to screen endocervical and urethral swabs, NAATs have been approved to test urine for gonorrhea and chlamydia in both males and females, eliminating the need for a pelvic examination or intraurethral swab specimen. 

One disadvantage to NAATs is the possibility of the specimen’s containing amplification inhibitors, which can result in a false-negative test. NAATs are also more susceptible than non-NAATs to cross-contamination in the laboratory. Although this test has been approved for urine specimens, the sensitivity is somewhat lower for urine compared with swab specimens; therefore, if a pelvic exam is scheduled, a cervical specimen should be obtained. Vaginal and ocular specimens have been tested and appear to yield accurate results; rectal and pharyngeal studies are ongoing. However, none of these sites is cleared for NAATs by the FDA at the present time.17

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Serology testing should not be used for uncomplicated genital infection because lasting antibodies cannot be easily distinguished from antibodies produced by a current infection.  

Treatment

Treating infected patients prevents transmission to their sexual contacts as well as subsequent sexual partners and prevents adverse sequelae. In pregnancy, treatment can prevent transmission to infants during birth. 

Doxycycline and azithromycin are the first-line treatments for chlamydial infections. Both are equally efficacious. Ideally, medications should be dispensed on-site, with direct observation of the first dose to maximize compliance with recommended regimens. If the patient has difficulty complying with a seven-day treatment regimen, a single-dose treatment of azithromycin may be an easier and more cost-effective option. Patients who are HIV-positive should be given the same treatment as those who are negative. Vaccines for prevention are not available at this time.

If a patient tests positive for chlamydia, all of his or her sexual partners during the past 60 days should be evaluated, tested, and treated. The most recent partner should be evaluated even if the last sexual contact occurred more than 60 days ago. It is important for patients to understand the risks of infection to their partner(s), even if they do not have symptoms. The absence of symptoms does not mean the absence of infection. 

Patients should receive specific instructions to abstain from oral, vaginal, penile, and/or anal contact until seven days after receiving a single-dose regimen or completing a seven-day course of treatment, their partner(s) have been treated, and all signs and symptoms have resolved.9

Follow-up

Retesting after completing treatment with doxycycline or azithromycin is not required unless symptoms persist, compliance with the medications is questioned, or reinfection is suspected. A test-of-cure may be considered if alternative regimens were used but should not be conducted for at least three weeks after treatment using non-culture tests because of the possibility of continued secretion of dead organism and resultant false-positive test. 

Because of high rates of recidivism related to reinfection as well as elevated risk of PID and other complications with subsequent infections, women and adolescents especially should be offered screening three months after treatment. This coincides with repeat HIV screening. Clinicians are also strongly encouraged to rescreen if patients present for care within the following 12 months, regardless of whether or not they believe their sex partner(s) were treated. A test-of-cure in pregnancy is recommended three weeks after treatment.9

Early detection and treatment is the most effective way to significantly reduce the impact and subsequent reproductive consequences of C. trachomatis infection. Recent technological advances, with improved sensitivities and ease of testing, will hopefully hasten efforts for evaluation in historically difficult populations.

Through increased awareness of this silent infection and continued integration of screening efforts, the long-term medical complications — including reduction in transmission and acquisition of HIV, adverse pregnancy outcomes, and neonatal infections — can hopefully be prevented.

Ms. Grimshaw-Mulcahy is a family nurse practitioner and assistant medical director of the Montefiore Medical Center STD Center for Excellence in Bronx, N.Y.

References

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4. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2004. Available at ww.cdc.gov/std/stats. Accessed February 10, 2006.
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7. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2003.
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14. Centers for Disease Control and Prevention (CDC). Chlamydia screening among sexually active young female enrollees of health plans — United States, 1999-2001. MMWR Morb Mortal Wkly Rep. 2004;53:983-985.
15. Chlamydia — CDC Fact Sheet.
16. Shafer MB, Tebb KP, Pantell RH, et al. Effect of a clinical practice improvement intervention on chlamydial screening among adolescent girls. JAMA. 2002:288;2846-2852.
17. Johnson RE, Newhall WJ, Papp, JR, et al. Screening tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae infections — 2002. MMWR Recomm Rep. 2002;51(RR-15):1-38.