2013-08-20
Diagnosis and Treatment of Chlamydia
Chlamydia is an obligate intracellular bacterium that relies on host cells for energy and can only grow within living tissue cells. It is a non-motile Gram-negative bacterium. The incubation period is uncertain, ranging from 7 to 14 days or longer. Clinical symptoms may appear several weeks later, including pelvic inflammation, pelvic adhesions, ectopic pregnancy, and infertility. Chlamydia infection is very common, and even after being cured, re-infection is possible. There is no immunity against Chlamydia, and there is no vaccine available for prevention. Patients need to receive treatment before engaging in sexual activity again.
For clinical testing of Chlamydia, according to the recommendations of the Centers for Disease Control and Prevention (CDC) in the United States, nucleic acid amplification tests (NAATs) are the most accurate and cost-effective diagnostic method, and the specimen can be self-collected by the patient. In Taiwan, the Centers for Disease Control (CDC) recommends clinical testing for Chlamydia using endocervical or cervical swabs, employing direct immunofluorescence staining or cell culture to detect the presence of the bacteria inside the cells. General laboratories often use serum testing for the presence of Chlamydia-specific antibodies (IgM, IgG, IgA) to determine infection status. The advantages of serum testing are convenience of specimen collection (requiring only a venous blood sample) and high specificity. However, a limitation is that individuals who have previously been infected with Chlamydia and subsequently cured may still have IgG antibodies present in their body.
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Item
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Timing of Appearance
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Clinical Significance
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Clinical Use
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IgG
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Appears 6-8 weeks after initial infection and remains present in the body for several decades even after recovery. | Past infection | Screening |
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IgM
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Appears 2-3 weeks after initial infection and gradually disappears after 6 weeks. | Indicator of acute phase | Used for diagnosing initial infection |
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IgA
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Indicates ongoing Chlamydia infection. IgA antibodies disappear approximately one week after the elimination of the infection agent. | Persistent or recurrent infection | Chronic or persistent infection |
| Direct immunofluorescence staining (endocervical/cervical swabs) | Can detect the presence of the bacteria, indicating an ongoing Chlamydia infection. | Highest sensitivity and specificity, but expensive. | Direct evidence of Chlamydia presence |
| NAATs (endocervical/cervical swabs, urine) | Can detect the presence of bacterial nucleic acid, indicating an ongoing Chlamydia infection. | Highest sensitivity and specificity | Direct evidence of Chlamydia presence |
Treatment for Chlamydia follows the recommendations of the Taiwan Centers for Disease Control, which include three options:
（1）Azithromycin 1 gm taken orally as a single dose.
（2）Tetracycline 500 mg taken orally every 6 hours for 7 consecutive days.
（3）Doxycycline 100 mg taken orally twice daily for 7 consecutive days.
All three treatment regimens achieve 100% efficacy, but only azithromycin is recommended for pregnant patients.
AnAn Reproductive Medical Center includes Chlamydia screening as a routine test. Women undergoing assisted reproductive treatment are required to undergo Chlamydia IgG testing (or endocervical/cervical swab NAATs) to detect the presence of the bacteria in their blood. If a positive reaction is observed, medication treatment is provided, and additional Chlamydia IgA testing is conducted. The partner is also advised to undergo Chlamydia IgG testing to minimize the impact caused by Chlamydia infection.