Infections caused by C. trachomatis (CT) and N. gonorrhoeae (NG)are two of the most common sexually transmitted diseases (STD) in the United States and worldwide. Each may cause asymptomatic infections, compounding the problem of diagnosis and contributing to the spread of disease. The application of sensitive and specific screening methods for the diagnosis of CT and GC infection is an important tool for controlling the spread of these organisms and reducing the serious complications of untreated disease.
There has been a revolution in diagnostic methodology in recent years with the introduction of nucleic acid testing. Estimates of prevalence of infection determined in the past by tissue culture or antigen detection methods were gross underestimates. NAAT offers the highest sensitivity: 96-99% for CT and NG, and highest specificity: 96-99% for CT and NG. Nucleic acid amplification tests (NAAT) have consistently exceeded the sensitivities and specificities of non-NAAT methods (culture and indirect fluorescent antibody testing) in the detection of these organisms. The CDC, therefore, recommends use of a NAAT to screen for genitourinary infection with CT and GC. At JMMC, the Roche Cobas Amplicor is employed for the detection of CT and NG by PCR. Acceptable specimens include female endocervical swabs, urine or ThinPrep Pap Test specimens and male urethral swabs or urine specimen.
Genital infection with Chlamydia is the most common bacterial STD in the U.S. and is responsible for about 40% of nongonococcal urethritis in men. In women, genital chlamydial infections are a major cause of pelvic inflammatory disease (PID), which is an important cause of chronic pelvic pain, ectopic pregnancy, and infertility. Perinatal transmission of C.trachomatis to infants can cause neonatal conjunctivitis and pneumonia. Since infections in women and men are asymptomatic, rapid and accurate laboratory diagnosis is important for optimal management of infection in patients and for the interruption of transmission to contacts.
Gonorrhea is an important cause of urethritis in men and cervicitis in women. Approximately 20% to 40% of pelvic inflammatory disease and 14% of tubal infertility can be attributed to gonococcal infections. Additionally, 30-50% of men and women with gonococcal disease are co-infected with C.trachomatis. Therefore, laboratory tests designed to simultaneously detect C.trachomatis and N. gonorrhoeae from a single amplification reaction offer a distinct advantage.