Sexually transmitted diseases (STDs) collectively describe a wide range of infections that are acquired through sexual contact and have a major impact on public health and the utilization of health care resources.1 Sexually transmitted diseases are associated with symptomatic disease, infertility, and deleterious effects on pregnancy and childbirth, among other complications.1,2 Approximately 19 million new STD cases occur annually, almost half of these cases occurring in patients 15 to 24 years of age.3 The estimated annual cost of STDs to the US health care system was over $15 billion in 2007.1
Four major STDs will be reviewed in this chapter: chlamydia, gonorrhea, genital herpes, and syphilis.
Chlamydial genital infection is the most frequently reported infectious disease in the United States, with highest prevalence in persons aged 25 or younger.1,2 Chlamydial genital infection is caused by Chlamydia trachomatis, an obligate intracellular pathogen and the most common bacterium responsible for STDs.4 Infection is transmissible through vaginal, anal, or oral sex.
Chlamydia typically manifests as cervicitis in women and urethritis in men; however, asymptomatic infection is common, occurring in up to 70% of women and 50% of men.2,4 In symptomatic disease, women may present with mucopurulent vaginal discharge, postcoital bleeding, and urethral infection.4 Symptoms in men include dysuria and urethral discharge.4 Without appropriate and timely treatment, complications such as pelvic inflammatory disease (PID), ectopic pregnancy, premature delivery, and infertility can result.2,5
A number of testing methods are available for diagnosis of chlamydia including cell culture, antigen-based tests, molecular methods such as nucleic acid hybridization (DNA probing), and nucleic acid amplification tests (NAATs).4 Nucleic acid amplification tests have become the tests of choice for diagnosing chlamydial genital infection due to their high sensitivity and specificity and FDA-cleared use for a wide range of specimen types.2,4
Gonorrhea is the second most commonly reported bacterial STD, with an estimated 600,000 new cases each year.2 Infection risk is highest in women younger than 25 years of age.2 Infection is caused by Neisseria gonorrhoeae, a gram-negative Diplococcus, and is transmissible through contact with genitals, mouth, or anus. After contact is made, the organism attaches to mucosal epithelium causing a strong neutrophil response with pus production.6
Gonococcal infection typically causes cervicitis in women and urethritis in men.7 In men, symptoms include dysuria and urethral discharge which becomes purulent within days.6 Because of the early presentation and discomfort associated with symptoms in men, treatment is often sought early enough to prevent complications.2 Women with gonorrhea are generally asymptomatic or have only minor symptoms.2,6 Symptoms usually occur within 10 days in those who develop them and include vaginal discharge, dysuria, and vaginal bleeding (sometimes ...