The Centers for Disease Control and Prevention (CDC) recently released updated guidelines for the prevention and treatment of sexually transmitted diseases (STDs).¹ These guidelines were developed through a systematic review of evidence that has become available since the 2002 guidelines were issued, as well as through expert consultation.

Health Education

Education and counseling are the main strategies in the prevention and control of STDs. Evaluation includes addressing key areas of sexual health referred to as the Five P's: Partners, Prevention of pregnancy, Protection from STDs, Practices, and Past history of STDs. Addressing this information with patients creates an opportunity for physicians to provide counseling and education while taking into account each patient's individual risk factors and goals. The use of motivational interviewing focuses on the specific behaviors of the patient and places a greater emphasis on moving toward individually defined, achievable, risk-reduction goals. Table 1¹ lists symptoms and diagnoses of selected STDs.

A visit with a physician for the screening, diagnosis, or treatment of STDs also provides an opportunity for the physician to educate the patient about human immunodeficiency virus (HIV). Patients may not be aware that the presence of an STD may facilitate the transmission of HIV if they are exposed to the virus. Because some patients who are HIV positive are unaware of their diagnosis, the CDC now encourages HIV screening for patients in all health care settings. Although patients may choose not to be tested, written consent for testing is no longer recommended (unless mandated by the state).²

Chlamydia Trachomatis

Chlamydia trachomatis is the most common reportable infectious disease in the United States, with almost 1 million cases reported in 2004.³ Few recommendations have changed for the treatment of persons infected with C. trachomatis; however, azithromycin (Zithromax) is now recommended as a primary, rather than alternative, treatment in pregnant women (Table 2).¹ This change occurred because of recent evidence supporting azithromycin as safe and effective during pregnancy.^4–6

Neisseria Gonorrhoeae

Since the publication of the 2002 STD treatment guidelines, the rate of quinolone-resistant Neisseria gonorrhoeae has continued to increase throughout the United States. As resistance increases, recommendations continue to change. Previous recommendations focused on the high levels of resistance in areas of Asia and the Pacific, California, Hawaii, and in some specific populations in the United States (e.g., men who have sex with men). In 2004, 6.8 percent of isolates collected by the CDC's Gonococcal Isolate Surveillance Project were resistant to ciprofloxacin (Cipro); when samples from California and Hawaii were excluded, 3.6 percent of isolates were resistant.⁷

Quinolone-resistant N. gonorrhoeae is more common in men who have sex with men than in men who have sex exclusively with women (23.8 versus 2.9 percent, respectively)⁷; however, the rate of quinolone-resistant N. gonorrhoeae continues to increase among heterosexual persons. In heterosexual men, the prevalence rose from 0.9 percent in 2002 to 3.8 percent in 2005,⁸ and preliminary data from the first six months of 2006 indicate an increase to 6.7 percent.⁹ Current guidelines reflect these changes (Table 3¹ ) by no longer recommending quinolones as treatment for N. gonorrhoeae infection.⁹

Expedited Partner Treatment

It is standard practice to recommend that sex partners of patients diagnosed with an STD be treated to decrease the risk of reinfection and to decrease the incidence and prevalence of STDs among social networks. The primary goal is for the patient's sex partners to be seen by a physician for testing, treatment, and education. However, there may be clinical situations in which this cannot be accomplished (e.g., because of patient, partner, or resource limitations). In these circumstances, the CDC recommends that physicians consider using expedited partner treatment.

Expedited partner treatment is the practice of treating sex partners of persons diagnosed with an STD without medical evaluation or prevention counseling; this is usually done by providing the patient with appropriate treatment to give to his or her partner. Three randomized controlled trials sponsored by the CDC evaluated the behavioral and clinical outcomes of expedited partner treatment compared with traditional treatment programs through patient or physician referral. In summary, the evidence supports expedited partner treatment as an option in patients with N. gonorrhoeae or C. trachomatis infection^10–12; however, it is important for physicians to be aware of their state's legal provision for this practice.

Trichomoniasis

Since publication of the 2002 STD treatment guidelines, options for the diagnosis and treatment of trichomoniasis have continued to improve. Tinidazole (Tindamax), a nitroimidazole that is similar to metronidazole (Flagyl), has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of trichomoniasis. A review of randomized controlled trials suggests that tinidazole is equivalent or superior to metronidazole, with the recommended metronidazole regimen resulting in cure rates of 90 to 95 percent and the recommended tinidazole regimen resulting in cure rates of 86 to 100 percent (Table 4¹ ).^1,13 Additionally, it is estimated that approximately 2.5 to 5 percent of Trichomonas vaginalis isolates now show some level of resistance to metronidazole.^1,14 Tinidazole has a higher serum half-life and better penetration into the genitourinary tissues,^15,16 which suggests that it is a potential treatment for metronidazoleresistant trichomoniasis.^14,17,18

Diagnostic options for trichomoniasis have also expanded. Although the most common diagnostic method for trichomoniasis involves microscopy of vaginal secretions, the sensitivity of this method is only 60 to 70 percent. Additional FDA-approved, point-of-care tests include the Osom Trichomonas Rapid Test, which uses immunochromatographic capillary flow dipstick technology, and the BD Affirm VPIII Microbial Identification Test, which is a nucleic acid probe test. Both have a sensitivity of more than 83 percent and specificity of more than 97 percent; however, false-positive results are a concern in areas of low disease prevalence.¹

Genital Herpes Simplex Virus

Most persons infected with genital herpes simplex virus (HSV) do not show clinical signs of disease. However, antiviral treatments for persons with clinical symptoms provide some symptomatic relief, as well as a lower viral burden and potential for transmission. Additional alternatives for episodic treatment of recurrent genital HSV require a shorter duration of treatment (one or two days of treatment versus five days of treatment) (Table 5¹ ). Suppressive therapy can reduce genital HSV recurrences by 70 to 80 percent in patients with at least six recurrences per year¹; however, in the revised guidelines, there is greater emphasis on the use of suppressive therapy to reduce disease transmission. One study of daily treatment with 500 mg of valacyclovir (Valtrex) decreased the rate of viral transmission in heterosexual partners.¹⁹ Patients wi Table 5

Type	Agent	Dosage
First clinical episode	Acyclovir (Zovirax)	400 mg orally three times daily for seven to 10 days
			or
		200 mg orally five times daily for seven to 10 days
	Famciclovir (Famvir)	250 mg orally three times daily for seven to 10 days
	Valacyclovir (Valtrex)	1 g orally twice daily for seven to 10 days
Episodic therapy for recurrent genital herpes	Acyclovir	400 mg orally three times daily for five days
			or
		800 mg orally twice daily for five days
			or
		800 mg orally three times daily for two days
	Famciclovir	125 mg orally twice daily for five days
			or
		1 g orally twice daily for one day
	Valacyclovir	500 mg orally twice daily for three days
			or
		1 g orally once daily for five days
Suppressive therapy for recurrent genital herpes	Acyclovir	400 mg orally twice daily
	Famciclovir	250 mg orally twice daily
	Valacyclovir	500 mg orally once daily*
			or
		1 g orally once daily

*— This dosage may be less effective than other valacyclovir or acyclovir dosing regimens in patients with frequent recurrences (more than 10 per year).

Information from reference ¹ .

th HSV are encouraged to consider suppressive treatment as part of the overall strategy in reducing transmission, regardless of the number of recurrences per year.

Syphilis

Rates of primary and secondary syphilis increased for the fifth consecutive year in 2005 (8,176 cases reported) to their highest levels since 1997.¹ Penicillin G benzathine continues to be the primary antibiotic treatment recommended (Table 6¹ ). The CDC guidelines also include a discussion of treatment with doxycycline (Vibramycin), tetracycline, and ceftriaxone (Rocephin) in patients who are allergic to penicillin. The use of azithromycin is also discussed. Although earlier studies suggested that azithromycin given as a single 2-g dose might be effective,^20,21 several cases of treatment failure, as well as reported cases of isolate resistance have been noted, suggesting that close follow-up is needed if azithromycin is used.²²

Lymphogranuloma Venereum

Lymphogranuloma venereum (LGV) is caused by C. trachomatis serovars L1, L2, or L3. Although still relatively uncommon in the United States and in western European countries, a significant increase in cases was noted in the Netherlands in 2004 among men who have sex with men.²³ The CDC addresses this concern by adding information to the guidelines about the clinical presentation of LGV. Presentation can include a nontender papule that may ulcerate after three to 30 days at the site of inoculation, and signs of proctocolitis (e.g., mucoid or hemorrhagic discharge, anal pain, constipation, fever or tenesmus) in persons with a history of rectal exposure to the bacteria. These symptoms in at-risk patients should prompt further diagnostic and treatment consideration. Diagnosis is primarily clinical because culture and nucleic acid amplification testing are not specific for LGV caused by C. trachomatis. If a patient has symptoms and specific typing is desired, contact with state or local health departments is often required. The CDC continues to recommend a three-week course of doxycycline when symptoms or testing suggest LGV, although erythromycin is an alternative (Table 7¹ ).