Sexually-transmitted infections (STIs) constitute a major health burden in the U.S., and reported incidence among adolescents is increasing. These diseases are frequently asymptomatic and are most often caused by viruses or bacteria.

• Most-common viral STIs
  • Human immunodeficiency virus (HIV)
  • Herpes simplex virus
  • Human papillomavirus
• Most-common bacterial STIs
  • Chlamydia trachomatis

    Epidemiology Incidence – 496.5/100,000 females (2008); most common reportable STI in U.S. and worldwide Age – highest incidence is 15-25 years Gram-negative obligate intracellular parasite Risk Factors Multiple sex partners (≥2) Non-Caucasian Younger age (<25 years) Coinfection with gonorrhea or HIV Non-use of barrier methods Previous history of STI Clinical Presentation Asymptomatic in >50% of infected patients Urethritis, salpingitis, epididymo-orchitis Oropharyngeal disease Pelvic inflammatory disease (PID) Infection during pregnancy Premature rupture of membranes Preterm delivery Low birth weight Neonatal conjunctivitis Neonatal pneumonia Complications Ectopic pregnancy Tubal factor infertility

    Bacterial vaginosis (BV)

    Epidemiology Prevalence – 16% of pregnant women; most common form of vaginitis (50% of women with BV are asymptomatic) Caused by a combination of Gardnerella vaginalis with anaerobic bacteria overgrowth at the expense of commensal lactobacilli Polymicrobial Risk Factors Douching Non-use of barrier methods Multiple sex partners (>2) Non-Caucasian Clinical Presentation Malodorous vaginal discharge (fishy odor) Vulvovaginitis, cervicitis, salpingitis Infection during pregnancy Increased risk of HIV infection Preterm labor Premature rupture of membranes Postpartum endometriosis

    Neisseria gonorrhoeae

    Epidemiology Incidence – 118.9/100,000 in 2007 (U.S.) Age – highest incidence is 15-25 years Nonmotile gram-negative diplococcus Risk Factors Multiple sex partners (>2) Non-Caucasian Younger age (<25) Coinfection with HIV Non-use of barrier methods Previous history of STI Douching Clinical Presentation Cervicitis, urethritis, salpingitis PID Oropharyngeal disease Neonatal infection

  • Treponema pallidum (syphilis)
• Most-common parasitic/protozoan STI
  • Trichomonas vaginalis

    Epidemiology Prevalence – 7 million cases annually in U.S. Age – highest incidence is 30-50 years  Flagellated protozoan Risk Factors Multiple sex partners (>2) Non-Caucasian Coinfection with gonorrhea or HIV Non-use of barrier methods Previous history of STI Infected with HIV Clinical Presentation Up to 50% of women with T. vaginalis infections have minimal or no symptoms If symptomatic, T. vaginalis infections can cause vaginitis, urethritis, and cervicitis May present with vaginal, malodorous discharge, strawberry cervix, dysuria, and vulvar irritation (accounts for 15-20% of cases of vulvovaginitis) Pregnant females Increased risk of HIV transmission Preterm labor Premature rupture of membranes Low birth weight

Treatment

• CDC recommends treatment of all STIs (see treatment guidelines )
  • Treatment of infected patient’s partner(s) is also recommended
  • Treatment of STIs should include specific therapy for gonococcus
  • Empiric treatment for pelvic inflammatory disease in sexually active young women (≤25 years) and other women at high risk of STI (eg, multiple sex partners or history of STI) with symptoms including pelvic pain, post coital bleeding, fever, intermenstrual bleeding

Indications for Testing

• Cervicitis, urethritis, pelvic inflammatory disease

Criteria for Diagnosis

• Amsel criteria for bacterial vaginosis (BV) – three of four criteria should be met
  • Thin watery discharge
  • Vaginal pH>4.5
  • Fish odor to discharge when 10% potassium hydroxide (KOH) applied
  • Clue cells under microscopic examination (>20% of vaginal epithelial cells)

Laboratory Testing

• Microscopy
  • Wet mount – protozoa indicate trichomoniasis; clue cells indicate BV
    • Cornerstone of diagnostic evaluation of vaginal discharge
  • KOH – presence of hyphae indicates yeast
  • Gram stain – use for gonorrhea in patients with discharge
  • DFA – chlamydia
• Nucleic acid amplification testing (NAAT) of urine, urethra, cervical/vaginal swabs
  • Recommend concurrent testing for gonorrhea and chlamydia
  • NAAT methodology is standard of care for diagnosis of chlamydia
• Culture
  • May be useful in gonorrhea, BV, chlamydia, trichomoniasis
  • Historically considered gold standard
  • May be required in certain clinical contexts for diagnosing Chlamydia trachomatis and Neisseria gonorrhoeae to meet applicable laws and regulations
• Other testing
  • DNA probe – gonorrhea, chlamydia
    • Not recommended – less sensitive than amplification-based methods

Differential Diagnosis

• Urinary tract infection
• Vaginitis/cervicitis
• Vulva, vaginal candidiasis
• Malignancy – ovarian cancer, cervical cancer
• Nephrolithiasis
• Ectopic pregnancy
• Diverticulitis
• Inflammatory bowel disease
• Appendicitis
• Pregnancy
• Ovarian cyst

• STI screening recommendations for women
  • Screening recommendations for sexually active nonpregnant women

    Screening Recommendations for Sexually Active Nonpregnant Women
    STI	USPSTF	CDC	AAFP	ACOG
    Chlamydia	Yearly screening – screen women <25 years and others at increased risk* Do not screen women >25 years and not at high risk	Screen women ≤25 years and others at increased risk***	Screen women ≤25 years and others at increased risk*	Screen women ≤25 years and others at increased risk****
    Gonorrhea	Screen women <25 years and others at increased risk* No recommendation for or against screening women not at risk and >25 years	Screen women at increased risk*** Do not screen general population	Screen women <25 years and others at increased risk*	Screen adolescents and others at increased risk****
    Syphilis	Screen women at increased risk**	Screen women exposed to syphilis	Screen women at increased risk*	Screen women at increased risk****
    HIV	Screen women at increased risk*	Screen all patients 13-64 years regardless of risk factors	Screen women at increased risk*	Screen women at increased risk****
    Hepatitis B	Do not screen general population	Provide prevaccination screening for women at increased risk***	Do not screen general population	No specific recommendation
    Hepatitis C	Do not screen general population; insufficient evidence to recommend for or against screening women at increased risk	Screen women at increased risk*** Do not screen general population	Do not screen general population; insufficient evidence to recommend for or against screening women at increased risk*	Screen women at increased risk****
    HSV	Do not screen asymptomatic patients	Do not screen general population	Do not screen general population	Screen if sexual partner has HSV
    HPV	Insufficient evidence to use as primary screening test for cervical cancer	Do not screen for subclinical infection	Insufficient evidence to use as primary screening test for cervical cancer	Testing with a Pap smear is an option for women >30 years
    Bacterial vaginosis	Do not screen	No recommendation	No specific recommendations	No specific recommendations
    STI = sexually transmitted infection; USPSTF = U.S. Preventive Services Task Force; CDC = Centers for Disease Control and Prevention; AAFP = American Academy of Family Physicians; ACOG = American College of Obstetricians and Gynecologists; HIV = human immunodeficiency virus; HSV = herpes simplex virus; HPV = human papillomavirus; Pap = Papanicolaou * At risk = new or multiple partners; diagnosis of gonorrhea or chlamydia within the last 12 months; those not consistently using barrier methods; those having sex under the influence of drugs ** Commercial sex workers; persons who exchange drugs for sex; incarceration in adult correctional facility; multiple sex partners *** Increased risk defined as <25 years with inconsistent condom use; history of other STIs; multiple sex partners or drug use **** High-risk factors = history of multiple sexual partners or a sexual partner with multiple contacts; sexual contact with individuals with a culture-proven STI; history of repeated episodes of STIs; attendance at clinics for STIs

  • Screening recommendations for pregnant women

    Screening Recommendations for Pregnant Women
    STI	USPSTF	CDC	AAFP	ACOG
    Chlamydia	Screen women <25 years and others at increased risk*	Screen all sexually active females ≤25 years and those >25 who are at risk**	Screen women ≤25 years and others at increased risk*	Screen women at increased risk***
    Gonorrhea	Screen women <25 years and others at increased risk*	Screen women at increased risk**	Screen women at increased risk*	Screen women at increased risk***
    Syphilis	Screen all	Screen all	Screen all	Screen all
    HIV	Screen all	Screen all	Screen all	Screen all
    Hepatitis B	Screen all	Screen all	Screen all	Screen all
    Hepatitis C	No specific recommendation	Screen women at increased risk**	No specific recommendation	Screen women at increased risk***
    HSV	Do not screen asymptomatic patients	No specific recommendation	Do not screen general population	No specific recommendation
    HPV	No specific recommendation	No specific recommendation	No specific recommendation	No specific recommendation
    Bacterial vaginosis	Do not screen for low-risk patients; insufficient evidence to recommend screening in patients at high risk for preterm delivery	No specific recommendation	Do not screen for low-risk patients; insufficient evidence to recommend screening in patients at high risk for preterm delivery	No specific recommendation
    STI = sexually transmitted infection; USPSTF = U.S. Preventive Services Task Force; CDC = Centers for Disease Control and Prevention; AAFP = American Academy of Family Physicians; ACOG = American College of Obstetricians and Gynecologists; HIV = human immunodeficiency virus; HSV = herpes simplex virus; HPV = human papillomavirus; Pap = Papanicolaou * At risk = new or multiple partners; diagnosis of gonorrhea or chlamydia with last 12 months; those not consistently using barrier methods; those having sex under the influence of drugs ** Increased risk = defined as <25 years with inconsistent condom use; history of other STIs; multiple sex partners or drug use *** High-risk factors = history of multiple sexual partners or a sexual partner with multiple contacts; sexual contact with individuals with a culture-proven STI; history of repeated episodes of STIs; attendance at clinics for STIs

• STI screening recommendations for men
  • USPSTF
    • No screening if not engaging in high-risk behaviors
    • If engaging in high-risk behaviors, screen for syphilis and HIV
  • CDC
    • Screen all men for HIV who seek medical care
    • Men who have sex with men are at risk – test for rectal and urethral gonorrhea and pharyngeal chlamydia annually

Tests generally appear in the order most useful for common clinical situations

Guidelines

• Geisler WM. Management of uncomplicated Chlamydia trachomatis infections in adolescents and adults: evidence reviewed for the 2006 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines. Clin Infect Dis. 2007; 44 Suppl 3 :S77-S83.PubMed
• Kropp RY, Latham-Carmanico C, Steben M, Wong T, Duarte-Franco E. What's new in management of sexually transmitted infections? Canadian Guidelines on Sexually Transmitted Infections, 2006 Edition. Can Fam Physician. 2007; 53 (10) :1739-1741.PubMed
• McLean CA, Stoner BP, Workowski KA. Treatment of lymphogranuloma venereum. Clin Infect Dis. 2007; 44 Suppl 3 :S147-S152.PubMed
• Meyers DS, Halvorson H, Luckhaupt S. Screening for chlamydial infection: an evidence update for the U.S. Preventive Services Task Force. Ann Intern Med. 2007; 147 (2) :135-142.PubMed
• Newman LM, Moran JS, Workowski KA. Update on the management of gonorrhea in adults in the United States. Clin Infect Dis. 2007; 44 Suppl 3 :S84-101.PubMed
• Screening for chlamydial infection: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2007; 147 (2) :128-134.PubMed
• USPSTF Recommendations for STI Screening. Agency for Healthcare Research and Quality. Rockville: Maryland [Accessed: 20 Apr 2009] 
• Workowski KA, Berman S. Sexually Transmitted Diseases Treatment Guidelines, 2010. Centers for Disease Control and Prevention. December 17, 2010 / 59(RR12);1-110. [Accessed: 22 Dec 2010] 

General

• Denney JM, Culhane JF. Bacterial vaginosis: a problematic infection from both a perinatal and neonatal perspective. Semin Fetal Neonatal Med. 2009; 14 (4) :200-203.PubMed
• Frenkl TL, Potts J. Sexually transmitted infections. Urol Clin North Am. 2008; 35 (1) :33-46.PubMed
• Gaydos CA, Ferrero DV, Papp J. Laboratory aspects of screening men for Chlamydia trachomatis in the new millennium. Sex Transm Dis. 2008; 35 (11 Suppl) :S45-S50.PubMed
• Greer L, Wendel GD Jr. Rapid diagnostic methods in sexually transmitted infections. Infect Dis Clin North Am. 2008; 22 (4) :601-17, v.PubMed
• Huppert JS. Trichomoniasis in teens: an update. Curr Opin Obstet Gynecol. 2009; 21 (5) :371-378.PubMed
• Quan M. Vaginitis: diagnosis and management. Postgrad Med. 2010; 122 (6) :117-127.PubMed
• Rosenvinge MM, Lau R. Screening for asymptomatic chlamydia in women--how often would gonorrhoea be missed?. Int J STD AIDS. 2009; 20 (8) :571-572.PubMed
• Trigg BG, Kerndt PR, Aynalem G. Sexually transmitted infections and pelvic inflammatory disease in women. Med Clin North Am. 2008; 92 (5) :1083-113, x.PubMed
• Verstraelen H, Verhelst R. Bacterial vaginosis: an update on diagnosis and treatment. Expert Rev Anti Infect Ther. 2009; 7 (9) :1109-1124.PubMed
• Wright HR, Turner A, Taylor HR. Trachoma. Lancet. 2008; 371 (9628) :1945-1954.PubMed

Cervical Cancer
Herpes Simplex Virus
Human Immunodeficiency Virus
Human Papillomavirus
Ovarian Cancer
Septic Arthritis
Treponema pallidum
Yeast-Associated Infections