Sexually Transmitted Infections, Bacteria

Sexually Transmitted Infections, Bacteria

 

Sexually-transmitted infections (STIs) constitute a major health burden in the U.S.; reported incidence among adolescents is increasing, and these diseases are frequently asymptomatic.

For information regarding HSV, HPV and HIV, refer to specific topic in ARUP Consult®

  • Most common STIs
    • Bacterial infections
      • Chlamydia trachomatis
      • Neisseria gonorrhea
      • Trichomonas vaginalis
      • Bacterial vaginosis (BV) infection
      • Treponema pallidum (syphilis)
      • Refer to syphilis topic in ARUP Consult®
    • Viral infections
      • Human immunodeficiency virus (HIV)
      • Herpes simplex virus (HSV)
      • Human papilloma virus (HPV)

Bacterial infectious agents other than Treponema pallidum.

  • Chlamydia trachomatis
    • Epidemiology
      • Prevalence – >800,000 cases annually in U.S.
      • Age – highest incidence in 15-25 year olds
      • Organisms –  gram-negative obligate intracellular parasite
    • Risk Factors
      • Multiple sex partners
      • Non-Caucasian
      • Younger age
      • Coinfection with gonorrhea or HIV
      • Non-use of barrier methods
      • Previous history of STI
      • Infected with HIV
    • Clinical Presentation
      • Asymptomatic
      • Urethritis, cervicitis, salpingitis
      • Oropharyngeal disease
      • Pelvic inflammatory disease (PID)
      • Neonatal infection
    • Diagnosis
      • Laboratory testing
        • Nucleic acid amplification on urine, urethral or cervical/vaginal swabs
  • Neisseria gonorrhea
    • Epidemiology
      • Prevalence – >350,000 reported cases annually in U.S.
      • Age – highest in 15-25 year olds
      • Organism – nonmotile gram-negative diplococcus
    • Risk Factors
      • Multiple sex partners
      • Non-Caucasian
      • Younger age
      • Coinfection with gonorrhea or HIV
      • Non-use of barrier methods
      • Previous history of STI
      • Infected with HIV
    • Clinical Presentation
      • Cervicitis, urethritis, salpingitis
      • PID
      • Oropharyngeal disease
      • Neonatal infection
    • Diagnosis
      • Laboratory testing
        • Nucleic acid amplification on urine, urethral or cervical/vaginal swabs
        • Culture
  • Trichomonas vaginalis
    • Epidemiology
      • Prevalence – accounts for 15-20% of cases of vulvovaginitis
      • Age – highest in 15-25 year olds
      • Organism – flagellated protozoan
    • Risk Factors
      • Multiple sex partners
      • Non-Caucasian
      • Younger age
      • Coinfection with gonorrhea or HIV
      • Non-use of barrier methods
      • Previous history of STI
      • Infected with HIV
    • Clinical Presentation
      • Vulvovaginitis, cervicitis,urethritis
      • Copious pruritic discharge strawberry cervix
      • Pregnant females
        • Increased risk of HIV transmission
        • Preterm labor, premature rupture of membranes
        • Low birth weight
    • Diagnosis
      • Laboratory testing
        • Microscopy
          • Saline wet mount – motile protozoa seen 60-70% of the time
        • Other tests include DNA direct probe, point of care testing or cytologic exam
  • Bacterial vaginosis
    • Epidemiology
      • Prevalence – 16% of pregnant women
      • Organism
        • Gardnerella vaginalis – gram-variable nonmotile coccobacillus
          • Most common organism responsible for BV
        • Other agents include Mycoplasma hominis and Ureaplasma urealyticum
    • Risk Factors
      • Douching
      • Non-use of barrier methods
      • Multiple sex partners
      • Non-Caucasian
    • Clinical Presentation
      • Malodorous vaginal discharge
      • Vulvovaginitis, cervicitis, salpingitis
      • Pregnant females
        • Increased risk of HIV transmission
        • Preterm labor
        • Premature rupture of membranes
        • Postpartum endometriosis
    • Diagnosis
      • Laboratory testing
      • Microscopy (KOH mount) – clue cells
      • Amsel criteria (three of four criteria should be met)
        • Thin watery discharge
        • Vaginal fluid pH>4.5
        • Fish odor to discharge when 10% KOH applied
        • Clue cells under microscopic examination
    • Current U.S. Preventative Services Task Force (USPSTF) for STI screening
      • Directed at three populations – non-pregnant women, pregnant women and men
      • Need to consider risk factors (both behavioral and demographic) that increase risk of STI to determine if screening is necessary
      • No guidelines for what ages to stop screening or how often to screen
      • Non-pregnant
        • If engaging in high-risk sexual behavior, screen for Chlamydia, gonorrhea, HIV and syphilis
        • If <25 years and non high risk, screen for Chlamydia and gonorrhea
      • Pregnant women
        • Screen all for hepatitis B, HIV and syphilis
        • If high risk, screen the same as for high risk non-pregnant women 
      • Men
        • No screen necessary if not engaging in high risk behaviors
        • If high risk behaviors, screen for HIV and syphilis

Click here for table of Comparisons of STI Screening Recommendations for Sexually Active Nonpregnant Women

Click here for table of Comparisons of STI Screening Recommendations for Pregnant Women


  • Treatment
    • Centers for Disease Control (CDC) recommends treatment of all STIs
      • Treatment of infected patient’s partner(s) is also recommended

See Also