MicroBio Sexually Transmitted Infections

Vulvovaginal Candidiasis

Yeast, Candida albicans

Exudative

Vulvar itching, thick white discharge (“cottage cheese”), erythema

Vulvovaginal Candidiasis Diagnosis, Treatment, and Prevention

Microscopy of discharge, culture if necessary

Antifungal therapy (topical or systemic azole-class), supportive care

Avoid unnecessary antibiotics; glucose control in diabetics. In men, candida produce balance

Gonorrhea

Neisseria gonorrhoeae (Gram negative diplococcus)

Exudative

Men: Urethritis, purulent urethral discharge, dysuria; Women: Cervicitis, often asymptomatic

Can also affect other body parts depending on sexual contact: Proctitis, pharyngitis

Can infect neonates (ophthalmia, neonatorum); major STI with high rates of resistance

Gonorrhea Diagnosis, Treatment, and Prevention

NAAT (gold standard), culture if needed (differentiated medium)

Systemic antibacterial therapy (beta-lactam class); treat partners

Safer sex, screening in high-risk groups

Chlamydia (Serovars D-K)

Chlamydia trachomatis (obligate intracellular bacterium(

Exudative

Often asymptomatic (women). Cervicitis, urethritis, possible PID. Produce discharge, pelvic discomfort (women), and dysuria

Also produce postpartum endometriosis and conjunctivitis in newborns

Chlamydia (Serovars D-K) Diagnosis, Treatment, and Prevention

NAAT on urine or cervical/vaginal swabs

Antibacterial therapy (tetracycline-class or macrolide class), partner treatment

Screen sexually active young individuals; safer sex. Pregnancy

Trichomoniasis

Protozoan (Trichomonas vaginalis); motile = flagellated

Exudative

Frothy yellow-green discharge, pruritus, strawberry cervix (hemorrhages)

Trichomoniasis Diagnosis, Treatment, and Prevention

Wet mount microscopy; NAAT (most sensitive), check pH (really acidic)

Antiprotozoal therapy (nitromidazole-class), treat partners

Safer sex; partner treatment

Bacterial Vaginosis 

Polymicrobial imbalance: Gardnerella vaginalis + anaerobes (loss of lactobacilli)

Exudative

Thin gray discharge, fishy odor, pH > 4.5, clue cells

Bacterial Vaginosis Diagnosis, Treatment, and Prevention

Amsel criteria (positive in almost 3 test): Clue cells, positive whiff test, thin discharge and higher pH

Antibacterial therapy (nitromidazole-class or alternative)

Avoid vaginal douching; sexual health counseling

Genital Herpes (HSV-1/HSV-2)

Herpes simplex virus (enveloped dsDNA virus)

Ulcerative

Painful grouped vesicles → shallow ulcers, recurrent episodes

HSV-1 = oral-genital transmission

HSV-2 = classical cause of recurrent genital disease

Genital Herpes (HSV-1/HSV-2) Diagnosis, Treatment, and Prevention

PCR from lesion swab, serology if necessary

Antiviral therapy. Supportive care

Avoid sexual contact during outbreaks; consider suppressive therapy. Latency

Syphilis

Treponema pallidum (spirochete)

Ulcerative

Primary: Painless chancre

Secondary: Rash, condyloma lata, systemic symptoms

Tertiary/Latent: Neurologic/Cardiac disease. Gummas (skin)

Syphyilis Diagnosis, Treatment, and Prevention

Non-treponemal + treponemal tests

Antibacterial therapy (beta-lactam class)

Screening, safer sex, prenatal care

Chancroid

Haemophilus ducreyi (Gram negative coccobacillus)

Painful genital ulcers, irregular and purulent base; tender inguinal lymphadenopathy

Chancroid Diagnosis, Treatment, and Prevention

Clinical + exclusion of other ulcerative STIs

Antibacterial therapy (macrolide or beta-lactam classes)

Safer sex practices; rare in high-income countries

Lymphogranuloma Venereum (LGV)

Chlamydia trachomatis L1-L3 (obligate intracellular)

Small painless ulcer → painful inguinal lympahdenitis (“buboes”), protocolitis

Lymphogranuloma Venereum (LGV) Diagnosis, Treatment, and Prevention

NAAT with serovar identification

Antibacterial therapy (tetracycline-class)

Prevention in MSM communities; safer sex

Donovanosis

Klebsiella granulomatis (Gram negative)

Chronic beefy-red ulcers that bleed easily

Donovanosis Diagnosis, Treatment, and Prevention

Tissue smear with Donovan bodies

Antibacterial therapy (macrolide-class)

Safer sex, early diagnosis. Endemic tropical regions

Human Papillomavirus (HPV)

Non-enveloped circular dsDNA virus

Genital warts (types 6/11), cervical dysplasia (16/18). Can also affect anogenital and oropharyngeal mucosa

Human Papillomavirus (HPV) Diagnosis, Treatment, and Prevention

Pap smear, HPV DNA testing

Local treatments for warts; lesion removal. No antiviral cure

HPV vaccination; screening programs. Vaccine (children = before first sex)

HIV, HBV, HCV

HIV retrovirus; HBV enveloped DNA hepadnavirus; HCV RNA flavivirus

HIV: acute → syndrome → chronic aids

HBV/HCV: Chronic hepatitis risk

HIV, HBV, HCV Diagnosis, Treatment, and Prevention

Serology + PCR depending on virus

Antiretroviral therapy (HIV); antivirals for HBV/HCV. Supportive care

Condom use; vaccination (HBV); harm reduction)

Molluscum Contagiosum

Poxvirus (large dsDNA virus)

Umbilicated pearly paules on genital/perineal region. No pain, self-limited

Molluscum Contagiosum Diagnosis, Treatment, and Prevention

Clinical diagnosis

Supportive care; local removal if needed

Avoid direct skin contact; hygiene

Pubic Lice (Pediculosis pubis)

Ectoparasite: Pthrius pubis

Intense genital itching; visible lice/nits

Pubic Lice (Pediculosis pubis) Diagnosis, Treatment, and Prevention

Clinical inspection

Topical pediculicides

Avoid sharing bedding/clothing; partner treatment

Scabies

Mite: Sarcoptes sabiei

Burrows, papules, intense nocturnal itching

Scabies Diagnosis, Treatment, and Prevention

Clinical diagnosis; skin scraping

Topical or oral antiparasitic therapy

Treat household/sexual contacts; hygiene