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33 Cards in this Set
- Front
- Back
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Examples of bacterial STI
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Syphilis, gonorrhea, Chlamydia trachomatis (LGV), chancroid, agents of NGU, shigellosis, salmonellosis, campylobacteriosis, MRSA, etc.
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Examples of fungal STI
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Candida species, blastomycosis, etc.
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Examples of viral STI
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Hepatitis (A,B,C,E), HSV, HIV, CMV, HPV, Kaposi’s sarcoma (HHV-8), Marburg and Ebola,
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Examples of parasitic STI?
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Scabies, lice, giardiasis, etc.
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Examples of protozoal STI
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Trichomoniasis, cyptosporidiosis, etc.
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Chlamydia
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Most common bacterial STD in the US
Genus: Chlamydophilia Species: psittaci, pneumoniae, trachomatis |
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STI and HIV
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STIs increase the risk of HIV acquisition -3-5 fold
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Human Diseases caused by Chlamydophilia trachomatis
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Serotypes A, B, Ba, C
Hyperendemic blinding trachoma Serotypes D – K Inclusion conjunctivitis, nongonococcal urethritis, cervicitis, salpingitis, proctitis, epididymitis, pneumonia of the newborn Serotypes L1, L2, and L3 Lymphogranuloma venereum |
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Serotypes A, B, Ba, C of chlyamida
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Hyperendemic blinding trachoma
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Serotypes D – K of Chlyamydia
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Serotypes D – K
Inclusion conjunctivitis, nongonococcal urethritis, cervicitis, salpingitis, proctitis, epididymitis, pneumonia of the newborn |
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Transmission of Chlymadia
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Transmission is sexual or vertical
Highly transmissible (infection rates in partners >50%) Incubation period 7-21 days Significant asymptomatic reservoir 60-80% asymptomatic Re-infection is common Perinatal transmission: neonatal conjunctivitis in 30%-50% of exposed babies Neonatal pneumonia in 3-16% of exposed babies Thought to be more efficient from men to women |
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Risk Factors for Chlamydia
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Young age
Risky behaviors Cervical ectopy (columnar epithelial cells on ectocervix) New or Multiple sex partners Oral contraceptive use (cervical ectopy) Inconsistent use of barrier contraceptives H/o STD Presence of another STD |
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Chlamydia: microbiology
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Obligate intracellular bacteria
Needs host ATP Gram-negative-like cell wall Not visible on gram stain Target: squamocolumnar epithelium cervix, upper genital tract, conjunctiva, urethra, rectum Disease from host T cell-mediated response and inflammation, can be chronic Immunity: re-infection common with little protection from antibody response |
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What are Elementary bodies?
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small infectious particles found in secretions
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What are reticulate bodies?
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the EB transforms into a reticulate body (RB), which begins to multiply within an isolated area called an inclusion
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Life Cycle of Chlymidia
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1. Elementary body (EB): small, infectious particle found in secretions
2. The EB attaches to and enters a cell to replicate Strong immune response results increased damage and scarring at site 3. Within 8 hours, the EB transforms into a reticulate body (RB), which begins to multiply within an isolated area called an inclusion 4. Within 24 hours, some RBs change back to EBs. Eventually the cell wall bursts and the RBs are released into adjacent cells or transmitted to infect another partner/site |
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C. trachomatis Complications
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Pelvic Inflammatory Disease (PID)
Salpingitis Endometritis Perihepatitis (Fitz-Hugh-Curtis Syndrome) (Women) Conjunctivitis Proctitis (anal pruritis, discharge) Epididymitis Most common cause in young men Reiter’s Syndrome (reactive arthritis) occurs in 1% of symptomatic infections |
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Pelvic Inflammatory Disease (PID)
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Most often due to chlamydia & gonorrhea (often polymicrobial: strep, gm negatives, anaerobes, etc.)
Incidence decreasing due to screening |
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PID clinical manifestions
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low abdominal pain
adnexal tenderness cervical motion tenderness fever leukocytosis |
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Chlamydia diagnosis:
Testing Technologies |
Culture
Historically the “gold standard”, use in legal cases High specificity, Variable Sensitivity (50%-80%) Use in legal investigations Non-culture tests Nucleic Acid Amplification Tests (NAATs) Non-Amplification Tests (DFA, EIA, NA probe) Serology (use for LGV) |
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Chlamydia trachomatis:
Treatment |
Azithromycin 1 gm single dose
or Doxycycline 100 mg bid x 7d |
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Neisseria gonorrhoeae: epidemiology
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Less common than Chlamydia
Resurgence in 1990s in high risk groups: Multiple or new sex partners or inconsistent condom use Urban residence in areas with disease prevalence Adolescents, females particularly Lower socio-economic status Use of drugs Exchange of sex for drugs or money African Americans |
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GC Transmission
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Efficiently transmitted by:
Male to female via semen Female to male urethra Rectal intercourse Oral sex (pharyngeal infection) Perinatal transmission (mother to infant) |
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GC microbiology
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Gram-negative intracellular diplococcus
-Infects mucus-secreting epithelial cells -Evades host response through alteration of surface structures |
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GC Genital Infection in Men
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Urethritis:
Asymptomatic in 10% of cases Incubation period: usually 1-14 days for symptomatic disease, but may be longer Epididymitis |
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Gland disease in women with GC
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Accessory gland infection
Bartholin’s glands Skene’s glands |
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GC Syndromes in Men and Women: Disseminated gonococcal infection (DGI)
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Systemic gonococcal infection
Occurs infrequently. Women > Men Associated with gonococcal strains that produce bacteremia without associated urogenital symptoms Clinical manifestations: skin lesions, arthralgias, tenosynovitis, arthritis, hepatitis |
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GC Diagnosis:
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Culture
Appropriate for multiple sites Susceptibility testing can be done Standard of Care for legal cases Non-culture tests Amplified tests (NAATs) PCR, TMA, SDA Non-amplified tests DNA probe Gram stain |
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GC and antibiotic resistance
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Resistance
Penicillin – plasmid beta-lactamase production; chromosomal resistance (1970s) Tetracycline – plasmid-mediated high-level resistance (1985) Fluoroquinolones – plasmid-mediated (2000s) Quinolone resistance is increasing (15-20% of isolates) ~ 3% of isolates show decreased susceptibility to azithromycin Sporadic cases of decreased susceptibility to ceftriaxone, cefixime, and spectinomycin have been reported |
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Trichomonas vaginalis
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Flagellated anaerobic protozoa
Almost always sexually transmitted T. vaginalis may persist for months to years in epithelial crypts and periglandular areas Female to Female transmission documented May be symptomatic or asymptomatic, douching may worsen vaginal discharge, Untreated trichomoniasis associated with pre-term rupture of membranes and pre-term delivery |
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Clinical Manifestations in Women in Trichomonas vaginalis
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STRAWBERRY CERVIX
May be asymptomatic in women Vaginitis Frothy gray or yellow-green vaginal discharge Pruritus Cervical petechiae ("strawberry cervix") - classic presentation, occurs in minority of cases May also infect Skene's glands and urethra, where the organisms may not be susceptible to topical therapy |
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Trichomonas Vaginalis Diagnosis
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Motile trichomonads seen on saline wet mount
Vaginal pH >4.5 often present Positive amine test Culture is the “gold standard” Pap smear has limited sensitivity and low specificity DNA probes Male diagnosis - Culture First void urine concentrated Urethral swab |
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Trichomonas Treatment
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Metronidazole 2 g orally in a single dose
Same regimen for pregnancy Alternative: Metronidazole 500 mg twice a day for 7 days |
