Bacteriology-48 Bacterial Vaginosis, Trichomonas, and Vaginal Yeast Infections*
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- What is the prevalence of vaginitis
- One of the most common reasons for gynecologic consultation (10 million annually)
- What are the etiologies of vaginitis
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Bacterial vaginosis 40-50%
Candidiasis 20-25%
Trichomoniasis 15-20% - How does estrogen influence the vaginal flora
- It stimulates glycogen-rich epithelium
- What microbe predominates the vagina in childbearing years
- Mixed Lactobacillus species
- What are the characteristics of mixed Lactobacillus species
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Diverse group of obligate anaerobic, facultative and microaerophilc species
Produce acid that maintains low pH
Some produce H2O2
Lactobacilli attach to vaginal epithelium and can block adherence of pathogens - What is Bacterial vaginosis
- Imbalance of normal flora, involving interactions among many microbes
- Bacterial vaginosis is associated with what specific organism
- Gardnerella vaginalis
- What are the characteristics of Gardnerella vaginalis
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Pleomorphic, small gram negative or gram variable coccobacillus, facultative anaerobic
20-40% healthy asymptomatic women
Can be equally transmitted into urethra of male partner - What is the microbiology of bacterial vaginosis
- Overgrowth of several species of anaerobes from the normal flora, like Mobiluncus spp and Bacteroides spp. Causes inhibition of normal lactobacilli. Associated with Gardnerella vaginalis
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Thin, malodorous vaginal discharge
Vaginal pH elevated
Shedding of epithelial cells with adherent bacteria (clue cells)
Lack of inflammatory cells
Diagnosis? - Bacterial vaginosis
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These are predisposing factors for what?
Sexual activity
Onset of menses; pregnancy; menopause, oral contraceptives
Excessive douching (washing)
Bacteriophage that causes decrease in normal lactobacilli colonization levels
Antibi - Bacterial vaginosis
- What risks are associated with Bacterial vaginosis
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Adverse events in pregnancy, preterm labor, premature rupture of membranes, preterm birth, intra-amniotic infection, post-partum endometritis
Post-surgical infections
Pelvic inflammatory disease, salpingitis
Increased risk of acquistion of STDs - How is bacterial vaginosis diagnosed
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Direct observation of abnormally high pH, Wet slide mount for clue cells, gram stain for clue cells and small gram variable coccobacilli
Culture for Gardnerella vaginalis on human blood agar plates - How is bacterial vaginosis treated
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Topical metronidazole
Oral metronidazole - Proliferation of normal flora yeast will cause what
- Yeast (Candida) vaginitis. It is not sexually transmitted
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Profuse vaginal discharge, white, cheese or curd like
WBC/epithelial cell ratio in discharge variable
Vaginal pH and bacterial flora (including lactobacilli) normal
Diagnosis - Yeast vaginitis
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Onset of menses; pregnancy; menopause; oral contraceptives
Post-systemic antibiotic treatment in normal women
Diabetes Debilitated, immunocompromised
These conditions can trigger what - Overgrowth of vaginal yeast
- What risks are associated with yeast infections
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Minimal risks in non-immunocompromised
May require systemic therapy if recurrent or in immunocompromised - How is Yeast vaginitis diagnosed
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Direct observation of wet mount of vaginal scrapings for large budding yeast cells and or pseudohypae, alone or with 10% KOH, and Gram stain to visualize yeast
Culture on blood agar - How is yeast vaginitis treated
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Topical azole therapies
Oral fluconazole for persistent or recurrent episodes - What are the characteristics of Trichomonas vaginalis
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Flaggellated protozoan
Reproduction by binary fission; no sexual stages or cyst stage
Human vagina is reservoir; sexually transmitted
Aerotolerant anaerobe - What is the epidemiology of Trichomonas vaginalis
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Most prevalent non-viral STD in the world
More common in women than men
Higher incidence in the disadvantaged, debilitated, immunocompromised, and those at risk for other venereal diseases -
Many infections are asymptomatic
Thin, watery or purulent yellowish malodorous vaginal discharge
Itching, pain, inflammation (accompanied by neutrophil response)
Increased pH
Diagnosis - Infection with Trichomonas vaginalis. It is very similar to bacterial vaginosis, and 85% of patients with Trichomonas vaginalis infections also have bacterial vaginosis flora
- What risks come with Trichomonas vaginalis infections
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Postpartum endometritis
Premature labor; premature rupture of membranes; low birthweight
Inflammation and erosion of the epithelium
Increased susceptibility to other infections (HIV)
Infection of newborn at parturition - Why are repeated and persistent infections with Trichomonas vaginalis common
- Strains undergo phase variation of surface glycoprotein (gp270) double-stranded RNA virus in parasites' cytoplasm.
- Is Trichomonas vaginalis infection more severe in the immunocompromised
- No, but it is more prevalent
- How is Trichomonas vaginalis diagnosed microscopically
- Observe motile organisms in secretions suspended in drop of saline
- If Trichomonas vaginalis is diagnosed, what else should be examined
- The possibility of other STDs
- What is the treatment for Trichomonas vaginalis
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Metronidazole. This is also the treatment for bacterial vaginosis. Treatment during pregnancy should be oral only.
Clindamycin is an alternate drug