Flashcards in Microbiology of your ulcerated (and cottage cheese) junk Deck (23)
What microbes cause ulcerative STIs?
Chlamydia trach. (LGV)
What causes chancroid?
How do you diagnose chancroid?
1. No evidence of T. pallidum infection by DFM of exudate or DFA-TP
2. Presentation of ulcers not typical for HSV or HSV culture negative
3. Confirm by culturing on Fildes-enriched gonococcal media (blood, AA, vitamins, serum) in a 10% CO2 atmosphere at 33-35C.
Name three pathogenic spirochetes
Borrelia (lyme disease)
Leptospira (zoonotic diseases)
Which spirochetes can be seen on light-field microscopy?
Borrelia is the only one large enough
Others must be visualized via dark field microscopy or with special stains
How do you diagnose T. palladium?
Can't be cultured
Darkfield microscopy or fluorescent antibody staining
Treponemal and non-treponemal serologic tests
What's the 50% infectious dose for syphilis?
easily infects mucus membranes
small cuts and abrasions make it easier
What are three methods by which syphilis can be spread?
What are the lesions of primary, secondary, and tertiary syphilis?
1-charcre 2-10 wks after infection, raised painless ulcer
2-condylomata lata, papulosquamous rashes of palms, soles, and genitals. Appear 2-10 wks after primary lesions vanish. extremely contagious
3-neurosyphilis, syphilitic aortitis. may occur years after infection
What are non-treponemal serologic tests?
VDRL, RPR, USR, TRUST
Based on Antibody lipid response
Sensitive for current infection but not specific
What are treponemal serologic tests?
Used for definitive diagnosis of syphilis
Other than contraception, what's the most common reason women seek GYN care?
What are three infective causes of vaginitis?
Bacterial vaginosis 40-50%
What is the cause of bacterial vaginosis and what predisposes women to this condition?
Loss of lactobacilli and overgrowth of Mobiluncus and Gardnerella (anaerobes)
Caused by changes in hormone status (estrogen favors lactobacilli), sexual activity, and antibiotic therapy/douching
What is normal vaginal pH and how do lactobacilli contribute?
Less than 5. Usually 4.5
Lactobacilli produce acid by fermentation
Diagnostic findings of BV:
Clue Cells (epithelium covered in gm+ rods)
Culture positive for Gardnerella vaginalis
Treatments for BV, Cadida, and Trichomonas? Which needs partner treatment?
Metroniadazole for BV and Trichomonas
Candida needs vaginal or systemic azoles
Trichomonas needs partner treatment to prevent recurrent infection.
What are the sx of a yeast infection?
What are risk factors for yeast overgrowth?
thick white curdy discharge
burning on urination
changes in hormone status
How do you diagnose yeast infection?
Microscopic Dx of budding yeast
Culture, PCR, and Probes work too
self diagnosis often confused with BV
What are the characteristics of Trichomonas vaginalis?
Replicates by binary fission
Human vagina is the reservoir
What are some similarities between T. vaginalis and BV?
What's the big difference?
Increased vaginal pH
Similar risks with infection
Inflammatory response is seen in Trichomoniasis
What are the risks of BV and T. vaginalis infection?
Increased risk of other STDs