STD Bugs Flashcards
Candida albicans
Yeast cells w/ pseudohyphae on wet prep/gram stain.
MCC of vaginosis.
Normal biota –> DM, HIV, Pregnancy, Recent Abx
Presents w/ ithciness, yellowish discharge in large amounts (cottage cheese like)
Normal vaginal pH on KOH amine test (above 4.5)
Rx: Azole (if recurrent consider partner)
Trichomonas vaginalis
Common cause of vaginosis.
Presents w/ itchiness, yellowish discharge in large amounts
Elevated vaginal pH on KOH amine test (above 4.5)
Dx: Protozoa on wet prep.
Causes asymptomatic infections; vagintis; premature labor and low birth weight if pregnant. Chronic infection can cause infertility.
Rx: Metronidazole
Gardernella vaginalis
Common cause of vaginosis.
Presents w/ discharge typically white/gray in moderate amount. Very malodorous.
Elevated vaginal pH on KOH amine test (above 4.5)
Clue cell (vaginal cell covered in bacteria) on wet prep
Rx: Metronidazole
HPV
Human Papillomavirus
- dsDNA goup 1
- Circular genome
- Icosahedral
- Noneveloped
- Papovaridae
- Papillomavirus
Viral needs to use host DNA pol –> needs to be in active cells and thus must penetrate outer skin
Transmission: Direct sexual contact
Virulence factors:E1 - helicase at site of replication; E2 loads E1 on viral genome; E6 binds E6AP, a ubiquitin enzyme which destroys p53 and E7 binds rb that doesn’t allow rb to bind E2F allowing uncontrolled growth and eventually cancer.
Dx: PCR/Clinical
Prevent infx w/ vaccine and prevent cancer with pap smear
Rx: Can remove warts or cancer; virus not curable
May cause laryngeal warts on fetus
Common cause of cervical, anal, and oral cancer.
Self-resolve in most.
HSV-2
- DS DNA, group 1
- Linear Genome
- Icosahedral
- Enveloped
- Alpha Herpes Virus (neuron latency –> sacral ganglia)
Genital herpes (some cross over w/ HSV-1)
Transmission: Direct contact, vertical
Dx:Tzanck smears w/ multinucleated cells. Clinical presentation; PCR; viral culture
Prevention: Avoid contact. Antivirals reduce transmission.
Rx: Acyclovir (only shortens outbreaks; doesn’t kill latent cells –> no thymidine kinase)
Asymptomatic to frequent painful vesicular recurrences.
Can cause encephalitis. Do get initial viremia (combatted by CD8’s). Can also cause herpetic whitlow on finger w/ broken skin.
Blindess or disseminated herpes in neonate
Treponema pallidum
Gram - spirochete w/ complex growth requirements (intracellular organism)
Causes syphillis
Trasmission: Direct contact and vertical
Virulence factors: Lipoproteins
Dx: Immunoflorescence, dark field microscopy. Blood tests (VRDL; FT-abs). RPR (anti-cardiolipin antibody), PCR
Prevention: Penicillin G to all possible contacts. Avoid sexual contact.
Rx: Penicillin G
Primary: Painless hard chancer (9days to 3 months post infection). Enlarged lymph nodes w/o systemic sx.
Secondary: (3weeks to 6 months) Fever, headache, sore throat, lymphadenopathy, red or brown rash on all skin surfaces including rash on palms and soles. Lesions contain spirochete bacteria.
Tertiary: (years) antibodies are detectable, but tough to find spirochete. Tabes dorsalis; prostitute’s pupil; Aortitis; Heart failure; Gummas in tissues (liver, skin, bone, cartilage); Cranial nerve involvement.
Congenital syphilis: MC in 2nd and 3rd trimester. Inhibits fetal growth; miscarriage/stillbirth; skin eruptions; notched teeth, saber tibias, bone deformities
Not infectious during latent and tertiary stages
Jarish-Herxheimer reaction: Fever, rash, etc. with treatment –> release of spirochetes.
Neisseria gonorrhoeae
Typically purulent discharge in men (only bug)
Gram negative intracellular diplococci
Oxidase +
Only glucose oxidizer (vs. meningitidis)
A lot of antigenic variation
Virulence: Endotoxin, Capsule, pili, and IgA protease
Grows on Thayer-Martin media
Rx: Ceftriaxone (+azithromycin for Chlymidia). Erythromycin eye drops in neonates.
Obligate human pathogen.
Local infection (Genital/anorectal): Asx, urethritis, dysuria (men); cervicitis, opthamlia neonatorum
Systemic infection: Septic arthritis
Complications if untreated: PID, ectopic, Fitz-Hugh-Curtis syndrome (adhesion to liver)
Higher incidence w/ menstration or IUD
Chlamydia trachomatis
Obligate intracellular Gram negative
coccobacilli.
non motile
non-spore forming
Life cycle: Reticular bodies for intracellular; Form elementary bodies which are infectious form
Disease manifestations vary by serovar. Causes trachoma (A-C), urethritis (D-K), PID, neonatal pneumonia, neonatal conjunctivitis, and lymphogranuloma venereum (L1-L3)
Lymphogranuloma venereum = painless ulcer w/ local lymphadenopathy (buboes). Multiple draining sinuses that can cause proctatitis and renal stricture
Can cause FHC syndrome as well as Reiter’s.
Rx: Azithromycin, or tetracyclines (+ceftriaxone for neisseria coinfection)
Molluscum contagiosum
Poxvirus
STD also indirect and autoinnoculation
Clinical dx
Prevention: Avoid direct contact
Rx: Remove warts; virus not curable
Haemophilus ducreyi
Causes chancroid = painful ulcers (you do cry)
Klebsiella granulomatosis
Generally painless genital ulcer, rare in US
