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75 Cards in this Set
- Front
- Back
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What kind of organism causes syphilis?
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Thin spirochete
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What does T. pallidum do to avoid host immunity?
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Has few exposed proteins to act as antigens
Coats itself with host fibronectin (like molecular mimicry) |
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What are the most important virulence molecules for syphilis?
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Adhesins
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Why is syphilis still able to be treated by PCN when many bacteria are not?
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It is very stable - lacks transposons and divides slowly so has not developed resistance
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Which immune response is best at clearing T. pallidum infection?
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TH1
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What are some of the most concerning complications caused by T. pallidum?
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Obliterative endoarteritis
Glomerulonephritis due to immune complex formation |
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Patient presents with skin lesions and obliterative endoarteritis. What STD do they likely have?
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Syphilis (T. pallidum infection)
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When are syphilis patients most infective?
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Early in disease, esp when lesion present (secondary syphilis)
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When does congenital syphilis present?
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Around 4mo into pregnancy since many of the symptoms are due to immune response and that is when fetus' immune system has started to really develop
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What is a characteristic of the syphilis lesion that helps distinguish it?
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Painless
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Patient presents with a painless chancre on their penis with swollen inguinal lymph nodes. What do they probably have and what stage?
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Primary syphilis
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What are condylomata lata and what disease are they associated with?
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Moist, heaped, wart-like lesions in intertriginous areas that are very infectious.
Syphilis |
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What is an area of the body where secondary syphilis lesions can be found that is somewhat unique?
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Palms and soles
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What part of the CV system is commonly involved in tertiary syphilis due to endarteritis obliterans?
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Aorta
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What is the consequence of Group I congenital syphilis?
What proportion get this? |
No live birth
2/3 |
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What is the consequence of Group II congenital syphilis?
What proportion fit into this group? |
Baby is born with syphilis and has symptoms/signs such as snuffles, a dequamative rash, osteochondritis commonly involving the palate
1/3 |
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What test is used to diagnose primary syphilis?
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Darkfield demonstration of treponemes
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What are the two categories of serological tests for syphilis and what is an example of each?
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NTS (RPR)
Treponemal AB test (FTA) |
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When is NTS serological testing for syphilis done? (3)
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In most cases, it is done first because it is cheap and easy (if positive, do a treponemal test to confirm since NTA test is not very specific)
-Done to evaluate success of therapy since titers should plummet after therapy is started if it is working -Do this in CSF to test for neurosyphilis if serum test is positive |
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What is the treatment for syphliis?
What is used for PCN-sensitive people (and what is the exception to this?) What is a common reaction? |
PCN
Tetracycline/doxycycline (if pregnant, go with PCN but desensitize in hospital first) Jarish-Herxheim reaction common |
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What organism causes chancroid?
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Haemophilus ducreyi
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What type of organism is H. ducreyi?
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Fastiduous extracellular GNB
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What are two virulence mechanisms of chancroid?
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Evades phagocytosis, produces a toxin that leads to necrosis
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What is the effect of chancroid on pregnancy?
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None
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What are the lesions like in chancroid?
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Painless papules that ulcerate
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What sxs besides the lesions are seen with chancroid?
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Lympadenopathy
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What are two diseases that are important to rule out when diagnosing chancroid?
How are these distinguished? |
Syphilis - can do darkfield. also, lesions are painless with syphilis and painful with chancroid
Herpes - more systemic sxs seen with herpes that are not present with chancroid or do ulcer exudative test (+ with herpes, - with chancroid) |
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What is the treatment for chancroid?
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Azithromycin
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What type of organism causes molluscum contagiosum?
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Poxvirus (enveloped DNA)
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Where does molluscum contagiosum replicate?
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Lower layers of epidermis
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Where are the inclusions of molluscum contagiosum seen?
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Prickly cell layer
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What do about 15% of AIDS patients have opportunistic infections with?
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Molluscum contagiosum
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What is the treatment for molluscum contagiosum?
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Don't bother, they will go away.
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What type of organism causes HPV?
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Papillovirus (naked DNA)
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What parts of the genome of HPV are involved in transformation of infected cells?
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E5-7
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What are 3 characteristics of the pathogenesis of HPV?
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Noncytolitic
No viremia Long infectious cycle |
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What kinds of cells are diagnostic of HPV?
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Koilocytes
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What happens in dysplasia?
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DNA of virus is integrated into host chromosomes, leading to disruption of E1 and E2 which are normally involved in downregulation of E6 and E7.
With E6 activation, p53 is degraded With E7 activation, retinoblastoma is bound --> this leads to impeded apoptosis and increased mitosis which means there is a higher chance of mutation and cancer (happens over a few years though) |
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What type of immunity is important in controlling HPV?
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CMI
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What age group most commonly gets common cutaneous warts?
Plantar? Juvenile flat? |
School-age children get common warts
Adolescents or young adults get plantar warts. Children get juvenile flat warts but this is the least common |
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What percentage of people with anogenital HPV warts are asymptomatic?
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75%
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What type of vaccine is Gardasil?
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uses capsid VLPs
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What type of an organism causes GC?
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Aerobic, gram neg cocci (kissing kidney beans that may be in PMNs)
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What is the main contributor to pathogenesis of GC?
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Antigenic variation
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What do pili of GC do?
Por? Opa? Rmp? LOS? IgA protease? |
Pili are involved in attachment and interfering with PMN phagocytosis
Por help intracellular survival, invasion of epithelium and resistance to compliment Opa is involved in strengthening attachment and organism internalization Rmp protects other surface proteins from antibodies LOS is an endotoxin IgA protease destroys IgA |
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What is the outcome of GC infection for most people?
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Sloughing of epithelium, exudation of pus and spontaneous resolution
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What group of people have the highest rates of GC infection?
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Sexually active 15-19yo females
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What clinical symptoms are seen in men with GC?
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Most men are symptomatic and get urethritis with lots of pus and dysuria that lasts 2-5 days and spontaneously resolves.
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What clinical symptoms are seen in women with GC?
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Endocervical infection, although usually asymptomatic. 8-10 days of discharge seen with dysuria that ascends in 45% of women into salpingitis and PID
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What does GC acquired during pregnancy cause?
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Spontaneous abortion, premature membrane rupture, or increased mortality for the infant
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What are the symptoms of PID? How often is it caused by GC (with or without other coinfections)?
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low abdominal pain
fever elevated WBC may have complications such as infertility, ectopic pregnancy, RUQ pain due to perihepatitis |
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What type of media is used to culture GC?
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Thayer Martin (chocolate + antibiotics, CO2 needed for growth too)
OXIDASE POSITIVE |
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What test can be used in GC suspected in men but not women?
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Gram stain
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What is the treatment for GC?
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3rd generation cephalosporins
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What are common target cells for the trachoma serovars of Chlamydia?
Of the LGV serovars? |
Squamocolumnar epithelial cells of endocervix and upper genital tract in women
Conjunctiva, urethra, and rectum in both men and women Columnar epithelial cells in resp tract of infants Same in LGV but also macrophages |
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What do mycoplasma species involved in genital disease look like?
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Tiny, slow-growing, extracellular, lack cells walls
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How do mycoplasma or ureaplasma accomplish pathogenesis?
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Directly damages epithelium or recruits inflammatory cells
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Woman presents with postpartum fever. What are three likely culprits?
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M. hominis, M. genitalium, Ureaplasma urealyticum
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What is the recommended treatment for urethritis involving mycoplasma or ureaplasma?
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Azithromycin or doxycycline (same as chlamydia so since often present with other infections and not able to be diagnosed with lab tests, taken care of with other infection)
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What is the predominant bacteria in the normal vagina?
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H2O2-producing Lactobacilli (gram-positive, non-motile)
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What is the normal vaginal pH?
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Under 4.5
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What are the three most common agents in vaginitis or vaginosis?
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Candida albicans
Trichomonas vaginalis Bacterial vaginosis |
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What is more likely to have asymptomatic trichomonas infection, men or women?
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Men (trichomonas vaginitis)
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What does the trichomonas vaginitis parasite look like?
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Flagellated protozoan
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What immune response is triggered by trichomonas?
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Alternate complement pathway
Attracts PMNs |
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Young sexually-active woman presents with 2 day history of vaginitis characterized by purulent discharge (and increased discharge), dyspareunia, dysuria, and abonormal odor. What is the likely culprit?
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Trichomonas vaginitis
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Which vaginitis agents increase susceptibility to HIV infection and may lead to LBW babies if gotten in pregnancy?
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Trichomonas vaginitis
BV |
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What is the treatment for trichomonas? Should partners be treated?
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Metronidazole
Yes |
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What is the major vaginal pathogen of immunocompromised hosts?
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Candida albicans
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What is the cause of the symptoms of candida infection?
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Noninflammatory
Sxs due to adherence and penetration of hyphae into vaginal epithelium |
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What is the treatment for candida infection? Should partners be treated?
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Topical miconazole, butoconazole, clotirmazole
Oral fluconazole No |
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What cells are found in culture of women with BV?
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Clue cells (anaerobic bacilli)
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What is the treatment for BV? Should partners be treated?
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Metronidazole
No |
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Infection with what leads to a pruritic, eczematous skin eruption?
What is the treatment? |
Scabies
Permethrin (topical) or Ivermectin (oral) |
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Infection with what leads to itching and can be visualized by lice hanging onto hair shafts?
What is the treatment? |
Phthirus pubis
Crab lice Permethrin or Pyrethrins (topical) |
