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44 Cards in this Set

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  • Back
Where is N. meningitidis normally found?
Normal flora of nasopharynx
What are the sx. of meningicoccemia?
*diseeminated infection
*petechial rash
*pupura
*DIC
*shock
What are the symptoms of meningitis caused by N. meningitidis?
*H/A
*stiff neck
*mental status changes
What is the treatment for meningitis caused by N. meningitidis?
*rapid tx. w/ceftriaxone, PCN, cefotaxime
*rifampin prophylaxis for close contacts
Is there a vaccine for N. meningitidis? What is a drawback?
A vaccine is available for adults only but it doesn't protect against the B serotype.
What are some bacterial characteristics and virulence factors of N. meningitidis?
*G- diplococci
*antiphagocytic capsule
*blebbing outer membrane
*pili and adhesins
*LPS
Which Neisseria organism can be part of the normal flora?
N. meningitidis can be found in the URT, but n. gonorrheae is never part of the normal flora.
Describe the surface structure of N. gonorrheae.
*G- diplococci
*hypervariable surface structure
*NO capsule
*expresses pili, adhesins, and invasins
What kinds of symptoms can uncomplicated N. gonorrheae cause in men? Women? Infants?
*M: urethritis, purulent discharge, epididymitis
*W: cervicitis w/exudate, salpingitis, PID
*I: conjunctivitis
What are the hallmarks of DGI with N. gonorrheae?
*septic arthritis
*septicemia
*skin lesions
Describe the pathogenesis of N. gonorrheae.
*attacks non-ciliated cells
*taken up by endocytosis
*forms microcolonies
*rarely penetrates past subepithelium
Infection with N. gonorrheae carries other risks - what are they?
*increased susceptibility to HIV and other STD
*increased transmissibility of HIV
Should N. gonorrheae be treated with PCN?
No b/c of resistance problems. Ceftriaxone is the preferred tx.
How is gonorrhea diagnosed?
Culture, gram stain, or rapid screening test.
What triggers a bout of bacterial vaginosis?
Any change in the normal flora of the vagina which results in supression of lactobacilli and growth of gardnerella, mycoplasma hominis, et al.
What is the primary symptom of bacterial vaginosis? What causes this?
Fishy smelling discharge. Bacteria secrete proteases that break proteins into polyamines.
How is bacterial vaginosis diagnosed?
*presence of clue cells
*vaginal p > 4.5
*discharge appearance and odor
Why is it important to treat BV? What is the preferred treatment?
*numerous OB/GYN sequelae if untreated
*metronidazole, probiotics
What is the most common agent of UTI? What determines the site of infection with this organism?
*uropathogenic E. coli
*type of adhesin expressed and receptors on tissue
What is a Type 1 pili?
*expressed by UPEC
*binds mannose-containing receptors
*assoc. w/cystitis
What is the P pili?
*expressed by UPEC
*binds digalactoside residues in kidney
*assoc. w/pyelonephritis
What does the S pili bind?
*sialic acid
What does the Dr adhesion bind?
*DAF
Give two reasons as to why women may be more susceptible to UTI than men.
1.Shorter urethra
2.Prostatic fluid is protective
How might choice of contraception influence susceptibility to UTI?
*use of diaphragms increases risk
*use of condoms decreases risk
What is cystitis? What are the symptoms? How is it treated?
*infection of the lower urinary tract
*burning, painful urination
*turbid urine that may have blood
*tx. w/short course of antibiotics
What is pyelonephritis? What are the symptoms? How is it treated?
*infection with kidney involvement
*may lead to systemic bacteremia
*fever, chills, pain at the costovertebral angle
*may cause renal scarring
*tx w/long course of antibiotics
How can T. pallidum be visualized?
*Gram staining does not work
*silver stain
*dark field microscopy
Describe the membrane structure of T. pallidum.
*similar to G-
*smooth outer membrane
*periplasmic flagella
What are three modes of transmission for T. pallidum?
*needles
*sex
*congenital
Describe the 5 stages of disease by T. pallidum. At which stages is the pt infectious?
1.incubation
2.Primary: painless chancre
3.Secondary: rash (on palms and soles), mucus patches
4.Latent phase
5.Tertiary: CV, neuro, gummatous
*infectious at stages 1,2,3
How is syphilis diagnosed?
*non-treponemal screening test
*highly specific treponemal confirmatory test
How is T. pallidum studied?
Animals must be used - no in vitro culture.
What are the 3 main serovars of Chlamydia trachomatis?
1.Ocular
2.Genital
3.Lymphogranuloma venereum (LGV)
What animal reservoir is Chlamydia psittaci associated with? How is it spread among humans?
*Birds - shed in feces
*there is no p-p spread
Describe 2 disease states associated with Chlamydia psittaci.
*respiratory infection with atypical pneumonia
*gestational psittacosis: premature labor, sponatneous abortion
Chlamydia pneumoniae caused what percentage of community acquired pneumonia?
10-20%
T/F:
Chlamydia is able to colonize the epithelial surface or invade and replicate within cells.
False: Chlamydia is an obligate intracellular pathogen, so it can only live inside of cells.
What are the two forms of the chlamydia organism? Which is infectious? Which is metabolicallly active?
*elementary body: highly infectious, metabolically inactive
*reticulate body: noninfectious, metabolically active
What is an "inclusion"?
An intracellular vesicle filled with reticulate and elementary bodies of Chlamydia. It is released by exocytosis or host cell lysis.
How is tissue damage mediated in a Chlamydia infection?
By chronic inflammatory response.
How is a chlamydia infection diagnosed?
Typically by urine screening test.
When considering treatment for chlamydia what ia essential?
*the rx must be able to penetrate the cell
*doxycycline and azithromycin are recommended
What are clue cells?
Exfoliated epithelia wiith large numbers of Gardnerella attached; diagnostic of bacterial vaginosis