Microbio 5 Flashcards
Arboviruses (arthropod-borne viruses)
[viruses and associated diseases]
> Flaviviruses: Yellow fever, Dengue, St. Louis encephalitis, West nile virus.
Togaviruses: Eastern/Western equine encephalitis.
Bunyaviruses: California encephalitis, Sandfly/Rift Valley fevers, Crimean-Congo hemorrhagic fever.
MC pathogens of nosocomial bloodstream infections
Coag (-) staphylococci
S. aureus
Enterococci
Candidae
What is Waterhouse-Friderichsen syndrome a complication of?
Complication of meningococcemia by N. meningitidis.
>Primary adrenal insufficiency (due to adrenal hemorrhage and destruction), associated w/ sepsis, DIC, shock
How would an Aspergilloma appear on CXR?
A radiopaque structure in an old cavitary lesion that shifts when patient changes position.
*Not contagious; no invasion of lung tissue, just colonization
What virulent factor is most important in E. coli that allows for meningitis (neonatal)? UTI?
> K1 capsular antigens are determinants of virulence for meningitis.
P fimbriae (pili) is a major virulence factor for UTI.
Why is it that some patients (esp. elderly) who recover from an Influenza infection may later develop ssx of pneumonia?
This is a small subset of patients who develop secondary bacterial pneumonia after an Influenza infection. The mucociliary clearance mechs were damaged by the previous viral infection, allowing for certain bacterial pathogens to infect (S. pneumoniae, S. aureus, H. influenza).
Ether is able to inactivate: enveloped virus or nonenveloped virus?
Enveloped viruses are inactivated by ether – outer lipid bilayer acquired from host membrane.
>Loss of infectivity
Acute bacterial parotitis
[MCC, dx, predisposition, ssx]
MCC: S. aureus
>More commonly in elderly post-op patients who are intubated or dehydrated
>Postauricular swelling extending to mandible
>Dx: inc. serum amylase (normal lipase, no pancreatitis)
>CT: ductal inflammation/obstruction, abscess
Lipooligosaccharide of N. meningitidis.
What do high levels indicate?
Similar to LPS endotoxin.
High levels assctd w/ septic shock and death.
>Meningococcal growth and lysis releases outer membrane vesicles w/ LOS attached – systemic inflammatory response – sepsis (as in Waterhouse-Friderichsen syndrome).
HSV-1 encephalitis
[Causes, presentation]
1) Primary oropharyngeal infection – olfactory tract – brain
2) Reactivation of dormant virus in trigeminal ganglion – spreads to brain
*Hemorrhagic necrosis of temporal lobe – aphasia, personality changes; classic features of encephalitis (seizures, altered mental status, headaches)
(Also called Temporal Lobe Encephalitis, MCC of sporadic encephalitis)
Genital ulcer diseases (syphilis, genital herpes, chancroid, granuloma inguinale, lymphogranuloma venereum)
[Description of ulcer]
> Syphilis: painless ulcer w/ heaped up borders and clean base.
Genital herpes: multiple, painful vesicles or ulcerations, erythematous base.
Chancroid: deep, purulent, painful ulcers w/ gray to yellow exudate.
Granuloma inguinale (donovanosis): painless, red serpiginous ulcerations w/o lymphadenopathy.
Lymphogranuloma venereum: small ulcers w/ painful inguinal lymphadenopathy.
DDx of vaginitis (Bacterial vaginosis, Trichomoniasis, Candida vaginitis)
[PE]
> Vaginosis: Off-white discharge w/ fishy odor, no inflammation.
Trichomoniasis: yellow-green, foul-smelling, frothy discharge; vaginal inflammation.
Candida vaginitis: thick, “cottage cheese” discharge; vaginal inflammation.
