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- Non-lactose fermenters on MacConkey agar
- salmonella, shigella, yersenia, campylobacter
- Do E coli ferment lactose?
- Yes
- Most common cause aseptic meningitis
- enterovirus
- How do + strand RNA viruses replicate?
- + strand RNA = mRNA, can be immediately translated. First translate proteins for the viral replicase, which is an RNA-dependent RNA polymerase to make + into -, then to +. + strands can be used to make proteins, amplify infection, or be template for more - strand
- How do enteroviruses infect the CNS?
- ingest fecal material -> virus infects mucosal + lymphoid cells in pharynx/intestine (1* viremia)-> start excreting in feces, seeds to extraneural cells -> either cross BBB in WBC, or via retrograde axonal transmission
- Salk created which vaccine?
- IPV (killed virus, get IgM/IgG, no reversion, but poor mucosal immunity)
- Herpes virus structure? Where do they replicate?
- Icosahedral capsid, surrounded by envelope, linear ds DNA. Replicate in nucleus
- How are herpes viruses spread?
- need close contact, like between mucosal surfaces, b/c they are fragile and don't survive well outside of body
- Three classes of herpes viruses and examples
- Classified by biologic/molecular methods. Alpha = HSV-1,2, VZV (grow rapidly, lyse infected cells, latent in sensory ganglia). Beta - CMV (slow growth, lysis slow, latent in WBC). Gamma - EBV (replicate in lymphoid, some lytic. Latent in B cells)
- Replication cycle for herpes
- glycoproteins on envelope tether to cell surface receptors -> fuse -> capsid/virus to cytoplasm -> to nucelus -> vmRNA made by host (IE,E,L). Capsid assembles in nucleus, get envelope from nucleus,
- Criteria for viral latency
- can detect viral DNA but no infectious viruses
- Genes expressed during latency
- no viral antigens or capsids, but some low-level transcription of other genes
- VZV pathogenesis
- spread by droplet nuclei or direct contact w/ lesions -> infect lymphoid tissue in pharynx -> viremia infects multiple organs and skin -> proceeds up local sesnory nerves to establish latency in ganglia
- Pathogenesis of herpes zoster
- latent VZV present, periodically reactivates, usually quelled by T cells. Immunity decr w/ age, so virus can travel back down nerve -> illness. This boosts immunity again so only get 1 case/lifetime
- Which streptococci are resistant to penicillins
- enterococci