Bugs And Drugs Flashcards
These bacterial toxins are encoded by a lysogenic phage:
Group A strep erythrogenic toxin (think scarlet fever), Botulinum toxin, Cholera toxin, Diphtheria toxin, Shiga toxin
Morphology of Moraxella catarrhalis
GN cocci
Respiratory GNRs
Bordetella pertussis; Burkholderia; Haemophilus (HiB or NTHi); Legionella (Legionella doesn’t gram stain super well but can be visualized with silver stain)
Why don’t Treponema pallidum and Leptospira gram stain well?
They are too thin to be visualized
Morphology of common bacterial causes of diarrhea
Campylobacter, Shigella, Salmonella, E.coli… These are GNRs
Morphology of a bacterial species associated with food poisoning from cantaloupe and cottage cheese
Listeria - GPR
These antibiotics are generally ineffective against anaerobes because they require O2 to enter into the bacterial cell walls:
Aminoglycosides: gentamicin, tobramycin
GP rods with spores
Clostridium
Asplenics are at particular risk of infection from these pathogens:
Encapsulated bacteria: the capsules serve as an anti phagocytes virulence factor. Asplenics have decreased ability to opsonize bacteria, leading to a decreased ability to clear these infections. Major ones are S.pneumoniae, HiB, N.meningitidis (these three are ones for which we have vaccines), Klebsiella pneumoniae, Salmonella, E.coli, Group B strep, Pseudomonas.
Pathogen that causes watery diarrhea in developing countries and pathogen associated with shellfish and shark bites: morphology
Vibrio species (V.cholera; V.vulnificans): comma-shaped GNRs
This bacteria produces biofilms and is implicated in otitis media quite frequently.
NTHi
Morphology of Neisseria (N.meningitides, N.gonorrheae)
GN cocci
Define transformation.
Ability of bacteria to take up free DNA (often generated by cell lysis). S.pneumo, HiB, and Neisseria can do this.
These bacteria don’t have cell walls, so they don’t gram stain
Mycoplasma, Ureaplasma
Mechanism for vaccines against encapsulated bacteria
Polysaccharide capsule conjugated to carrier protein, which enhances immunogenicity by promoting T cell activation, leading to class-switching on B cells. Examples are the PCV (pneumococcal conjugate vaccine), HiB vaccine, and meningococcal vaccine.
Why don’t these bugs gram stain well? Legionella, Rickettsia, Chlamydia, Bartonella, Ehrlichia, Anaplasma
Primarily intracellular
These bacterial toxins cause toxic shock syndrome.
Super antigens from Staph aureus (Toxic shock syndrome toxin - TSST-1) and Strep pyogenes (Exotoxin A). They bind to MHC class II molecules and to TCRs outside of the usual binding site, causing overwhelming release of pro-inflammatory cytokines.
Important aerobic bacteria
Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis
This bacteria produces biofilms and is frequently implicated in infective endocarditis following dental procedures.
Viridans strep (strep mutans)
This bacteria produces a blue-green pigment.
Pseudomonas aeruginosa
This bacteria produces biofilms and is frequently implicated in catheter and prosthetic device infection.
Staph epidermidis
Define specialized transduction.
Lysogenic phage infects a bacterium and incorporates its DNA into the bacterial chromosome. When the viral DNA is excised, parts of the surrounding bacterial DNA are taken with it as well, and those can be transferred to another bacterium.
Catalase-negative and/or SOD-negative anaerobes, which are generally foul-smelling due to short-chain fatty acid production
Clostridium, Bacteroides, Fusobacterium, Actinomyces
Obligate intracellular bacteria
Rickettsia, Chlamydia, Coxiella