chap 21-26

Question 1

staphylococcus species

Answer 1

• gram pos cocci; opportunistic pathogen

Question 2

S. aureus virulence factors

Answer 2

• toxin anti-phagocyte
• resist opsonization
• neutralize amps of host
• lysozyme resistant
• antibiotic resistant (mrsa, vrsa)

Question 3

staphylococcal skin infections

Answer 3

folliculitis - infection of hair follicles
sty - folliculitis of eyelash
furuncle(boil) - abscess; puss surround inflamed tissue
carbuncle - inflammation of tissue under skin
impetigo - crusting (nonbullous) sores, spread by autoinoculation

Question 4

streptococcus species

Answer 4

• gram pos; cocci chain
• a hemolysis = s. pneumoniaen s. mutans
  b hemolysis = s. pyogenes
  g hemolysis = enterococcus spp(not harmful)

Question 5

streptococcus pyogenes

Answer 5

• strep throat
  rheumatic fever - secondary immune response
  (sequelae)(scarlet fever)
  - make abs to m protein; then cross react w heart
  muscle protein
  erysipelas - infect dermal layer; toxin cause tissue
  destruction; lead to sepsis
  necrotizing fasciitis - “flesh eating disease”; toxin cause
  death of deep tissue; can affect muscles

Question 6

streptococcus pyogenes virulence factors

Answer 6

• M protein: prevent complement activate; facilitate
  adherence
• hyaluronic acid capsule: non antigenic
• prod streptokinase, hyaluronidase, streptolysin, exotoxin A(superantigen)

Question 7

bacterial meningitis

Answer 7

infection of meninges; cross the blood-brain barrier
- symp = fever, headache, stiff neck, nausea and
vomiting, then convulsion and coma
- diagnosis by gram stain and agglutination test of csf

viral meningitis - more common; serious; rarely fatal

Question 8

Neisseria meningitidis

Answer 8

• gram neg, aerobic, diplococci w capsule
  virulence factor = opa protein(entry), endotoxin,
  capsule, pili, phase variation
• 40% healthy nasopharyngeal carriers

meningococcal meningitis
- symp = throat infection, rash to bacteremia, then
cross blood brain barrier to csf
- death = few hrs after fever; need antibiotic therapy
- vaccination required for college students

Question 9

clostridium species

Answer 9

• gram pos; endospore forming
• tetnus and botulism toxin

Question 10

clostridium botulism

Answer 10

botulism toxin
- grow in canned food, release toxin; spore survive unless autoclaved
- toxin block acetylcholine for neural transmission
(flaccid paralysis)

Question 11

clostridium tetani

Answer 11

tetanus toxin
- anaerobe
- grow in punctured wound
- interrupts blood flow = tissue anaerobic
- block GABA release(inhibitory trans) = cause nerve spasms; spastic paralysis vis excessive nerve signal

Question 12

listeria monocyogenes

Answer 12

• gram pos, baccillus
  listeriosis(food illness)
• ingest contaminated food(dairy, process meat,
  smoked seafood, raw vegetables)
• flu like symptoms and gi symp; usually asymptomatic
  or milk
• serious = septicemia vis meningitis or
  meningoencephalitis; >25% mortality
• most in pregnant woman, infant, elderly, immunocom

pregnant woman - cross placenta; to kill infant
prevention = effective sanitation of food, and
refrigerate <4*c

Question 13

listeria monocytogenes virulence factors

Answer 13

• adherence - d galactose in surface
• produce invasins - allow pene of host, induce
  phagocytosis (for epithelial cell of GI)
• polymerization of host actin, make actin rocket
• produce hemolysins, phospholipase c, protease
• grow low temp

Question 14

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