Gram (+) Bacteria

Question 1

Streptococci

Answer 1

catalase (-)
non-motile
facultative or obligate anaerobles
Lancefield groupings (A,B,D)

Question 2

Group A Strep.

Answer 2

S. pyogenes. B-hemolysis, #1 cause of bacterial pharyngitis, impetige, rheumatic fever, post-strep glomerulonephritis, necrotizing fascitis, toxic shock syndrome

Question 3

Group B Strep

Answer 3

S. agalactiae, B-hemolysis, #1 cause of neonatal septicemia, meningitis, and pneumonia

Question 4

Group D Strep

Answer 4

S. bovis and S. equinus. G or A-hemolysis, endocarditis, urinary tract infections

Question 5

S. pneumoniae

Answer 5

A-hemolysis, #1 cause of bacterial pneumonia in adults, capsule, meningitis in adults, otitis media in children, optochin sensitive

Question 6

S. viridans

Answer 6

A-hemolysis, microaerophilic, dental caries, subacute endocarditis, aspiration pneumonias and abscesses

Question 7

Streptococcis virulence factors

Answer 7

M proteins (S. pyogenes) resists phagocytosis
Capsules (S. pneumoniae, S. pyogenes, S. agalactiae)
erythrogenic exotoxin (S. pyogenes) causes scarlet fever, toxic shock syndrome

Question 8

Enterococci

Answer 8

diplococci or short chains
catalase (-)
G-hemolytic
non-motile
facultative anaerobes
UTIs, bacteremia
VRE=vacomycin resistant enterococci
also very resistant to ampicillin

Question 9

Staphylococci

Answer 9

catalase (+)

Question 10

S. aureus

Answer 10

coagulase (+)

pneumonia, meningitis, acute endocarditis, osteomyelitis, TSS, food poisoning

Question 11

Staphylococcus virulence factors

Answer 11

clumping factor
polysaccharide capsule (resists phagocytosis)
surface A protein (inhibits Igs)
exfoliative A and B toxins (scalded skin syndrome)
superantigens (TSS1 and heat stable enterotoxin)

Question 12

Bacillus

Answer 12

aerobes to facultative anaerobes

spore-formers

Question 13

B. cereus

Answer 13

preformed enterotoxins > food poisoning

Question 14

B. anthracis

Answer 14

polyglutamyl capsule (survives phagocytosis)
exotoxins
cutaneous anthrax (95%)
GI anthrax (contaminated meat > bloody diarrhea)
inhalation antrax (woolsorter's disease, pneumonia, hemorrhagic mediastinitis)

Question 15

Clostridia

Answer 15

G+ rod
spore former
obiglate anaerobes

Question 16

C. tetani

Answer 16

racket-shaped

single exotoxin > tetenus, blocks inhibitor of neurotransmission

Question 17

C. perfringens

Answer 17

anaerobic mixed wound infections
exotoxins
gas gangrene

Question 18

C. botulinum

Answer 18

botulinum exotoxin > block ACh release
Type A is most potent exotoxin known
poorly canned foods
flaccid paralysis, diplopia, dysarthria, dysphonia, dysphagia, respiratory failure
infant botulism: bee honey
wound botulism

Question 19

C. difficile

Answer 19

toxin A (enterotoxin)
toxin B (cytopathic agent)
pseudomembranous enterocolitis
Rx: oral vanco, metronidazole, bacterial recolonization

Question 20

Corynebacteria

Answer 20

G+ rod-like, club-shaped

mycolic acid in cell wall

Question 21

C. diptheriae

Answer 21

diptheria toxin (cytotoxin)
pseudomembranous material in upper respiratory tract
Rx: vaccinate, passive immunization with antitoxin

Question 22

Listeria

Answer 22

G+ bacillus
facultative intracellular parasite
lysteryolysin O (can survive inside phagolysosome)
spread from cell to cell w/o extracellular stage

Question 23

L. monocytogenes

Answer 23

food-borne illness
hot dogs, lunch meat, milk, cheese, raw vegetables
miscarriage/stillbirth

Question 24

Gardnerella vaginalis

Answer 24

Gram-variable, cell wall is G+

bacterial vaginosis, clue cells, fishy odors

Question 25

Gram (+) anaerobic cocci

Answer 25

anaerobic
G+
non-spore forming

Question 26

Peptostreptococcus magnus

Answer 26

skin and soft tissue infections

Question 27

Peptostreptococcus anaerobius

Answer 27

oral infections