Gram Positive Bacteria

Question 1

Prominent diseases caused by Staph aureus?

Answer 1

abscesses: impetigo, wound infections, endocarditis, septic arthritis, osteomyelitis, pneumonia
toxigenic: food poisoning, TSS, scalded skin syndrome

Question 2

Staph aureus virulence factors?

Answer 2

Coagulase, Protein A, capsule (some strains), cell wall has endotoxin properties, numerous enzymes and toxins cause skin damage, superantigens (heat resistant enterotoxin and TSST)

Question 3

Prominent diseases caused by Staph epidermidis?

Answer 3

pyogenic infection of in-dwelling catheters and prostheses; almost always hospital-acquired

Question 4

Staph epidermidis virulence factors?

Answer 4

Biofilm production

Question 5

Prominent diseases caused by Staph saprophyticus?

Answer 5

UTIs

Question 6

Prominent diseases caused by Strep pyogenes?

Answer 6

pharyngitis, cellulitis, impetigo, necrotizing fasciitis, scarlet fever, TSS, rheumatic fever, acute glomerulonephritis

Question 7

Strep pyogenes virulence factors?

Answer 7

M protein (serves as a pilus), inflammation-related enzymes (hyaluronidase, streptokinase, DNase), toxins & hemolysins (erythrogenic toxin, streptolysin O, streptolysin S, exotoxin A, exotoxin B)

Question 8

Prominent diseases caused by Strep agalactiae?

Answer 8

neonatal sepsis and meningitis

Question 9

Strep agalactiae virulence factors?

Answer 9

Polysaccharide capsule

Question 10

Prominent diseases caused by Strep pneumoniae?

Answer 10

lobar pneumonia, meningitis, otitis media

Question 11

Strep pneumoniae virulence factors?

Answer 11

Polysaccharide capsule

Question 12

Prominent diseases caused by Viridans streptococci?

Answer 12

pyogenic endocarditis following dental procedures, dental caries

Question 13

Viridans streptococci virulence factors?

Answer 13

Biofilm production in endocarditis

Question 14

Prominent diseases caused by Enterococci?

Answer 14

pyogenic UTIs and pyogenic endocarditis

Question 15

Bacillus anthracis virulence factors?

Answer 15

2 A-B exotoxins that share a common B subunit: edema factor (an adenylate cyclase that spurs fluid secretion) and lethal factor (a protease that inhibits cell growth)

Question 16

Prominent diseases caused by Bacillus cereus?

Answer 16

food poisoning as a result of spore germination upon heating contaminated food (esp rice)

Question 17

Bacillus cereus virulence factors?

Answer 17

Two exotoxins

Question 18

Prominent diseases caused by Clostridium perfringens?

Answer 18

gas gangrene and food poisoning

Question 19

Clostridium perfringens virulence factors?

Answer 19

Alpha toxin (exotoxin) that damages cell membranes

Question 20

Prominent diseases caused by Clostridium difficile?

Answer 20

Antibiotic-associated pseudomembranous colitis (most common cause of nosocomial diarrhea)

Question 21

Clostridium difficile virulence factors?

Answer 21

Exotoxin A and B which lead to depolymerization of actin and cell death

Question 22

Prominent diseases caused by Clostridium tetani?

Answer 22

tetanus/spastic paralysis caused by soil spores entering a wound

Question 23

Virulence factors of Clostridium tetani?

Answer 23

Tetanus toxin is an A-B exotoxin that cleaves Snares and prevents release of GABA

Question 24

Prominent diseases caused by Clostridium botulinum?

Answer 24

flaccid paralysis caused by consumption of botulism toxin

Question 25

Prominent diseases caused by Corynebacterium diphtheria?

Answer 25

diphtheria (severe pharyngitis)

Question 26

Prominent diseases caused by Listeria monocytogenes?

Answer 26

watery diarrhea caused by consumption of unpasteurized cheese or deli meats; sepsis or meningitis in newborns from infected mother

Question 27

What are the 2 most medically important genera?

Answer 27

Staphylococci (grape-like clusters) and Streptococci (chains)

Question 28

Are staph and strep catalase negative or catalase positive?

Answer 28

``` Staph= catalase + Strep= catalase - ```

Question 29

What is the most clinically important Staph species?

Answer 29

Staph aureus

Question 30

What are the normal flora of the colon?

Answer 30

enterococci

Question 31

What is the source of vancomycin resistance for multiple bacteria?

Answer 31

enterococci

Question 32

How are bacillus and clostridium categorized?

Answer 32

spore-forming gram + rods

Question 33

How are corynebacterium diphtheria and Listeria monocytogenes categorized?

Answer 33

non-spore-forming gram + rods