microbiology toxins

Question 1

Corynebacterium diphtheriae

Answer 1

diphtheria toxin

Pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck)

Question 2

Pseudomonas aeruginosa

Answer 2

toxin A

Host cell death

Question 3

Shigella spp.

Answer 3

shiga toxin st

GI mucosal damage Ž dysentery; ST also enhances cytokine release, causing hemolyticuremic syndrome (HUS)

Question 4

Enterohemorrhagic E coli

Answer 4

shigs like toxin (SLT)
SLT enhances cytokine release, causing HUS (prototypically in EHEC serotype O157:H7). Unlike Shigella, EHEC does not invade host cells

Question 5

Enterotoxigenic E coli

Answer 5

heat labile toxin (LT) ,and heat stable toxin (ST)

watery diarrhea

Question 6

Bacillus anthracis

Answer 6

edema toxin

Likely responsible for characteristic edematous borders of black eschar in cutaneous anthrax

Question 7

Vibrio cholerae

Answer 7

cholera toxin

Voluminous “rice-water” diarrhea

Question 8

Bordetella pertussis

Answer 8

pertussis toxin
Whooping cough—child coughs on expiration and “whoops” on inspiration (toxin may
not actually be a cause of cough; can cause “100-day cough” in adults)

Question 9

Clostridium tetani

Answer 9

tetanospasmin
Toxin prevents release of inhibitory (GABA and glycine) neurotransmitters from Renshaw cells in spinal cord Ž spastic paralysis, risus sardonicus, trismus (lockjaw)

Question 10

Clostridium botulinum

Answer 10

botulinum toxin

Toxin prevents release of stimulatory (ACh) signals at neuromuscular junction Ž flaccid paralysis (floppy baby)

Question 11

Clostridium perfringens

Answer 11

alpha toxin

Degradation of phospholipids Ž myonecrosis (“gas gangrene”) and hemolysis (“double zone” of hemolysis on blood agar)

Question 12

Streptococcus pyogenes

Answer 12

streptolysin o
Lyses RBCs; contributes to β-hemolysis; host antibodies against toxin (ASO) used to diagnose rheumatic fever (do not confuse with immune complexes of poststreptococcal glomerulonephritis)

Question 13

Staphylococcus aureus

Answer 13

Toxic shock syndrome toxin (TSST-1)
Toxic shock syndrome: fever, rash, shock; other toxins cause scalded skin syndrome (exfoliative toxin) and food poisoning (heat-stable enterotoxin)

Question 14

Streptococcus pyogenes

Answer 14

Erythrogenic exotoxin A

Toxic shock–like syndrome: fever, rash, shock; scarlet fever

Question 15

Endotoxin

Answer 15

LPS found in outer membrane of gram ⊝ bacteria (both cocci and rods). Composed of O antigen + core polysaccharide + lipid A (the toxic component).
Released upon cell lysis or by living cells by blebs detaching from outer surface membrane (vs exotoxin, which is actively secreted).
Three main effects: macrophage activation (TLR4/CD14), complement activation, and tissue factor activation.

Question 16

Endotoxin

Answer 16

ENDOTOXINS: Edema Nitric oxide DIC/Death Outer membrane TNF-α O-antigen + core polysaccharide + lipid A eXtremely heat stable IL-1 and IL-6 Neutrophil chemotaxis Shock