Term
| What are the major differences between Endotoxins and Exotoxins? |
|
Definition
1) Endotoxins are part of LPS/LOS and are heat-stable
2) Exotoxins are secreted, very toxic and heat-labile |
|
|
Term
| Which bacteria are Enterotoxin producers? |
|
Definition
1) Bacillus cerus (food poisoning for emetic and diarrheal)
2) Staph aureus (Alpha toxin)
3) C. dif (A and B)
4) E. coli (ST and LT and STX)
5) Shigella (STX)
6) C perfringens (alpha toxin)
7) Virbrio cholerae |
|
|
Term
| Which enterotoxins increase cAMP leading to fluid secretion?? |
|
Definition
1) Cholera toxin
2) LT of ETEC |
|
|
Term
| Which enterotoxins increase cGMP leading to fluid secretion?? |
|
Definition
|
|
Term
Which enterotoxins act as super-antigens?
What about tight-junction permeability through signal transduction changes? |
|
Definition
1) S. aureus Exotoxin A
2) C dif. A and B |
|
|
Term
| What is the toxin/action utilized by B. anthracis? |
|
Definition
Protective Antigen (binding subunit)
EF (adenylate cyclase)
LF (protease) |
|
|
Term
| What is the toxin/action utilized by B. pertussis? |
|
Definition
1) Bacterial adenylate cyclase
2) Pertussis toxin (ADP-ribosylation of Gi protein, activating adenylate cyclase) |
|
|
Term
| What is the toxin/action utilized by C. botulinum? |
|
Definition
| Botulinum neurotoxin (protease that causes flaccid paralysis by blocking Ach release) |
|
|
Term
| What is the toxin/action utilized by C. difficile? |
|
Definition
Enterotoxin (A)
Cytotoxin (B)
**Monoglucosyltransferases that add glucose to rho proteins** |
|
|
Term
| What is the toxin/action utilized by C. perfringens? |
|
Definition
1) Alpha toxin (PLC)
2) Enterotoxin- Damage membranes
3) Beta toxin (Pore-formation) |
|
|
Term
| What is the toxin/action utilized by C. tetani? |
|
Definition
| Tetanus Neurotoxin (protease that inhibits inhibitory Neurotransmitters- spastic paralysis) |
|
|
Term
| What is the toxin/action utilized by C. diptheriae? |
|
Definition
| Diptheria toxin (ADP-ribosylates EF-2 to inhibit P-synthesis) |
|
|
Term
| What is the toxin/action utilized by E. coli? |
|
Definition
1) Shiga (blocks p-sythesis by inhibiting ribosomes)
2) ST (cGMP)
3) LT (cAMP like cholera)
4) Hemolysin (Pore-former) |
|
|
Term
| What is the toxin/action utilized by L. monocytogenes? |
|
Definition
| Listeriolysin O (Streptolysin-like action to break open phagosome) |
|
|
Term
| What is the toxin/action utilized by P. aeruginosa? |
|
Definition
| Exotoxin A (like-diptheria to ADP-ribosylate EF-2_ |
|
|
Term
| What is the toxin/action utilized by S. dysenteriae? |
|
Definition
| Shiga toxin (Inactivates 60S ribosomal subunit to inhibit protein synthesis) |
|
|
Term
| What is the toxin/action utilized by S. aureus? |
|
Definition
1) Alpha toxin (Hemolysin to damage membranes)
2) Enterotoxin (Vomiting and diarrhea as super-antigen)
3) TSST-1 (Superantigen)
4) Exfoliatins (Scalded skin syndrome) |
|
|
Term
| What is the toxin/action utilized by S. pyogenes? |
|
Definition
1) Streptolysin O (membrane lysis)
2) Erythrogenic A and C (scarlet fever/super-antigen)
(Pyrogenic A and C) |
|
|
Term
| What is the toxin/action utilized by V. cholerae? |
|
Definition
| Cholera toxin (ADP-ribosylation of Gi, leading to adenylate cyclase activation). |
|
|
Term
| Which Pairs of Exotoxins have similar actions? |
|
Definition
1) Pertussis and Cholera (ADP-ribosylate Gi to activate adenylate cyclase) (also C. jejuni)
2) Diptheria and Exotoxin A (ADP-ribosylate EF-2 to inhibit p-synthesis)
3) ST and Y. enterocolitica (guanylyl cyclase)
4) |
|
|
Term
| Where do Botulinum and Tetanus toxin exert their actions? |
|
Definition
1) Tetanus at spinal chord (spastic)
2) Botulinum at NMJ (flaccid) |
|
|
Term
A patient presents with double-vision after eating a strange meal. Soon after, he develops descending paralysis.
What is the pathogenesis of this bug? |
|
Definition
C. botulinum serotype- Most common in infants, begining with constipation
1) Heat-resistant spores produce heat-sensitive toxins
2) Ingestion-intoxication where Botulinum toxin (E has vomiting) acts at NMJ to prevent Ach release. |
|
|
Term
| Where do you most commonly see botulism in the US? |
|
Definition
In Soil and food-borne
infants (start with constipation) and in Alaska |
|
|
Term
| What treatment/prevention methods are available for Botulism? |
|
Definition
1) Antitoxin, Supportive (10% fatality with treatment with no long-term sequele)
2) Don't feed infants honey, prepare food carefully
- Vaccine available for special situations. |
|
|
Term
| Which bacteria make Pore-producing Hemolysins and Eznymatic Hemolysins that act on membranes? |
|
Definition
Many effect WBC as well as RBC
1) Most gram-positive (Listeriolysin and Streptolysin O)
2) Staph aureus (Alpha toxin)
3) Uropathogenic E. coli make alpha hemolysin
4) C. perfringens makes alpha toxin (PLC) |
|
|
Term
| Which toxins mediate mammalian protein synthesis? |
|
Definition
1) Pseudomonas (Exotoxin A ADP-ribosylates EF-2)
2) Diptheria (ADP-ribosylation of EF-2)
P-synthesis shuts down and cells die!
3) Shiga toxin and Shiga-like toxin (EHEC) inactivates ribosome at 60s rRNA subunit |
|
|
Term
| What is the mechanism of action of DIphtheria toxin? |
|
Definition
1) A-B binds receptor on host
2) Endocytosis and Acidification of endosome leads to A release
3) A exerts toxic activity on EF-2, halting P-synthesis |
|
|
Term
A patient with a moderately sever wound dies of sudden-onset septic shock.
Gram stain reveals gram-negative, motile rods that make blue-green pigments.
What are the virulence factors of this pathogen? |
|
Definition
Psuedomonas aerginosa!
1) Exotoxin A (P-synthesis causing necrosis)
2) Enzymes (Proteases and elastase for tissue damage)
3) Leucocidin (WBC inhibition)
4) PLC (Hemolysin that affects WBC as well)
5) Endotoxin (shock- fairly week in comparison to others)
6) Capsule (biofirm that contributes to cystic fibrosis)
7) Pili (Adhesion) |
|
|
Term
| What is the transmission/reservoir of P. aeruginosa? |
|
Definition
1) Ubiquitous in environment
2) Can't penetrate epithelium, so goes through wounds, surgical incisions and burns. |
|
|
Term
True or False:
P. aerginosa infection is seen primarily in immunocompromised individuals. |
|
Definition
True (Septicemic infections with shock that have high mortality)
WBC can usually resist, but in case of CF, burns, and catheters (UTIs)/IVs, it is a problem. |
|
|
Term
| How to you treat/prevent P. aerginosa infection? |
|
Definition
1) Supportive for shock and then appropriate drugs (50% resistant at UPMC to quinolones or aztreonam and 20% to other IV drugs)
2) Hygiene with topical agents to prevent wound infections (silvadene)! No vaccine |
|
|
Term
| How can Gram-positives induce shock/fever/ect. despite lacking Endotoxins? |
|
Definition
Superantigens!
1) TSST-1 in Staph
2) Streptococcal Erythrogenic toxin (scarlet fever) |
|
|
