Section 1: Toxins

Question 1

Exotoxin Characteristics

Answer 1

• Toxin secreted by G+ (except Listeria) or G- bacterium; leaks into surrounding fluid after lysis of baterial cell
• bacteria must colonize tissue to produce enough exotoxin to be harmful
• foodborne illness = bacteria multiples in food -> exotoxin
• proteins, thus Immune System (IS) can create antibodies
• most are powerful = fatal before IS
• bacteria that release exotoxin also relase endotoxin (vibrio, e. coli)
• have specific targets!(thus no fever or generalized inflammation (systemic)

Question 2

T/F: exotoxins are denatured by heat

Answer 2

YES - because they are a protein. Since they are a protein remember, that the immune system can also produce antibodies

Question 3

Exotoxin 3 subtypes:

Answer 3

Neurotoxins, enterotoxins, Cytotoxins

Question 4

(Exotoxins): Neurotoxins

Answer 4

• act on nerves or motor end plates to cause paralysis
• bacteria clostridium botulinum (botulism) = flaccid paralysis
• clostridium tetani (tetanus) = spastic paralysis

Question 5

(Exotoxins): Enterotoxins

Answer 5

• act on GI = diarrhea. Inhibit NaCl secretion // kill epithelial cells, thus creating an osmotic pull of fluids iNTO lumen.
• bacteria vibrio cholerae (cholera) = severe watery diarrhea
• bacteria enterotoxigenic E. Coli (Traveler’s Diarrhea) = watery diarrhea
• bacteria Staphylococcus aureus (superantigen; aka food poisoning) = nausea and vomiting

Question 6

(Exotoxins): Cytotoxins

Answer 6

• damage multiple cell types by interfering with cell mechanisms, causing cell lysis.
• • pyrogenic toxins: stim release of cytokines = rash, toxic shock syndrome (streptococcus pyogens Group A streptococci, Staphyloccus aureus)
• • tissue invasive toxins: destroy and tunnel through tissues
• bacteria staphylococcus aureus (wound infections, TSS) = Pus
• bacteria streptococcus pyogenes (pharyngitis, TSS) puss in throat
• bacteria clostridium perfringens (gas gangrene) = extensive tissue damage
• bacteria cornyebacterium diphtheria (diphtheria) = membrane in throat, oragn damage
• bacteria bacillus anthracis (antrax) = inhaled = septic shock

Question 7

Endotoxin Carrot sticks

Answer 7

• endotoxin is lipopolysaccharide (LPS!)
• • LPS = lipid A, core polysaccharide, O specific polysaccharide
• • Lipid A = toxic part responsible for symptoms of endotoxin (100 diff types)
• LPS = in outer membrane in G- bacteria thus VIP part of cell wall
• IS = due to innate immune response, no specific target
• LPS = poor inducer of antibody
• HEAT STABLE, Not destroyed by autoclaving
• Limulus polyphemus proteins used to detect endotoxin (LAL assay)

Question 8

Endotoxin bacteria:

Answer 8

• bacteria salmonella typhi (typhus) = fever, septicemia (blood poisoning)
• bacteria klebisella pneumonia (pneumonia) = fever, cough, chest pain, sputum (saliva and mucus coughed up from respiratory tract) is red
• bacteria haemophilus influenzae (meningitis, ear/respiratory infection) = fever, pain, cough, stiffness
• bacteria campylobacter jejuni (campylobacteriosis) = fever, vomiting, diarrhea
• bacteria escherichia coli (gasteroenteritis) = fever, vomiting, diarrhea