Gi-micro – Microbiology Definitions – Flashcards
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Unlock answersHow is Staph differentiated from strep? How is S. aureus distinguished from all other staphylococci? |
Strep grow in chains Strep are Catalase(-) No other staph species are coagulase(+) |
| What are the laboratory characteristics of Staph aureus? |
Gram(+) cocci in grape-like golden clusters Beta-hemolytic on blood agar Coagulase and Catalase (+) |
How many types of Staphylococcal enterotoxins are there? What is the pathogenesis of the toxins? |
6 distinct serological types Pathogenesis Induces Peristalsis and Diarrhea Stimulates Vomiting Superantigen activity causing toxic shock syndrome |
What are the lab characteristics of Bacillus cereus? What typical foods does bacillus cereus affect? |
Lab: Aerobic, Large spore-forming, Gram(+) Rods Foods: Rice, or meat dishes
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What are the food poisoning syndromes that are produced by Bacillus cereus? What are the causative toxins? What foods are they typically found in? Which syndrome appears faster? |
Emetic(similar to staph food poisoning) Heat-stable Enterotoxin Found in grains and rice Appears faster(in 4 hrs) similar to Staph Diarrheal Type(Similiar to Cholera and E.coli) Heat-labile Enterotoxin increasing cAMP Meat, Vegetables and Sauces Takes longer to appears(24 hrs) |
What are the lab characteristics of Clostridium botulinum? What foods does it typically affect? |
Anaerobic Gram (+) Spore-forming Rod Alkaline, Anaerobic(Canned) Vegetables |
What is the structure, and mechanism of Botulinum toxin? How many serotypes are there |
Structure: AB Mechanism: Prevents Ach release causing flaccid paralysis Serotypes: 8
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What is the different syndromes caused by Clostridium Botulium? Which is most common? |
Food Borne: 12-36 hrs onset of GI Symptoms Followed by descending paralysis Wound Botulism 4-14 days same presentation w/o GI symptoms Infant Botulism(Most Common) Honey-> Floppy Infant Syndrome |
| What ar ethe treatment modalities for Botulism and when are each implemented? |
Respiratory Support: as needed Penicillin: Not to Infants Only if organisms present Antitoxin: Not to infants Food-borne and wound botulism Botulism Immune Globulin Intravenous: Human Ig for infant botulism A and B |
What is the mechanism of: Shiga Toxin Cholera Toxin LT enterotoxin ST enterotoxin E.coli cytotoxin Botulinum toxin Staph Enterotoxin B.cerues Heat stable B.cereus Heat-labile Y.enterolytica Enterotoxin |
Shiga Toxin: AA-tRNA Receptor site block Cholera Toxin: AB with ADPR-transferase for AC increasing cAMP LT enterotoxin: AB ADPR-transferase for AC ST enterotoxin: Activates GC E.coli cytotoxin: Shiga like toxin Botulinum toxin: block Ach release Staph Enterotoxin: Peristalsis/Vomit/Superantigen B.cerues Heat stable: Staph enterotoxin like B.cereus Heat-labile: cAMP like Cholera Y.enterolytica Enterotoxin: E.coli ST like |
| What are the noninvasive and Invasive common GI pathogens |
Non-Invasive C. diff Cholera EHEC ETEC H. pylori
Invasive Shigella Salmonella EIEC V.parahaemolytics Yersina enterolytica Campylobacter jejuni |
