How do Fungi and Molds differ from bacteria?
- Cell wall is different
- Mostly aerobic
- Reproduce by budding, not mating
- Do not produce exo/endotoxins
What is the response of the body after exposure to fungi?
Formation of a granuloma
Explain the granuloma formation
- After phagocytosis by macrophages, yest replicates 15-18 hrs
- As host immunity response develops, yeast growth ceases 1-2 weeks exposure
- Delayed-type hypersensitivity to histoplasma entigens 3-6 weeks
- Over weeks to months, inflammatory resonse produces calcified fibrinous granulomas with areas of caseous necrosis
Why is candida albicans considered an opportunistic yeast infection?
Because it is in the normal flora of many health people.
Where does candida albicans reside in the human body?
skin, GI tract, MouthVagina
What type of environment does a fungus need to survive?
High pH, Antibiotics, skin invasion with warm, moist areas, (think skin folds)
What is the term used to describe amebas, sporazoans, flagellates, cillates?
What is the term used to describe Flatworms and round worms?
What are two common intestinal protozoas?
What is the mode of transmission for amebic dysentery
Unwashed fruit and vegetables
What are symptoms of amebic dysentery?
- Bloody mucous diarrhea
- abdominal pain
- Tenesmus (painful defecation)
Describe the pathogensis of amebic dysentery
- Invade colon epithelium
- secrete enzymes that leds to localized necrosis
- Progress into submucosa
- Reach portal circulation and leads to liver abscess
Describe the mode of transmission for Giardia
Fecal contaminated water
Describe pathogenesis of Giardia
- Ingested, but does not invade
- Leads to protein and fat malabsorption
- Has flagella and suction disk that causes local inflammation.
What are the symptoms of Giardia
Nonbloody, foul smelling diarrhea
How many days can Clostridium difficile live on a surface?
Where is Clostridium difficile found?
Hospital - on bedrails, windowsills, floors, toilets, our hands
What are risk factors for C diff?
- Advanced age
- Antibiotic therapy - 2 or more
- Immunosuppressive therapy
- Nasogastric tube
- Use of antacids/proton pump inhibitors
- Prolonged hospital stay
- Recent surgical procedure
- Sharing hospital room with c diff infected patient.
Describe pathophysiology of C Diff
- 1) imbalance of normal bacteria flora of colon
- 2)organism produces exotoxins in intestinal lumen
- * Toxin A activates macrophages and mast cells which inflame colon
- * Toxin B destroys the colon wall
What are the findings on presentation for C diff?
- Begin 4-9 days on antibiotics, can begin up to 8 weeks after
- Focal ulcerations on the colon wall
- Elevated WBC (>15,000)
What is the treatment for C Diff?
- Stop offending antibiotic
- Metronidazole (90% response rate)
- Fluid/electrolyte replacement
- Vancomycin (oral, because IV does not reach the gut)
- Questran binds to toxins