Shared Flashcard Set

Details

GI
Gram + Bacteria and Protozoans
26
Microbiology
Graduate
02/21/2011

Additional Microbiology Flashcards

 


 

Cards

Term
Staph Aureus pathogenesis
Definition
• α toxin, exfoliatin, TSST and enterotoxin
• Superantigen
• Acts on neural receptors in upper GI
Term
Bacillus Cereus pathogenesis
Definition
• forms endospores
• EMETIC FORM: fried rice, pasta; heat stabile
• DIARRHEAL FORM: meat/sauce; heat labile
Term
Gram + Bacteria that causes secretory diarrhea
Definition
S. Aureus, B. Cereus, C. Perfringens,
Term
Gram + Bacteria causes both secretory and inflammatory diarrhea
Definition
C. Diff and B. Anthracis
Term
Major cause of food poisoning in the US?
Definition
C. Perfringens
Term
C. Perfringens distinguishing features
Definition
• resistant to heat/cooking for >1 hour- BUFFETS
• double zone of hemolysis
• part of natural flora
• longer incubation 8-18 hours
• rarely have vomiting!
Term
C. Perfringens pathogenesis
Definition
• >12 toxins
• α and θ cause lysis
• enterotoxin
• forms spores
Term
C. Diff Pathogenesis
Definition
• Toxin A: enterotoxin
• Toxin B: cytotoxin
Term
C. Diff distinguishing features
Definition
• Pseudomembrane Formation
• Dx with ELIZA
• Part of natural flora
Term
B. Anthracis pathogenesis
Definition
• Forms endospores
• Poly D-Glu Acid Capsule
• Tri-Part Toxin; protective Ag, lethal and necrotic factor
Term
Staph Aureus distinguishing features
Definition
• Mannitol Fermentation
• Golden Yellow Colonies
• **Ashley potato salad story
Term
Bacillus Cereus distinguishing features
Definition
• Motile
• β hemolytic
• opportunistic pathogen
• infective with >105 org/g in food.
• Transmitted by spores on grains, veggies, pasta, dairy, meats
Term
C. Perfringens
Definition
Forms spores but not endospores
Term
Protozoans
Definition
Cause persistant, intermittent diarrhea in developing areas with poor sanitation and abundant vectors
Term
Flagellates
Definition
Giardia Lambilia-replicate via binary fission
Term
Ameobas
Definition
Entamoeba Histolytica-move via pseudopods and replicate via binary fission
Term
Sporozoans
Definition
Cryptosporidium Parvum, Cylclospora Cayentenenis, Microsporidia: non-motile. replicate via asexual/sexual schizony/sporogony
Term
G. Lambilia Lifecycle
Definition
ingest cysts which form sting-ray shaped trophozoites in D. New cysts form in LI. Sucking disk of troph adheres to enterocytes causing secretory diarrhea
Term
G. Lambilia features
Definition
-withstand filtration and chlorination
-need to be boiled for 1 minute at least
-cysts are infective upon release
-spread easily in daycare (fecal-oral) or while camping
-Sxs: abd pain, n/v/d x 1-3 wks with malabsorption (fatty, foul smelling d)
Term
E. Histolytica lifecycle
Definition
ingest cysts, which form trophozites in LI, then invade mucosa and produce more cysts. Troph in LI destroy RBC and produce protease (inflam diarrhea). Cysts are released in stool.
Term
E. Histolytica features
Definition
-aqr'd via contaminated fruit, water, veggies or by fecal exposure during sexual contact.
-10% ppl are show sxs: flask shaped lesions and dysentary
-can have systemic infection (lung and liver abscess)
-85% are asymptomatic if bacteria is just in the lumen
Term
Cryptosporum Parvum lifecycle
Definition
ingest water contaminated by cysts, ingested oocysts release sporozoites in SI that invade enterocyte vacuoles (only destroy gap junctions)
-oocysts are immediately infective once outside the body
Term
Cryptosporum Parvum features
Definition
-often transmitted in water parks
-most common cause of secretory diarrhea in kids
-may be life threatening in the immunocompromised.
-stain pink in acid fast stain
Term
Cyclospora Cayetanensis lifecycle
Definition
-ingest oocyts which have matured in the environ for at least 1 week.. Cysts continue dev in SI forming sporozoites
Term
Cyclospora Cayetanensis features
Definition
-person to person spread is unlikely
-causes secretory diarrhea x 1-2 wks which may be prolonged, severe.
-dx with PCR assays
-often transmitted on basil, raspberries and other fresh produce
Term
Microsporidia
Definition
-humans ingest or inhale spores which get into gut, lungs or eyes.
-usually infects ppl with low CD4 count
-intracellular spore formation
-causing sev diarrhea, disseminated dz and corneal infections
Supporting users have an ad free experience!