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34 Cards in this Set
- Front
- Back
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T\F
Shigellae requires an unsanitary environment because it requires a high dose for infectivity |
False. Persists in regions with modern plumbing and good sanitation
LOW DOSE PATHOGEN |
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What is the incubation period of Shigellae?
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72 hrs
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What is dysentery? how is it different from diarrhea?
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Dysentery is opposite of diarrhea. Causes tinesmus but small volume at great effort.
blood, mucous and PMN’s in stools, fever, cramps Diarrhea is mostly water |
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What are the characteristics of Shigellae?
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G- rod
Facultative anerobe Nonmotile LACTOSE NON-FERMENTER |
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How can you distinguish E. Coli from Shigella in a mixed culture?
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Shigella is a lactose non-fermenter.
Shows up white on Maconkey E.coli is red |
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What are the Virulence factors of Shigella?
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Enterotoxins-causes diarrhea
Surface O antigen Shiga toxin Actin binding protein |
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What is the function of the Surface o antigen of Shigellae?
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Allows it to enter intestinal cells via binding M cell antigen receptors which then present Shigella to immune cells.
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How does Shigella handle host phagocytes?
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It enters them then lyses them. Causing inflammatory response leading to bleeding , cell removal and drawing of PMN's.
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If Shigella is nonmotile how does it move from cell to cell?
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using Actin binding protein. Adheres to actin and forces polymerization that propels it
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What does Shiga Toxin do
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Disruption of protein synthesis and damage to intestinal epithelium
-Cleaves large ribosomal subunit |
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What is unique about the presentation of a patient with Shigellosis?
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Dysentary- PMNs, Blood and mucous in feces with acute onset
-other diarrheal diseases do not cause true dysentary |
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What would a Sigmoidoscopic exam reveal about a patient with shigellosis
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multiple shallow ulcers
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What is the treatment for shigella and why is antibiotic therapy probplematic?
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Fluid replacement-it is self limiting
Inappropiate antibiotic linked to HEMOLYTIC UREMIC SYNDROME |
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What are the 3 most common complications of Shigellosis?
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-Reiters Syndrome-urethritis, polyarthritis, inflammatory eye disease, skin lesions
-HUS due to antibiotic therapy -Autoimmune disease |
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What is the reservoir for this agent and mode of transmission? IMPORTANT!!
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Humans are sole reservoir
Transmission=P2P(Fecal oral) |
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What are the 2 most common species of Shigella? Main location each is found
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S. flexneri-children
S. sonnei-Gay males |
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Epidemiology- what demographic has the highest incidence of Shigella?
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Children 1-4 yo
85% of cases |
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What is the single most important control measure of Shigellosis?
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hand washing
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Where is Salmonella found and why is it a major concern?
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-ubiquitous
-part of gut flora of many birds and animals Emerging problem and level of infection is increasing |
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What is the incubation time of Salmonella? Duration?
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12-48 hrs
2-3 days |
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What age groups is Salmonella disease more severe?
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Infants and elderly
Immunocompromised also at greater risk |
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Describe Salmonella
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G- rod
Facultative anaerobe MOTILE LACTOSE NON-FERMENTER |
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What will happen to a agar containing S Typhimurium when plated with Iron sulfide?
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Will turn agar black via H2S production
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How is shigellas route of entry different than Salmonella?
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Can enter via M-cells of peyers patches or intestinal epithelial cells
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How does Salmonella deal with phagocytosis differently than Shigella?
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Doesn't lyse
Can tolerate living in them |
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How does Salmonella enter intestinal cells?
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Mucosal invasion genes- induces cell cytoskeletal changes causing engulfment of bacterium
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What are the 2 Virulence factors important to Salmonellas survival in phagocytes?
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Acid resistancde
phoPQ-controlled genes for phagocyte survival |
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What is the most important item to sample in Diagnosis of Salmonella disease?
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Food Items
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How is Salmonella treated?
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Maintain fluids and electrolytes
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Where does Salmonella primarily come from?
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ususally a disease of DEVELOPED countries via improper handling of food
also PETS-dogs cats reptiles |
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Why is it important for AIDS patients to be cautioned about pets?
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Salmonella vectors
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Is salmonella a High dose or low does organism?
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HIGH DOSE
10^5 TO 10^9 |
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Does Salmonella have a seasonal component?
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increases in Summer and Fall
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What foods should immunocompromised patients be warned about?
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Fresh fruits and vegetables, Alfalfa, Tomatoes and eggs
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