Lc 12 Flashcards
List traits of corynebacterium
Gram positive cocci
Non branching
Clumps
Aerobic
Is corynebacterium nonmotile and non sporulating?
Yes
In corynebacterium, humans are the ONLY reservoire. True or false
True
What is its spreading mechanism?
Respiratory droplets, cutaneous lesions, and fomites like desk surfaces
Pharyngeal/ nasal carriage in some convalescent cases
Corynebacterium’s virulence factor and its function
DT(diphtheria) toxin
—>Classic AB subunit toxin:
B unit: cell binding( R) , translocation(T) —-> toxin delivery via endocytosis
A unit: catalytic (C) ——>pathogenicity/cellular effects in host cells
Elongation factor 2 : stops host cell protein synthesis —> cell dies
Is DT encoded on lysogenic bacgeriophage?
YES
DT regulates production of toxin. Is it chromosomal encoded or phage encoded?
Chromosomal encoded
If our body is infected, our body will have low ___
Iron
—> anytime the organism is making toxin that kills cells, it is upregulating the ability to acquire and utilize iron.
Corynebacterium use DT toxin to destroy host cell and acquire iron. True or false?
True
Local toxic effects of diphtheria
Sore throat (pharyngitis)
Cells are destroyed, debris formation,
Form yellow pseudomembrane on your tongue
Systemic toxin effects of diphtheria
Myocarditis( heart disease) —> pump disfunction, shortness of breath
Soft palate and diaphragm paralysis,
Corynebacterium also causes skin infections. How do you diagnose the disease?
Isolate from lesions by culture on selective media
Use use tinsdale agar, and dark brown and
Black colony will show up.
How do we prevent this disease?
Use vaccination(DTaP)
Vaccine is toxoid!
What does toxoid do?
It inactivates B subunit which then causes A subunit to be not toxic,
So the toxoid blcoks the activity of uptake and activity of toxin but it doesn’t eliminate the ability to colonize or being antigenic. It still cause infection.
But ATTENUATES infection
What is the main mechanism of toxoid?
When it slows the toxin capabilities of then toxin, we effectively buy time for the host to mount protective immune response and get rid of the bacteria that are producing it.
What does corynebacterium jeikeium disease cause?
-Skin infection
-bacteremia (blood), endocarditis(heart), pneumonia( lung), osteomyelitis (bone), meningitis (centeal enrvous system)
- nosocomial infections
Listeria monocytpgenes characteristic
- short gram positive rod, catalase positive
- beta hemolytic , grows at low temp, pH, and High salt
-intestinal colonization
What is lysteria’s spreading mechanism?
Internalins: InlA ans InlB allow binding and entering to host cells
Listeriolysin O : helps listeria grow in cytoplasm by lysing phagosome (form a pore)
ActA: polar distribution(actin polymerization), —> key for cell to cell spread(helps release to cytoplasm)
Lysteria is mainly what kind of disease?
Food borne
What does the food borne infection do to pregnant women and their fetuses?
Vertical transmission,
-early onset: utero
-late onset : during birth. Causes meningitis
What kind of people are susceptible to listeria?
Elderly,alcoholics,diabetes,corticosteroid users —> those with compromised cellular immnunity
Likely to have meningitis and septicemia(blood poisoning)
People with immune competent body have what kind of infections?
Gastrointestinal infections, mild flu
If you get septices and meningitis, it is very difficult to combat. True or false?
True
How do you diagnose listeria?
Culture of cerebral spinal fluid, blood, amniotic fluid, placenta, fetal tissue
Bacillus cereus characteristics
Gram positive rod, but when decolorized, it looks like gram negative rod.
-aerobe, beta-hemolytic, motile, spore former
-widely distributed throughout nature
What does the spore do?
Heat and dessication resistant
Metabolically inactive
Withstands autoclaving
Germinate into cells after decades of persistence
Bacillus has enterotoxins. Enterotoxins are harmful to your digestive systems. What are their characteristics?
Heat stable toxins- acid tolerant, emetic form like vomiting
Heat labile toxins- diarrheal illness
