Listeria packet Flashcards
What does facultative intracellular mean?
capable of living and reproducing either inside or outside cells
Where does Listeria live?
Prefers GI and genital tracts.Plants and soil.
Cold growth- soft cheese, deli foods, cabbages. Epidemics may occur in unpasteurized dairy products.
What is Listeria’s motility ?
Tumbling (flagella driven)
How is Listeria transmitted?
Across the placenta or by contact during delivery
What is the treatment for Listeria?
Ampicillin or add gentamicin for IC (immunocompromised) pts.
Describe Listeria monocytogenes. (G+/- ?, motility? intracellular or extracellular? hot/cold environments?rods/cocci?
Nonspore-forming, tumbling, facultative intracellular parasite, cold growth, small gram positive rods
What is the Listeria monocytogenes toxin?
Listeriolysin O – Beta hemolysin
How does Listeriolysin O (LLO) work in Listeria?
Allows Listeria to leave actin jet trails from inside one cell to another.
What type of people are more susceptible to getting Listeria monocytogenes?
Immunologic immature pts (cancer), or pts with renal transplant
Is Listeria monocytogenes aerobic/anaerobic and catalase +/- ?
Aerobic, Catalase +
What are the preventions for Listeria monocytogenes?
Theres no vaccine or drug available. Pasteurize milk or restrict foods.
How does Listeria monocytogenes evade the immune system?
It evades phagocytes by escaping from phagosome to cytoplasm
What is peak season for Listeria monocytogenes?
-Summer because people eat a lot of cold foods
What are the symptoms of Lm?
In healthy adults and children, it can be asymptomatic with low percent carriage.
Pregnant women: asymptomatic carriage, septicemia (fever and chills)
What are the neonatal diseases associated with Lm?
Early onset- granulomatosis infantiseptica –high mortality
Late onset: 2-3 weeks after birth meningitis with septicemia
What Labs are done to diagnosis Corynebacterium diphtheriae?
1-Loeffler’s coagulated serum medium 2-Tellurite-containing medium
3-Elek test
What do we look for in an Elek test?
To see if the growth of the patient’s (unknown) smear resembles either the known toxic diptheriae or the known nontoxic diptheriae smear
What is does C. diptheria look like on a Tellurite medium?
gray-black colonies (also seen this way on throat)
What does a positive Loeffler’s coagulated serum medium show?
Cells with metachromatic granules
What shape is Corynebacterium diphtheriae?
Koryne is greek for “club” and bacterium means “little rod”
what do Corynebacterium diphtheriae and Listeria have in common?
Both are gram +, aerobic, catalase +, nonspore forming rods
what is the pathogenesis of Corynebacterium diphtheriae?
Exotoxin that inhibits protein synthesis in eukaryotes
what is one difference btw Corynebacterium diphtheriae and Listeria?
Listeria has a tumbling motility whereas C. dip is nonmotile
what can Corynebacterium diphtheriae cause?
Diptheria! (and has symptoms of sore throat, pseudomembrane in the pharynx, myocarditis and neural palsies
why is Corynebacterium diphtheriae toxic?
Because it contains a toxin-producing strain of a Beta-prophage (virus living in bacteria that integrates the toxin-encoding genetic elements into the bacteria )
How can we prevent ourselves from getting diphtheriae?
Get a toxoid vaccine or DPT (diptheria, pertussis, tetanus)
What drugs do we give a patient with diphtheria?
mucocutaneous-imidazoles or nystatin,
disemination-amphotericin B or fluconazole
What are therapeutic ways to treat diptheria?
Fluids, Oxygen, bed rest, airway monitoring, heart monitoring
How is C. diptheria transmitted?
respiratory droplets that reside in human throat
What are some characteristics of a patient with diptheria?
bull neck, pseudomembrane (a thick gray layer covering the tonsils)
