Infectious Disease 5

Both Salmonella and Shigella are
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Terms in this set (19)
Both Salmonella and Shigella are
enteric pathogens
Salmonella colonize and invade the
small bowel
salmonellosis ranges clinically from
gastroenteritis, to life-threatening enteric fevers (incl. typhoid fever)
Non-typhoidal salmonellosis (i.e. gastroenteritis) is a
worldwide disease of humans and animals
Many strains can cause the disease salmonellosis all are all from the species
Salmonella enterica
No vaccines for Salmonella but there are many options in the
spectrum of antibiotic chemotherapy
Various mechanisms for breaching gut epithelia are used by Salmonella including
Induced invasion, transcytosis, and phagocytosis
Species of Shigella (dysenteriae, flexneri and sonnei) also invade the
intestine causing acute gastroenteritis (dysentery)
Dysentery kills an estimated
0.5 to 1 million children (<5 years) per year
Like salmonella no vaccines for shigella but many
first line antibiotics for treatment of dysentery if antibiotics are available and rehydration and electrolyte therapy are used as well
Like Salmonella, Shigella invades through the intestine—then replicates inadjacent intestinal cells by lateral propagationShigella replicates in cytoplasm, and invades adjacent cells by lateral propagation—this is achieved bypolar condensation of actin3 most common mechanisms for toxin damage areImmunopathological, cell death/cell damage, and pharmacological damageThree important toxins include :Shiga toxin, E. coli LT-I, Pertussis toxinMembrane-damaging (ex. Pore-forming toxins, PFTs) haveBroad target range and toxicity and usually are CytotoxicIntracellular-acting(ex. AB toxins) work bySpecific effect and cellular targets, Receptor mediated uptake internalization or translocation, Hit intracellular target(s) and may or may not be cytotoxicPFT A large group of toxins that formpores in the membranes of bacteria, plants and mammals and cause membrane permeability and ion imbalanceAB organization of toxinsThe A domain (aka effector) is commonly an enzyme or a factor that directly interacts with a host protein(s) andThe B domain comprises thereceptor-binding function which provides tropism to specific cell types