Bacterial Pathogens Flashcards
what is the function of bacterial toxins?
to cause symptoms of disease that are beneficial to the pathogen and toxic to human cells.
what is a cytotoxin?
toxin that affects a range of cell types
what type of bacteria has lipopolysaccharide?
Gram negative
what are the main structural components of lipopolysaccharide?
lipid A, core polysaccharide, up to 40 O antigen repeats
what part of lipopolysaccharide structure is associated with toxicity?
Lipid A
what part of lipopolysaccharide structure is associated with immunogenicity?
polysaccharide components
what illness does lipopolysaccharide cause?
septic shock
what is the cause of death in septic shock patients?
failure of organs such as the heart, lungs, brain and kidneys
what is the first stage of septic shock?
what is the second stage of septic shock?
what is the third stage of septic shock?
what is the fourth stage of septic shock?
what causes the leakage of fluids into surrounding tissue in sepsis?
what causes inability to regulate blood flow and pressure in sepsis?
what is the impact of widespread triggering of coagulation in sepsis?
what disease does Bordatella pertussis cause?
Whooping cough
during what stage of growth can pathogens shed part of their cell wall?
logarithmic phase
what is the main toxin in whooping cough and what kind of molecule is it?
Bordatella tracheal cytotoxin (TCT). low molecular weight glycopeptide from the cell wall peptidoglycan
what is the impact of bordatella tracheal cytotoxin (TCT) on the body?
ciliostasis - cilliary movement is stopped, removal of ciliated cells, causing violent coughing episodes as this becomes the only way to remove inflammatory debris, mucus and bacteria. release of IL-1.
what is the main toxin in Mycobacterium ulcerans infection and what kind of molecule is it?
mycolactone, polyketide derived macrolites produced as secondary metabolites.
what is the disease caused by Mycobacterium ulcerans?
Buruli ulcer - progressive necrotic lesions that can cover 15% of the body
how are mycolactones encoded in the bacterial dna?
they are encoded on a 174kb plasmid which encodes 3 polyketide synthases (MLSA1, MLSA2, MLSB) and 3 polyketide modifying enzymes. The MLSA domains encode the core of the molecule and the MLSB domain encodes the side chain.
what is the histopathology of a buruli ulcer?
a tissue punch biopsy will show an intact dermis and necrotic subcutis with fat cell ghosts and edema. the epidermis will show epidermal hyperplasia and a band of extracellular ZN positive acid-fast bacteria is present in the deep layer of the necrotic subcutis.
how does mycolactone suppress the host immune response?
prevents protein translocation into the ER, therefore blocking production of secretory proteins like TNFa as they then get degraded in the cytosol by the ubiquitin:proteasome system.
how does mycolactone produce an analgesic effect?
how does mycolactone impact actin assembly and the cell matrix?
what is the definition of a type I toxin?
a toxin that does not enter the cell.
what bacterium produces toxic shock syndrome toxin?
Staphylococcus aureus
what type of toxin is toxic shock syndrome toxin?
type I superantigen
how do superantigens cause disease?
what is the function of type II toxins?
what are a-pore forming toxins?
what are b-pore forming toxins?
how do pore-forming toxins enter the membrane and create pores?
what is the function of phospholipases?
what is an example of an infection that uses phopholipase and what is the impact on the host tissue?
what are type III toxins?
what toxins are produced by Clostridium tetani and what disease does it cause
Tetanospasmin (TeNT) - a potent neurotoxin and tetanolysin - a haemolysin. Tetanus
how does TeNT travel though the body and enter the nervous system?
what is the impact of TeNT at the neuromuscular junction?
what are the 6 main steps of the TeNT mechanism of action?
what is the impact of TeNT cleavage of synaptobrevin?
what toxin is produced by Clostridium botulinum and what disease does it cause?
BoNT, botulism
what is the basic structure of BoNT and how is it activated?
how does BoNT move through the body and enter the nervous system?
what is the BoNT mechanism of action?
what is the impact of BoNT on the host?
what toxins are produced by Vibrio cholerae and what disease does it cause?
cholera toxin (CTX), Zot, Ace. Cholera
what is the structure of cholera toxin?
what is the mechanism of action of cholera toxin?
what is the impact of cholera toxin on the host?
what is a toxoid vaccine?
what are some common toxoid vaccines?
what is the dosage of the DPT vaccine?
