bacteria: part 2 Flashcards
Normal 3 tpes of naceria
Cocci, bacilli, spiral
How does flagella and pili contribute to virulence
Flagella (movement, attachment) Pili (important adherence factors)
How does biofilms contribute to virulence. Examples
(organized agregrates of bacteria embedded in polysaccahride matricesi. e. Pseudomonas aeruginosa i.e. Staphylococcus epidermidis
Outline neurotoxin wiht examples
act on nerves or motor endplate i.e. Tetanus or Botulinum toxins
What is endotoxin released by
Only produced by Gram-negative bacteria
What is endotoxin
Not a protein but it’s the the lipid A moiety of LPS
What is haemolytic-uraemic syndrome
triad of acute renal failure, hemolytic anemia and thrombocytopenia
What are E.coli strains which release shiga toxin known as
EHEC enterohemorrhagic E. coli
When does human infection with EHEC often occur
occurs through the inadvertent ingestion of fecal matter and secondary through contact with infected humans
Why can a shiga toxin bacteria infection affect gut microbiota
Bacterial ribosomes are also a substrate for StxA and this will result in decreased proliferation of susceptible bacteria might affect the commensal microflora in the gut
When are shiga toxins highly expressed
Toxins are highly expressed when the lytic cycle of the phage is activated (so that the gene can be taken up by lots of E coli)
What is the impact of AAF bunding to enterocytes with regard to human immune response
AAF stimulate a strong IL-8 response
What type of bacteria are TB and legionella pneumophilia
TB=gram +ve Legionella=gram -ve
List common bacterial STI
Chlamydia trachomatis infection Gonorrhoea Syphilis
What type of bacteria is each of Chlamydia trachomatis Neisseria gonorrhoeae Treponema pallidum
Gram neg
What cells does N gonorrhoeae interact with
Establishes infection in the urogenital tract by interacting with non-ciliated epithelical cells
Virulence factor of Campylobacter sp. mostly C. jejuni
Adhesion and Invasion factors, Flagella motility, Type IV Secretion system, Toxin
Important virulence factor with vibrio cholerae
type IV fimbria cholera toxin carried on a phages
How does the cholera toxin work
Binds to enterocyte Through b pentamer to the GM1 ganglioside receptor on enterocyte A/B cholera toxins cleves A1 domain from A2 domain, activating A1. A1 faragment enters cytosol, activates Gsa, continually stimulating AC to produce cAMP. High cAMP activates CFTR… efflux of ions (esp chloride) and water from infected enterocytes Leads to diarrhoea
How does listeria infect
Listeria can enter non-phagocytic cells and cross three tight barriers Intestinal barrier, Blood / brain barrier and Materno / fetal barrier
