QTR 3 Block 2: Intro to Bacteriology Flashcards
What part of a bacterium is generally the most effective in generating an immune response?
lipopolysaccharide in the cell wall
Describe the cell wall of Gram + bacteria.
Thick Peptidoglycan layer that is external to the cell membrane. Has lipoteichoic and teichoic acid in the wall.
Describe the cell wall of Gram - bacteria.
thin peptidoglycan inbetween the inner and outer membrane, and a periplasmic space.
Describe the Gram staining process.
First add crystal violet, then Gram’s Iodine, then decolorize with ethanol (the thick peptidoglycan in gram + bacteria will retain the dye. Then counterstain with Safranin red, which will stain everything else. Therefore, purple-blue bacteria are POSITIVE.
What are some significant roles played by lipoteichoic and teichoic acid found in the gram + cell wall?
important in virulence and viability, promotes attachment to specific host receptors, sheds in the host but generates a relatively weak immune response.
Describe the bacterial capsule present in the SHiNS pathogens.
it is essentially a loose polysacharride layer …VERY important for virulence. promotes adherence and is anti-phagocytic
What bacterial structure is an H antigen and is highly antigenic? (Hint: confers motility).
Flagella
Describe the asymmetric design of the gram - cell membrane.
The outer membrane is primarily LPS, separated from a normal lipid bilayer inner leaflet by the periplasmic space.
When a host cell senses _______ it turns on EVERY defense at its disposal…and some.
LPS
Describe the periplasmic space in Gram _ bacteria.
It is an area containing transport systems for iron, proteins, sugars, and containts hydrolytic enzymes and virulence factors. Also has PORINS, which allow diffusing of small hydrophilic particles.
What component of a bacterial wall determines its acid fastness?
mycolic acid in the lipid coat (specifically the c-chain)
Describe the obligatory steps for bacterial infection.
Acquisition/ Colonization, Infection, Replication, Dissemination/Disease, Treatment (ACIRD-T)
What are some common ways of transmitting bacterial pathogens?
coughing. sneezing, talking (consonants F, P, T, S), living conditions
Describe different vectors of acquisition of bacterial pathogens.
Inhalation, ingestion, travel, STD, Surgical, Zoonosis, Needle Sticks
What are some basic factors influencing the outcome of a bacterial infection?
Strain, inoculum size, length of presence, host factors
