L8: Bacterial Pathogenicity Flashcards
_____: Sum of the characteristics that allow bacterium to produce disease (biochemical, structural, genetic)
Virulence
What are the two primary bacterial defense strategies?
1.Colonize and invade host surfaces
2. Evade complement, phagocytes, and antibody response
True or False: For a pathogen to penetrate intact skin, there has to either be disruption of skin (catheter, surgery) or transmission by arthropods (B. burdorfi, Lyme)
True
What do most bacteria have that makes it easier for mucin to trap them?
Mucin binding surface
What three features do bacteria that are able to EVADE trapping by mucin have?
- Lack mucin receptors
- Make mucin-degrading enzymes (hydrolases)
- Move between mucin strands
True or False: Colonic bacteria (clostridia, enterobacteria, B. fragilis) tend to be good at evading trapping by mucin layer
True
_____: small cysteine-rich cationic proteins, a natural bactericidal, that create PORES in bacterial membranes + diffuse through porins and peptidoglycan to reach CYTOPLASMIC MEMBRANE
Defensins
____, which has a negative charge, binds defensins and prevents them from reaching the cytoplasmic membrane
A. TLR
B. LPS
C. Olg gene
D. Bacterial membranes
B. LPS
What are two ways that the bacterial cell gets rid of defensins?
(hint: enzymes and pumps)
- Peptidase degrades it
- Cytoplasmic proteins pump them out
Which immunoglobulin molecule makes mucin sticky + binds bacterial antigens (via ABC and interact w/mucin via their Fc portions)?
A. sIgG Protease
B. sIGB Protease
C. sIGD Protease
D. sIGA Protease
D. sIGA Protease
Bacteria produce extracellular enzyme that
cleave ___ at hinge region, breaking links
between bacteria and mucin
IgA
What are the two type of microbial adhesion factors that exist?
Protein and Polysaccharide
Are Flagella, Fimbrae, Pili, S Layer, and Afimbrial polysaccharide or protein adhesions?
A. Polysaccharide Adhesions
B. Protein Adhesions
B. Protein Adhesions
True or False: The capsule and cell wall are protein adhesions
False - polysaccharide
True or False: Afimbriae, Flagella, Fibriae, and Pili are all appendages
True
Where in bacteria is the S Layer Found?
A. Cell envelope
B. Cell wall
C. Cytoplasm
D. Outer Membrane
A. Cell envelope
True or False: In medical situations, adhesions would be considered a major determinant of virulence for many pathogens
True
Which two rod-shape, hair-like protein structures on surface of
bacteria mediate attachment?
Pili and fimbriae
Tip structure of fimbriae and pili attaches specifically to receptor on host
cell, often carbohydrate residues of ____ or ___
glycoproteins or glycolipids
True or False: Fimbrae play vital role in conjugation ; comprise subunits
called pillin that forms a canal that allowed exchange of DNA between two bacterial cells; serves as receptors for certain viruses (bacteriophage)
False - Pili !
Which is found in greater abundance in the bacteria cell and is specialized for attachment of bacteria to its host?
A. Pili
B. Fimbriae
C. Flagella
B. Fimbriae
Pili are constantly lost and reformed (due to fragility). How does this help bacteria avoid host defenses?
Change pilus type by altering antigenicity
True or False: Pili and Fimbriae allow bacteria and host cell to form initial loose
contact, triggering mechanisms of tighter adherence
True
True or False: Mostly gram-positive pathogen (E.coli - urinary tract
infections and gastroenteritis), V. cholera,
P. aeruginosa, and Neisseria spp have fimbrae and pilli
False - gram negative!
After adhesion in a bacterial cell, there is ____ ____. What are the two outcomes?
signal transduction
- Host alters gene expression in response to adhesion binding
- +/- virulence genes of bacterial cell
_____: Cells surface proteins that do not form
pili
A. Apillus
B. Afimbrial
C. Aflagellar
B. Afimbrial
True or False: Afimbrial cells likely mediate WEAKER binding of bacterial and host cells
and may bind proteins on carbohydrates rather than host cells
False - Afimbrial cells likely mediate TIGHTER binding of bacterial and host cells
and may bind proteins on HOST CELLS
rather than carbohydrates
Yersinia, Neisseria, E. coli, and Strep/Staph all share which feature?
A. Apillus
B. Afimbrial
C. Aflagellar
B. Afimbrial
___: filamentous protein structures that provide swimming movement for most motile bacterial cells
A. Fibrae
B. Flagella
C. Pili
B. Flagella
Which pathogen has motility and is its determinant of virulence? (swims into intestinal mucosa to avoid being flushed out by peristaltic action of the gut)
A. Strepto
B. Staphylo
C. Vibrio
D. Enterbacteria
C. Vibrio
The distally located flagellar cap protein has been reported to function as adhesins in which three pathogens?
1) E.coli
2) P. aeruginosa
3) C. difficile