Microbial methods Flashcards
3 features of the epidermis that lead to it being a good barrier to infection?
mechanical barrier, low pH, production of antimicrobial fatty acids/defensis
antimicrobial defensins are produced by which cell types?
epithelial cells in skin and mucosa
microbes “changing their coats” to evade immune cell recognition is called what?
antigenic variation
Does genetic rearrangement or genetic reassortment lead to antigenic shift?
reassortment leads to antigenic SHIFT, rearrangement (e.g. recombination, gene conversion, site-specific inversion) leads to antigenic drift
Protein A produced by S. aureus helps the organism do what?
evade phaocytosis by competitively binding to Fc portion of antibodies
chronic viral infections can lead to “t-cell exhaustion,” in part due to increased expression of which surface protein?
PD-1
a bacterial trait that allos them to turn on gene expression and express specific traits only when the organism grows to a high concentration is called what?
Quorum sensing
which receptor does lipoteichoic acid bind to?
TLR-2
bacterial toxins that stimulate a high number of T lymphocytes leading to massive T cell prolifeartion and potentially SIRS are called what?
superantigens
What are the 5 main types of functions provided two the infectious agent by virulence factors?
- Colonize (adhesins ) 2. Invade (invasins) 3. evade 4. suppress 5. acquire (siderophores)
Which cell in the GIT is not covered by mucus?
M-cells in Peyer’s patches
where in the GIT would you encounter follicle associated epithelium (FAE?)
Peyer’s patches
centrifugal turbulance is a physical barrier encountered in which portal of entry?
Respiratory
which three cell types are most often involved in “leukocyte trafficking” by infectious agents?
Macrophages/monocytes, lymphocytes, dendritic cells
what is the most common type of cell used as a target for microbes?
epithelial cells
what is the primary target of colonization and replication for Swine dysentery (B. hyodysenteriae)?
goblet cells of the colon and cecum
mucus is a strong chemoattractant for which types of bacteria?
spirochetes
what is the primary target of colonization for Mycoplasma hyopneumoniae, the causitive agent of porcine enzootic pneumonia?
Cilia
Which bacterial agent colonizes ciliated respiratory epithelial cells and uses neuraminidase to injure and destroy respiratory cilia?
Manheimia hemolytica
By which mechanism does lawsonia intracellularis enter the cells of the intestinal crypts?
endocytosis (phagocytosis) - escapes before phagosome-lysosome fusion occurs
which virus of pigs crosses the mucosal barrier by using M-cells?
Porcine circovirus type II - PMWS
receptor mediated endocytosis generally occurs on which cell surface? what about exocytosis?
endocytosis occurs on the apical surface, exocytosis occurs on the basolateral surface
which virulence factor does Leptospira use to penetrate endothelial cells and vascular walls?
invasive motility
parvovirus uses receptors expressed only on which cell surface to gain entry?
basolateral