Bacterial Pathogenesis Flashcards
Which type of horizontal gene transfer involves the bacterial taking up environmental DNA?
Bacterial transformation
*Shown by Griffiths experiment with mice and s. pneumoniae
Cells that are able to take up DNA are said to be?
Competent
*most frequently take up DNA from same genus
Which horizontal gene transfer type is phage mediated?
Bacterial transduction
Which horizontal gene transfer type involves pili to transfer genetic information?
Conjugation (bacterial sex)
What are the 4 plasmid types?
1-Fertility plasmid (contains tra gene to express pili)
2-Col plasmid (code for bacteriocins that can kill other bacteria)
3-Virulence plasmid (codes for virulence factors)
4-Resistance plasmid (codes for resistance against poisons or antibiotics)
DNA elements that move from one place to another and can disrupt genes or carry virulence/antiobiotic genes are called what?
Transposons (Jumping genes)
Differing in G/C content, what virulence genes come in a distinct compact region?
Pathogenicity Islands
The mechanism used by some bacteria to inject toxins and other proteins into cells through molecular syringes are called what?
Type III secretion Systems (T3SS)
What are the two types of bacterial adherence mechanisms?
1-Pili-dependent adhesion
2-Pili-independent adhesion (surface structure interacts with host receptor)
Bacteria residing in extracellular space posses what to survive?
Factors that allow them to prevent uptake and destruction by phagocytes. Varying antigenic surface and secretions that modify host
What are some ways bacteria have adapted to survive inside the host cell?
- Resist Reactive oxygen species and NO
- Neutralize/prevent phagolysosome
Listeria monocytogenes (G+) uses what cell structure to move around?
Actin tail forms to move it around and spread cell to cell
What are 3 ways that bacteria have evaded amino acid starvation?
1-Transform to dormant state (C. Trachomatis(G-))
2-Make their own AA (M. Tuberculosis(AFB))
3-Degrade proteins and transport free AA in (L. Pneumophila(G-))
What are the 3 types of virulence factors?
- Type 1: Bind and act at host cell surface (Super antigens)
- Type 2: Act on host cell membrane (Pore forming toxins)
- Type 3: A-B type toxins, include single chain (DT) and multisubunit toxins (cholera/anthrax)
LPS (Toll-like mechanism) and Trachial cytotoxin (TCT) (Arrests ciliary movement) are both examples of what?
Non-protein endotoxins
Encoded on a large plasmid, what toxin causes apoptosis/necrosis resulting in Buruli ulcers?
Mycobacterium ulcerans polyketide-derived mycolactone
What class of toxin binds class II MHC to TCR and exhausts the T cell eventually killing it?
Superantigens
Which bacteria is commonly found in the nasal cavity, causes food poisoning, toxic shock, and abscesses?
Staphylococcus Aureus (G+)
How are many of the virulence factors encoded by S. Aureus regulated?
Quorum sensing (Auto inducers produced by the bacteria help them know how many more of themselves are near by)
What are two membrane-disrupting toxins?
Phospholipases and Pore-forming toxins
In A/B toxins the A subunit is responsible for ________ and the B subunit mediates _________ to a receptor and transferring the A subunit across the membrane
Enzymatic activity, Binding
What toxin causes mucosal cells to pump large amounts of Cl- out resulting in diarrhea, loss of electrolytes and dehydration?
Cholera toxin
A formation of a pseudomembrane in the throat and lungs is caused by what?
Diptheria Toxin
*enters via Heparin binding epidermal growth factor like receptor
A non-toxic version of a toxin used as a vaccine is called what?
Toxoid
