Bacterial Pathogenesis

Question 1

Which type of horizontal gene transfer involves the bacterial taking up environmental DNA?

Answer 1

Bacterial transformation

*Shown by Griffiths experiment with mice and s. pneumoniae

Question 2

Cells that are able to take up DNA are said to be?

Answer 2

Competent

*most frequently take up DNA from same genus

Question 3

Which horizontal gene transfer type is phage mediated?

Answer 3

Bacterial transduction

Question 4

Which horizontal gene transfer type involves pili to transfer genetic information?

Answer 4

Conjugation (bacterial sex)

Question 5

DNA elements that move from one place to another and can disrupt genes or carry virulence/antiobiotic genes are called what?

Answer 5

Transposons (Jumping genes)

Question 6

Differing in G/C content, what virulence genes come in a distinct compact region and commonly carry many types of toxins

Answer 6

Pathogenicity Islands

Question 7

What are the two types of bacterial adherence mechanisms?

Answer 7

1-Pili-dependent adhesion

2-Pili-independent adhesion (surface structure interacts with host receptor)

Question 8

Bacteria residing in extracellular space posses what to survive?

Answer 8

Factors that allow them to prevent uptake and destruction by phagocytes. Varying antigenic surface and secretions that modify host

Question 9

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

Answer 9

Enzymatic activity, Binding

Question 10

what are ways that bacterial pathogens have mastered survival WITHIN a host?

Answer 10

resistant to ROS (reactive oxygen species)
neutralize phagolysosome contents
prevention of phagolysosome fusion
escape from the phagosome

Question 11

What are some factors that facilitate bacterial infection and survival within a host?

Answer 11

the ability to outcompete comensals at many stages
attachment to host cells and tissues
evasion of immune responses
acquisition of limiting nutrients (siderophores for Iron)
spread throughout host and to new hosts

Question 12

How do bacteria evade host defenses? 2 ways

Answer 12

possess virulence factors that prevent uptake and destruction by phagocytes
can survive within a host cell

Question 13

how do bacteria survive extracellular environments? 3 ways

Answer 13

production of capsules that prevent phagocytosis
vary surface antigens to not be recognized by immune response (phase shifting)
secretion of molecules that interfere with host defenses like toxins

Question 14

what are toxins when it comes to bacteria?

Answer 14

they are virulence factors (excreted or not) that are toxic to human/animal/plant cells