Week 5: Virulence and Vibrio 2 - Vibrio and biofilms

Question 1

What will we look at here?

Answer 1

other virulence factors

Question 2

Name some other virulence factors of Gram-negative bacteria?

Answer 2

flagellar motility
GbpA
Mucinase
proteases
RTX and VCC cytolysin toxins
OmpU

Question 3

What is the benefit if flagellar motility and virulence?

Answer 3

allows the cells to move towards mucosal surface and penetrate mucus layer

Question 4

What is GbpA?

Answer 4

N-acetyl-glucosamine binding protein

Question 5

What is the role of GpbA?

Answer 5

facilities attachment to chitinous surfaces in the environment and mucin (glycoproteins) in the intestinal epithelium

Question 6

What is mucin?

Answer 6

glycoprotein

Question 7

What is the mucinase complex?

Answer 7

Hap protease and a sialidase

Question 8

What is the role of the mucinase complex?

Answer 8

lead to degradation of the mucus layer.

This reveals the GM1 ganglioside receptor of cholera toxin to bind and enter the epithelial cells.

Question 9

what can bacterial proteases also disrupt?

Answer 9

may also disrupt tight junctions between epithelial cells → impair barrier function; Hap cleaves CT A1 and A2 subunits
(examples of degradation of host structures/tissue)

Question 10

GbpA facilities the binding to what surfaces?

Answer 10

chitinous surfaces

Question 11

What is the role of the Hap protease?

Answer 11

can cleave cholera toxin A1 and B subunits

Question 12

What type f toxins are the RTX and VCC?

Answer 12

cytolysin

Question 13

What is the virulence effect of RTX and VCC?

Answer 13

VCC cytolysin toxins (crosslink actin and form pores in host cells)

Question 14

What is the role of OmpU?

Answer 14

OmpU facilitates resistance to bile and antibacterial peptides

Question 15

What is important for the persistence of Gram-negative bacteria in aquatic environments?

Answer 15

ability to form biofilms

Question 16

What does the formation of biofilms allow?

Answer 16

Ability to form biofilms is critical to persistence in the aquatic environment and also plays a role in the host

Question 17

What are biofilms?

Answer 17

aggregated community of bacterial cells attached to a surface and encased by a protective, self-produced extracellular matrix.

Question 18

What is the purpose of a biofilm/what do they allow?

Answer 18

Biofilms allow strong adherence to a surface and provide protection from extracellular stresses

play a key role within the host

Question 19

In the environment where do biofilms form?

Answer 19

on chitinous (chitin containing) surfaces including zooplankton

Question 20

What can V. cholerae use chitin for?

Answer 20

Vibrio cholerae can use chitin as a sole carbon source and also as an inducer of competence

Question 21

What does binding to chitinous surfaces rely on from the bacteria?

Answer 21

Flagellar motility and MSHA pilus-mediated attachment facilitate surface attachment

Question 22

What facilitates the binding of Vibrio to the surface?

Answer 22

MSHA pilus-mediated attachment facilitate surface attachment

Question 23

What is included in the macrocolonies and mature biofilms?

Answer 23

Macrocolonies and mature biofilm form within a self-produced extracellular matrix comprising Vibrio polysaccharide (VPS) and matrix proteins (RbmA, Bap1, RbmC)

Question 24

What extracellular matric proteins are in the mature biofilm?

Answer 24

RbmA, Bap1, RbmC

Question 25

What can biofilm formation in the host aid?

Answer 25

Biofilm formation in the host may aid attachment to host tissue and resisting shear forces.

Question 26

What is an example of a shear forces?

Answer 26

flow through the GI tract

Question 27

What happens to biofilms later in infection?

Answer 27

Biofilm dispersal promotes release back to the environment (e.g. Hap protease degrades GbpA)

GbpA is the attachment protein

Question 28

What does Hap protease degrade in late infection?

Answer 28

GbpA

Question 29

Why is biofilm dispersal important?

Answer 29

Biofilms shed in stool contain high doses of bacteria and hyperinfective cells → key role in transmission.

Question 30

How can you reduce cholera in water, reduced aggregation of vibrio?

Answer 30

Simple filtration of drinking water → reduced cholera

Question 31

Do aggregated bacteria play a key role in transmission?

Answer 31

YES