Biofilms

Question 1

What is a biofilm?

Answer 1

-morphologically heterogeneous and multi-layered matrices commonly established by sessile bacteria to be able to attach to surfaces and eachother

Question 2

How are biofilms formed naturally?

Answer 2

• offer their member cells benefits

-trapped cells are exposed to toxic by-products and also mass transfer limitations

Question 3

What happened biofilms if the environmental conditions change?

Answer 3

They are threatened,
Under these circumstances bacteria respond by returning to their free living life style allowed them to disperse and re-colonise

Question 4

How are biofilms created in nature?

Answer 4

They are diverse from their formation on teeth as plaques and submerged rocks in a stream

Question 5

Outline the biofilms phenotype characteristics;

Answer 5

•a slower growth rate
•motility
•increased antibiotic resistance
•DNA release
•cellulose
•transport/uptake systems

Question 6

Outline the impact of polysaccharides on biofilms;

Answer 6

They impact on microbial virulence significantly

They determine biofilm architecture by protecting the cells from the body defences and antimicrobials

Bacteria have capsular polysaccharides and exopolysaccarides

Question 7

Why are exopolysaccarides important in biofilms?

Answer 7

Synthesised by bacteria and secreted to the environemnt

Question 8

Outline the key components of the matrix in biofilms;

Answer 8

Matrix consists of;

-living cells
-dead debris
-proteins
-polysaccharides
-lipids

Question 9

Describe the antibiotic resistance within biofilms;

Answer 9

• in the centre of the biofilm the bacteria have greater antibiotic resistance

Question 10

Outline the factors that hyposynthesised to constitute a multi-layered defense:

Answer 10

-poor antibiotic penetration
-slow growth
-nutritient limitation
-adaptive stress responses

Question 11

When do persisted cells occur?

Answer 11

Occur stochastically within a culture as an altruistic mechanism for population survival in the event of an unexpected challenge from antimicrobial agents or other environmental stresses

Question 12

What is the function of persister cells?

Answer 12

• rapid growth and decision
• remain slow growing
• dormant in order to be tolerant of antimicrobials

Question 13

Outline 4 of the components of a basic flow cell reactor system;

Answer 13

1- the nutrient supply
2- an access port
3- the flow cell
4- the waste disposal container

Question 14

Describe what the quorum sensing (QS) is?

Answer 14

A process of bacterial communication mechanisms including releasing, detecting and responding in small hormone-like molecules or diffusable molecules termed “autoinducer”

Question 15

Outline what enterococcus faecalis function is?

Answer 15

enterococcus faecalis is a bacteria found in the intestine

-Has high levels of antibiotic resistance
-Can cause life threatening infections
-anaerobic
-clinical isolates have the ability to form a biofilm in vitro

Question 16

What does the succinic acid from campylobacter species promote?

Answer 16

Promoted the growth of phorphyromanas gingivalis

Question 17

What does fusbacterium species produce?

Answer 17

Both thiamine and isobutyrate that may be used by spirochetes to support their growth

Question 18

How does cystic fibrosis occur?

Answer 18

Mutations in chloride channel in epithelial cells

Question 19

Outline the 1st and 2nd stage of cystic fibrosis;

Answer 19

1st stage = intermittent infections

2nd stage = permanent infections with pseudomonas aeruginosa

Question 20

What are some short term antibiofilm agents?

Answer 20

-lactoferrin
-gallium
-farnasol

Question 21

What are some long term antibiofilm agents?

Answer 21

-quorum sending inhibitor
-autoinducer
-furanones