biofilms

Question 1

biofilm

Answer 1

aggregates of bacterial cells encased in a polymeric matrix 
10-30% bacterial cells
70-90% EPS 
EPS = extracellular polymeric substance
always a polymer
usually exopolysaccharide

Question 2

staphylococci

Answer 2

poly-N-acetylglucosamine

deacetylated - positive - attracts negative cells

Question 3

triggers

Answer 3

environmental stress 
detection by signalling molecules:
N acetyl omoserine lactones 
autoinducers (p auriginosa)
oligopeptides 
prompt changes in gene expression
genes for attachment, EPS
cyclic diguanate second messenger 
800 genes

Question 4

properties

Answer 4

slowed growth
resistant to antibiotics and immune system - transient
matrix interferes with immune response
evolve quicker - true resistance
acceleration of endogeous mutation and horizontal gene transfer
driven by oxidative stress

Question 5

infections involving biofilms

Answer 5

80% infections show biofilm
peridontal diseases - actinomyces, bacteroides, actinobacter
native valve endocarditis - viridans strep
cystic fibrosis - P. aerunginosa

Question 6

oral biofilms

Answer 6

gingivitis
plaque - gum inflammaion
polymicrobial
actinobacteria, strep mutans

Question 7

chronic wounds

Answer 7

60%
prevents healing
polymicrobial
debridement

Question 8

staphylococcal biofilms

Answer 8

S. aureus
S. epidermis
have MSCRAMMS
bind host proteins

Question 9

treating biofilms

Answer 9

calgary biofilm device
96 plates with pegs to evaluate inhibitory molecules
repurposing compounds
redox active agents useful as antioxidants
bronopol and bronidox personal care products have broad spectrum antibiolfilm activity
can be matrix killers or cell killers