biofilms

Question 1

biofilms

Answer 1

cause damage and disease

Question 2

what sort of sieges to biofilmscause

Answer 2

chronic infections on heart valves, implants, dental decay, catheters

Question 3

biofilms act as

Answer 3

reservoirs of contimination/ infection

Question 4

biofilms are difficult to control since

Answer 4

they require a higher dose of antibiotics

Question 5

biofilms are economically costly

Answer 5

e..g NHS costs/ steel pipers under the north sea which are corroded by sulphate reducing bacterial biofilsm

Question 6

cistern 2001

Answer 6

best that 65% of infections may be biofilm related

Question 7

approx 60% of….

Answer 7

HAIs are biofilm related

Question 8

biofilm

Answer 8

“matrix associated microbial populations adherent to each other and or to surfaces ir interfaces” Casterton et al

Question 9

medical infections

Answer 9

implants/ contact lenses

Question 10

domestic

Answer 10

drains/ toilets

Question 11

main infections causes by biofilms in tissues/ fluids are

Answer 11

Bacteremia (blood stream infection). UTIs, pneumonia

Question 12

biofilm microorganisms are

Answer 12

more successful than planktonic

Question 13

advantages of biofilms include

Answer 13

• increased resistance to antimicrobial agents
• increased resistance to host defences e.g TB, intracellular salmonella, reduced capacity for clearing by phagocytosis)
• enhanced genetic interaction e.g. movement of resistance plasmids

Question 14

when antimicrobials diffuse into the biofilm

Answer 14

reaction hiitions leads to tolerance: sub lethal cones lead to selection for resistance e.g. reaction eiwth EPS, chelation, enzymatic degradation, precipitation, volatilisation as alkylated metal compounds.

Question 15

uninhibited diffusion of antimicrobials

Answer 15

tolerance by slow growth e.g. VBNC and persisters. transfer of resistance genes- due to all being in close proximity.

Question 16

biofilms are destroyed using

Answer 16

biocides

Question 17

which microflora was the first to be studied

Answer 17

the mouth

Question 18

over…. species have been identified in the oral cavity

Answer 18

700

Question 19

toothpaste and fluoride the fluoride in it

Answer 19

is used to control biofilm formation

Question 20

why is oral health so important

Answer 20

infections in the mouth can pass through the blood system and cause infection in organs

Question 21

how do plaques form

Answer 21

1) primar colonisers- on the surfaces of teeth and soft tissues
2) secondary colonisers- attach to primary colonisers
3) mutation of plaque- growth in situ and attachment and detachment to the existing biofilm
4) disease causation-pathogenic effect include release of toxins/acids

Question 22

which biofilm causes disease

Answer 22

the mature bioilms

Question 23

three main groups of plaque bacteria

Answer 23

aerobes, facultative anaerobes and obligate anaerobes

Question 24

aerobes

Answer 24

high proportion of young plaque. usually does not cause harm e.g. Neisseria subflaa

Question 25

facultative naerobes

Answer 25

these are the majority of microbes in the mouth. able to survive and grow with high/ low oxygen concentration- usually gram positive e.g. Streptococcus mutants - usually gram neg

Question 26

obligate anaerobes

Answer 26

high number in mature plaque- O2 is toxic or inhibitory to grothw. some of these species are harmful and associated with gum disease e.g.fusobacterium nucleotum

Question 27

example of an aerobe

Answer 27

Neisseria subflave

Question 28

example of a facultative anaerobe

Answer 28

Streptococcus mutans

Question 29

example of an obligate anaerobe

Answer 29

Fusobacterium nucelotum.

Question 30

examples of surfaces in healthcaree where pathogens survive

Answer 30

instruments, bed line, the floor

Question 31

which pathogens survive well on healthcare surfaces

Answer 31

MRSA, salmonella, entrococci, Pseudomons aeruginosa, E.coli, Fusarium

Question 32

% of UTIs caused by biofilms

Answer 32

95

Question 33

% of bateremia cases

Answer 33

87%

Question 34

86$ of pneumonia cases are

Answer 34

ventilator associated

Question 35

prophylaxis

Answer 35

treatment to prevent disease

Question 36

example of public prophylaxis

Answer 36

fluoride use in water- no consent, but very effective in reducing dental decay. only medical treatment give passively without consent

Question 37

mode of action of fluoride

Answer 37

reduction in enzyme activity reduces acid production from carbohydrates. pathogens are outcompeted

Question 38

biofilms cells in comparison to planktonic cells are generally much more

Answer 38

resistant to antibiotics and biocides

Question 39

urinary catheters

Answer 39

quickly acquire organisms on the surge- 5-10% colonisation within 7 days (MRS may achieve a depth up to 5-6 ells in 2h) e.g. proteus spp

Question 40

orthopaedic devices

Answer 40

external fixation from open fractures are out likely to be colonised. Often penetration of antibiotics into biofilms on stainless steel may fail to eradicate the infection

Question 41

prosthetic joint infections

Answer 41

sometimes impossible to cure using antibiotics alone- this may lead to more surgery of even amputations.

Question 42

basic stages of biofilm formation

Answer 42

attachment, growth ,detachment

Question 43

attachment

Answer 43

free floating or planktonic bacteria encounter a submerged surface and within minutes become attached

Question 44

Growth

Answer 44

Extracellular polymeric structure (EPS) production allows the emerging biofilm community to develop a complex, three dimensional structure

Question 45

detachment

Answer 45

biofilms can propagate through detachment of small or large clumps of cells, or by a type of 'seeding dispersal' that releases individuals cells

Question 46

biofilms can move in numerous ways

Answer 46

collectively by rippling or rolling across the surface, or by detachingin clubs or individuals by swarming and seeding

Question 47

emergent properties fo biofilms and habitat formation

Answer 47

1) localised gradients- provide habitat diversity 2) sorption- resource capture 3) enzyme retention-external digestion system 4) cooperation- synergistic micro-consortia 5) competition- continous regeeration 6) tolerance and resistance- biofilm as a fortress

Question 48

localised gradients

Answer 48

provide habitat diversity i.e. different bacteria will survive better at diff oxygen cones/ nutrients conc

Question 49

a key resource of biofilms

Answer 49

calcium

Question 50

cooperation

Answer 50

due to there being a variety of different bacteria which have different biochemical abilities, bacteria are able to use each others products to benefit themselves

Question 51

competition

Answer 51

keeps all bacteria active

Question 52

copiotrophs

Answer 52

an organism found in environments rich in nutrients particularly carbon. tend to grow iim high organise substrate conditions

Question 53

oligotrophs

Answer 53

organisms that live in environments that offer very low levels of nutrients. characterised by slow growth, low rates of metabolism and generally low population density

Question 54

copiotrophic biofilm

Answer 54

creates an oxygen gradient, producing niches for aerobes, fermenters and anaerobes

Question 55

oligotrophic biofilm

Answer 55

nutrient gradients- some cell are more metabolically active, are starving, formation, VNBC, persister and dead cells.

Question 56

communication

Answer 56

chemic and electrical communication

Question 57

cooperation

Answer 57

nitrification- some cells are ammonia oxidisers and other nitrite oxidizers- syngerisist

Question 58

competition

Answer 58

antibiotic, bacteriocins, killer vesicles, biosurfactants, inhibition of quorum sensing, nutrient depletion, cheating