biofilm report.pptx

7/31/2019 biofilm report.pptx

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CHARACTERISTICS OF THE ENVIRONMENT


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organized microbial systems

consisting of layers of microbial cells

irreversibly associated with a surface

enclosed in a matrix of primarily polysaccharidematerial (EPS -extracellular polymericsubstances)


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mineral crystals, corrosion particles, clay or siltparticles, or blood may also be found in thebiofilm matrix

Develop in all kinds of surfaces where there ismoisture and nutrients

form on a wide variety of surfaces Inorganic

livingmaterials dead materials

organic remains.


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Inertsurfaces Community water system pipes

Sulfide tailings and acid minedrainage system

Industrial waste treatmentmachines

Contact Lenses


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Living cell surfaces Ruminant digestive tract

Biliary system

Urinary tract

Teeth

Root nodules of legumes


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Heterogeneous structure which includes: cell clusters

void spaces

water channels

end slime streamers


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Surface conditioning

Adhesion of pioneer bacteria

Slime formation

Secondary colonizer Fully functioning biofilm


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SURFACE CONDITIONING

adherence to the surface

neutralization ofsurfacecharge


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ADHESION OF PIONEERBACTERIA Attachment of Planktonic

(free-floating) by electrostatic

attraction and physical forces Some of these cells will

permanently adhere to thesurface with their extracellular

organic matrix.


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SLIME FORMATION Extracellular polymers consisting of

charged and neutral polysaccharidegroups cement the cell and act as anion exchange system for trapping

and concentrating tracenutrients

Accumulation of nutrients promotesreproduction of pioneer cells. The

daughter cells then produce theirown exopolymers, greatlyincreasing the volume of ionexchange surface.


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SECONDARYCOLONIZERS

The exopolymer web snaresother types of microbial cellsthrough physical restraint and

electrostatic interaction. Thesesecondary colonizersmetabolize wastes from theprimary colonizers as well as

produce their own waste whichother cells then use


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FULLY FUNCTIONING

BIOFILM A complex,

metabolically cooperativecommunity made up of

different species each livingin a customized microniche

The mixed species work

cooperatively to carry outcomplex tasks whichotherwise cannot beperformed by a single species


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Microbial Defense resist phagocytosis

Resist penetration of antibiotics

Allow cells to remain in favorable condition

Allow cells to live in close association with each other

Typical way bacterial cells grow in nature


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FACTORS AFFECTING GROWTH ANDACTIVITY OF MICROORGANISMS


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Temperature

Aerobic/anaerobic conditions

pH

Dynamic conditions


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(Tortora et. al, 2010)


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ORGANISMS PRESENT


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Gram negative, rod-shaped

bacterium

Opportunistic human

pathogen Notorious biofilm former

Contact lenses (keratitis)

Endotracheal tube(pnuemonia)

Urinary catheters(bacteriuria)


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Gram positive coccus bacterium

Intravascular catheter (endocartitis)

Endotrachael tube (pneumonia)


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gram positive

Commonly found in oral cavity

Require a nondesquamating (nonepithelial)

surface in order to colonize


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Gram negative pathogen bacterium

Common in water pipes and air condition

Cause Legionellosis or Legionaires disease


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Can form biofilms onglass surface andhuman cells

Gram negative coccibacteria

pathogenic

FIG. 2. Panel A shows a hematoxylin- and eosin-stained section of gonococcal strain 1291 4-day biofilm embedded in OCT andsectioned on a cryomicrotome. This panel shows organisms (dark blue) surrounded by a staining pink matrix. Panels B, C, andD show C-FESEM images of a 3-day biofilm at different magnifications. Panel B, taken at a magnification of x1,000, shows abroad view of the surface. Arrows point to an overlying membrane covering the biofilm. Panel C (magnification, x10,000)shows evidence of organisms embedded within membranous structures that appear to contain a matrix. Panel D(magnification, x20,000) demonstrates typical membranous structures seen crossing the biofilm.


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Gram negative

Straight or curve rods

Pathogenic

water supply resistant to protozoan

grazing


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Gram negative rod-shaped bacteria

Pathogenic

Normal flora of the gut Urinary

catheters(bacteriuria)


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Yeast commonlyfound in human

intestine Catheters

contact lenses


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Common indoor and outdoor mold

lungs

http://www.pasteur.fr/icono/RAR/RAR2007/Aspergillus.jpg


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Soil fungi Can cause lung and brain infections

Can infect brain and lungs


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Chaetophora, Coloechaete scutata, Choleochaetesoluta, Aphanochaete, Gloeotaenium, Oedogonium,Oocystis, Oscillatoria, Phormidium, Chroococcus,Aphanothece, Fragillaria, Cocconeis, Navicula, and

Cymbella

surface of polyethylene (plastics)


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ADAPTATION


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Being ATTACHED rather than SUSPENDEDmakes a WORLD of difference

Microbial cells growing in a biofilmare physiologically distinct from planktonic cells ofthe same organism.


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Microbial cells in biofilm undergoa phenotypic shift in behavior in which large suitesof genes are differentially regulated (they turn on a

whole different set of genes).

Biofilm behavior is much more complex becausethey live in organized communities.


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some of the adaptations and changes observed in abiofilm:

Enhanced Survival Mechanisms Quorum Sensing

Biofilm Matrix Degrading Enzymes

Enhanced Lateral Gene Transfer


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microorganisms excrete a slimy material calledExtracellular Polymeric Substances (EPS)

function: protects the cells within it against:

attack by host defenses e.g. phagocytic cells

much more resistant to biocides and antimicrobial agents

facilitates communication (chemical & physical signals)


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intercellular communication using chemicalsignals.

In biofilms, the matrix material that holds cells inclose proximity allows concentrations of signal

molecules to build up in sufficient quantity toeffect changes in cellular behavior.

Bacterial populations will activate some genes onlywhen they are able to sense, via cell signaling, that

their population is numerous enough to make itadvantageous and/or "safe" to initiate that geneticactivity.


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reasons for communication:

to respond to local cell density

regulates secretion of EPS

synchronize the expression of specialized gene systems


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common classes of signaling molecules: Oligopeptides- Gram-positive bacteria

N-Acyl Homoserine Lactones (AHL)- Gram-negativebacteria

Autoinducer-2 (AI-2)- Gram-negative and Gram-positivebacteria

examples of microorganisms exhibiting quorumsensing: E. coli, P. aeruginosa, V. fischeri and S. enterica


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production of enzymes that degrade biofilmextracellular matrix

e.g. dispersin B & deoxyribonuclease

play role in biofilm dispersal


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cells on the surface of the biofilm are differentfrom the cells within the biofilm matrix

Surface cells no matter how old the biofilm is, are likely to mimic surface

cells of young biofilms (metabolically active and large)

divide and increase the thickness of the biofilm

Embedded cells smaller and grow slower (little oxygen is available)

exist in a somewhat dormant state

becomes active when cells in the outer layers are killed

behavior can change as the thickness of the biofilm changes


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Mold biofilms can physically puncture blood vessels andintestinal walls and allow molds, bacteria and toxins to enter thebody.

Mold biofilms can produce large quantities of alcohol (beveragealcohol), toxic chemicals like acetaldehyde, and a wide range oftoxic chemicals called mycotoxins.

Mold biofilms can produce mold spores which then spread moldinfection to the rest of the body.

Mold biofilms can reduce growth of beneficial probioticbacteria like Lactobacillus and Bifidobacterium.

Many mold biofilms are much more resistant to anti-fungal

drugs than are free living biofilms. It is estimated that 65 to 80%of all mold and bacterial infections involve spreading facilitatedby biofilms.

biofilm report.pptx

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