probiotics and biofilms

Probiotics and biofilms TW 1

Probiotics and

BiofilmsBy : Tewdros Tesfa (BSc., MSc.) Haramaya University Wondmagegn Demsiss (BSc., MSc.) Wollo University

Probiotics and biofilms TW

2

Outline

ProbioticsMechanism of action of probioticsIntroduction About biofilmFormation, development and dispersal of

biofilmsProperties of biofilms and Quorum sensingUses and problems of biofilmsBiofilms and infectious diseasesControl and removal of biofilms


3

Objectives

At the end of this presentation you will be able to:Define biofilms and ProbioticsUnderstand the mechanism of action of ProbioticsDescribe how biofilms are formed. State the role of biofilms in infectious disease.Understand the antimicrobial drug resistance

mechanisms of biofilms.Know the prevention and control mechanism of

biofilms.


4

Definition

Live microorganisms which when administered in adequate amounts confer a health benefit on the host” (FAO/WHO, 2002)

Are live microorganisms; could be fungi or bacteria

Food ingredientsHave beneficial health effectse.g. Lactobacillus, Bifidobacterium,

Saccharomyces boulardii (yeast)


5

Definition

Prebiotics- dietary substances (non digestible by human enzymes, non starch carbohydrates) e.g. inulin, lactulose, oligofructose Stimulate favorable growth or

activity of probiotic bacteria

Synbiotics (eubiotics)- Products that contain both probiotics and Prebiotics


6

Mechanism of action

Anti cancer effects Are shown to reduce concentration of carcinogenic chemicals (Scavenge superoxide radicals)

Modify epithelial cell kinetics


7

Mechanism of action

Anti diarrheal effect Lowering GI pHSecreting bacteriocinsReconstruction of normal flora (especially antibiotics associated and radiation induced diarrhea)

Competing for adhesion sites


8

Mechanism of action

Immunomodulation Enhanced barrier

Increased mucus secretion Epithelial membrane integrity

Activation Bacterial surface antigens

Suppression Inducing T-reg cells Inducing regulatory cytokines; TGF-β, IL-10 Counteract pro-inflammatory cytokines


9

Mechanism of action

Anti-allergy effectsReducing antigenic challenge; by

enhanced membrane integrity ( as most allergic reactions are thought as a result of large antigenic insult after barrier disintegrates)

Modification of allergen receptor


10

Mechanism of action

Stomach and Urogenital health

Inhibitory effect of lactic acid for

H.pylori

An estimated reason for Urogenital

health is maintenance of acidic

environment (lactic acid) and

production of other antibacterial

chemicals (e.g. H2O2)


11

Other roles of Probiotics

Reduction of hypertension- by fermentation end products which have inhibitory effect on angiotensin I conversion

Lowering blood cholesterol levelImprovement in Ca absorption Production of some vitamins and

digestive enzymes


12

Questions to be answered

Dose of the probiotic bacteria For how long should it be takenCorrelation of specific probiotic

species with its specific action and target


13

Summary


14

Introduction

What are biofilms?Why should we care about biofilms?What makes them special?What happens as a result of biofilms?How they are formed?How they are removed?


15

Introduction about biofilms

The concept of bacterial biofilm was proposed in 1936.

In natural aquatic environments bacteria are predominantly not free floating but grow as multi-species communities attached to submerged surfaces.

Over 90% of all bacteria live in biofilms. In clinical medicine, many environments

provide optimal conditions for the formation of bacterial biofilm, such as contact lenses, urinary catheters, and so on.


16

Introduction

What is Biofilm??A biofilm is a community of micro-

organisms, attached to a wet or moist surface. Microorganisms include bacteria, yeasts, algae, fungi.

These microbes make a sticky, slimy, gel-like substance and surround themselves with it.

http://www.biology-online.org/dictionary/Bacteria

http://www.biology-online.org/dictionary/Yeast

http://www.biology-online.org/dictionary/Algae

http://www.biology-online.org/dictionary/Fungi


17

Bio film constitutes

A biofilm is an aggregate of microorganisms in which

cells are stuck to each other and/or to a surface.

These adherent cells are frequently embedded within a self-

produced matrix known as extracellular polymeric

substance (EPS).

Biofilm EPS, which is also referred to as "slime," is a

polymeric jumble of DNA, proteins and polysaccharides.


18

Bio film constitutes

Biofilms may form on living or non-living surfaces

and can be prevalent in natural, industrial and

hospital settings.

For example, a pebble in a pond is covered in slimy

green stuff. That slime is a biofilm.

The slippery layer that builds up inside a waste

pipe is a biofilm.

The plaque that builds up between the gum and

the tooth is a biofilm.


19

Why Do Bacteria Make Biofilms?

Biofilms protect the pathogenic bacteria, making them hard to kill.

Hiding in biofilms, bacteria can spread throughout the body.

Large, sticky biofilms resist the attack of the immune system and antibiotics.


20

Formation and Development of Biofilms

• Biofilm formation is not a random process

Biofilms start as just a few bugs forming a thin layer.

They can develop into complex, three dimensional structures housing millions of individual bacterium.

Like miniature cities, they have towers, columns, bridges and channels for the flow of nutrients.


21


What is the use of understanding the….?

formation, composition, and characteristics of the biofilm assists in

its control and for developing treatment strategies of biofilm diseases.

The greater our understanding of the processes involved in biofilm formation, the greater the chance of developing remedies.


22


The pattern of biofilm formation can be divided into three phases:

I. Attachment of bacteria to a solid surface;

II. Formation of micro colonies on the surface; and

III.Formation of the mature biofilms


23


Neighbors in the biofilm work together to build their niche environment.

Some bugs use their bodies to build support structures, arches, columns.

Others form the foundation and are good at sticking onto the host surface.

Some make the sticky goo or slime that protects them.


24


Formation of a biofilm begins with the attachment of free-floating microorganisms to a solid surface.

These first colonists adhere to the surface initially through weak, reversible adhesion via van der Waals forces.

If the colonists are not immediately separated from the surface, they can anchor themselves more permanently using cell adhesion structures such as pili.


25


Once a bacterium attaches to a surface, it activates a whole different set of genes that gives the bacterium different characteristics from those that it had as a free-floating organism.

The first colonists facilitate the arrival of other cells by providing more diverse adhesion sites and beginning to build the matrix that holds the biofilm together.

Some species are not able to attach to a surface on their own but are often able to anchor themselves to the matrix or directly to earlier colonists.

It is during this colonization that the cells are able to communicate via quorum sensing.

http://en.wikipedia.org/wiki/Quorum_sensing


26


Once colonization has begun, the biofilm grows through a combination of cell division and recruitment of new bacteria.

Biofilm doubling times are rapid in early development and slower in more mature biofilms.

A second wave of bacterial colonizers adheres to bacteria that are already attached to the surface.


27


The bacteria cluster together to form sessile, mushroom-shaped micro colonies that are attached to the surface at a narrow base.

Co aggregation is the ability of new bacterial colonizers to adhere to the attached cells.

The result of co aggregation is the formation of a complex array of different bacteria linked to one another. This is what we call it mature biofilm

Their Own Little World!!!!


28


Microbes form a biofilm in response to many factors, which may include

cellular recognition of specific or non-specific attachment sites on a surface,

nutritional cues, or in some cases, by exposure of

planktonic cells to sub-inhibitory concentrations of antibiotics.


29

Dispersal of biofilms

Dispersal of cells (bacteria) from the biofilm colony is an essential stage of the biofilm life cycle.

Dispersal enables biofilms to spread and colonize new surfaces.

Enzymes that degrade the biofilm extracellular matrix, such as dispersin B and deoxyribonuclease, may play a role in biofilm dispersal.

Probiotics and biofilms TW 30


31

Quorum sensing

To work together efficiently, the bugs need to talk to one another. They do so by chemical signals. Bacteria produce diffusible extracellular signalling molecules ( AHLs and oligopeptides)

Bacteria are often considered as simple unicellular organisms, but research has recently shown that many bacteria possess ability to communicate with one another and to organize to communal groups.

to monitor their own population density and to coordinate expression of specific sets of genes in response to the cell density.

This type of cell-density-dependent gene regulation is termed Quorum sensing.

http://www.cambridge.org/catalogue/catalogue.asp?isbn=0521846382


32

Properties and structure of biofilms

Biofilms are surface-attached microbial communities with characteristic architecture and phenotypic and biochemical properties distinct from their planktonic counterparts.

One of the best-known of these biofilm specific properties is the development of antibiotic resistance

Biofilms are characterized by • structural heterogeneity, genetic diversity,

complex community interactions, and an extracellular matrix of polymeric substances.


33

Properties cont…

The structure of a biofilm community comprises bacterial

A. Micro colonies,B. An extracellular slime layer, C. Fluid channels, and D. A primitive communication system.


34

Properties cont…

A. Each micro colony is a tiny, independent community containing thousands of compatible bacteria.

Bacteria in the center --strict anaerobic environment, while other bacteria at the edges -aerobic environment.

Thus, the biofilm structure provides a range of customized living environments (with differing PHs, nutrient availability, and oxygen concentrations) within which bacteria with different physiological needs can survive.

B. The extracellular slime layer is a protective barrier that surrounds the mushroom shaped bacterial micro-colonies.


35

Properties cont…

The slime layer protects the bacterial micro colonies from antibiotics, antimicrobials, and host defense mechanisms.

C. A series of fluid channels penetrates the extracellular slime layer.

These fluid channels provide nutrients and oxygen for the bacterial micro colonies and facilitate movement of bacterial metabolites, waste products, and enzymes within the biofilm structure.

D. Each bacterial micro colony uses chemical signals to create a primitive communication system used to communicate with other bacterial micro colonies.


36

Depiction of the dynamic nature of a biofilm community.


37

USE AND PROBLEMS OF BIOFILMS

BenefitsHelp remove pathogens and reduce the amount of organic

matter in the water, and Eliminate petroleum oil from contaminated oceans or

marine systems. ProblemsThey are associated with persistent infections and They are notorious for their pipe-clogging and -

corroding properties, a costly irritation in industrial settings.

Undesirable taste and odor issues in the water industry; Pipe corrosion within oil and gas industries and souring of

oil in pipelines and storage facilities. Can make sanitation difficult in food preparation areas.

http://en.wikipedia.org/wiki/Petroleum


38

Biofilms and infectious diseases

• Biofilms have been found to be involved in a wide variety of microbial infections in the body.

It has taken longer to make a clear connection of biofilms to persistent infections in native tissue.

According to the CDC, 65% of all infections in developed countries are caused by biofilms

Biofilms are produced by most if not all pathogens.


39

Biofilms and cont…

A well known example of a microbial biofilm in human disease is dental plaque, which is the most known and studied biofilm (secreting acids that destroy teeth and gums).

Pseudomonas aeruginosa, causing an incurable infection in cystic fibrosis patients (Singh et al. 2000),

and Staphylococcus aureus and Staphylococcus epidermidis, infecting indwelling devices (Mack et al. 2004), are probably the best-known biofilm-producing organisms.


40


Biofilms are responsible for a significant portion of acute infections.

A classic case is that of Legionnaire’s disease, an acute respiratory infection resulting from aspiration of clumps of Legionella biofilms detached from air and water heating/cooling systems.

Many food borne pathogens such as E. coli 0157:H7, Listeria monocytogenes, Yersinia enterocolitica, Salmonella spp. and Camphylobacter jejuni can form either single-species or multi-species biofilms on food surfaces and equipment


41


Teeth with Dental Caries The term dental caries refers to the destruction, or necrosis, of teeth usually by bacterial action resulting in a condition commonly known as tooth decay. .


42

Examples of diseases associated with biofilmOtitis media (middle ear infections) Periodontal diseaseGingivitisDental CariesChronic bacterial prostatitisEndocarditisSinusitisUTIInfections in cystic fibrosisInfections of all known indwelling devices such as

catheters, orthopedic prostheses, and heart valves;


43

Anti-microbial resistance of Biofilm

Bacteria within biofilms are up to 1000 times more resistant to antimicrobials than the same bacteria in suspension.

Extracellular matrix of the biofilm is a passive barrier for antibiotics

To protect the cells against the antibiotics tobramycin and gentamicin P. aeruginosa produces only in biofilms a periplasmic cyclic glucan which complexes antibiotics turning them into harmless compounds.


44

Anti-microbial resistance cont…

In biofilms up to 20% of all genes are differently expressed.

Bacteria in biofilms grow slower and with the reduced metabolic activity they are less prone against most antibiotics.

Preliminary evidence suggests that different bacteria within a biofilm can trade genes -- possibly including Abx resistance genes

The infections associated with biofilms may appear to respond to systemic antibiotics because planktonic cells respond and symptoms are reduced, but the persistence of adherent cells leads to recurrent episodes of infection.


45

Three hypotheses for mechanisms of antibioticresistance in biofilms


46

Prevention and control of biofilm

An effective mechanical control mechanism is biofilm detachment.

Interfere with the bacterial cell to cell communication

A novel alternative to antibiotics are Probiotics.

A unique spray made from stabilized enzymes that can readily dissolve the biofilms.


47

Conclusion and recommendation

Biofilms, once considered odd curiosity, are now one of the hottest topics in microbiology. Biofilms occur everywhere: dental plaque is one the most common biofilms that decay teeth,

other biofilms can clog water pipes, others can contaminate

almost any medical device inserted into the body, ranging from contact lenses to catheters and artificial hearts.

Microbiologists have traditionally researched only free-floating, individual bacteria growing in laboratory cultures.“Microbiologists have been barking up the wrong tree since the time of Pasteur,” says Costerton.

probiotics and biofilms

Health & Medicine

problems of biofilms

result of biofilms

biofilms tw1

role of biofilms

control mechanism of

probiotics mechanism

probiotics introduction

prebiotics probiotics