Biofilm formation by staphylococci

and streptococci

Guided by,Smt. GayathriAssistant Professor,Dept of Biotechnology and Biochemical Engineering

Menon Lakshmi Rajan,Reg no: 13402018Dept of Biotechnology and Biochemical Engineering

Lets Divide&Rule!

1. Biofilm forming microbes vs planktonic species

2. Staphylococci and Streptococci

3. A biofilm

4. Mechanism of biofilm formation

5. Biofilm in human body

6. Applications

1.Biofilm forming microbes v s

planktonic species

» Nearly every species of microorganism, not only bacteria and archaea, have mechanisms to produce biofilm.

» When a cell switches to the biofilm mode of growth, it undergoes a phenotypic shift in behavior .

» The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism.

» With the course of time, due to the flexibility of the bacterial gene expression, formation of biofilm was endured by the species.

2.Staphylococci

and Streptococci

» commensals and opportunistic pathogens.

» cause a variety of infections in humans and animals.

» Biofilm formation is an important survival strategy adopted by these Gram-positive cocci.

» Biofilm growth allows bacteria to persist in vivo by resisting host immune defenses and antibiotics.

» Established biofilms can tolerate antimicrobial agents at greater concentrations.

Staphylococi pyogenes

Scanning electron micrograph of Staphylococi pyogenes .

Streptococi

Scanning electron micrograph of Drug-resistant Streptococcus pneumoniae

» Staphylococcus frequently colonize the skin and upper respiratory tracts of mammals and birds.

» Causes diseases in humans and animals through either toxin production or penetration.

» many streptococcal species are not pathogenic.

» certain Streptococcus species are responsible for many cases of Conjunctivitis, meningitis, bacterial pneumonia, endocarditis and necrotizing fasciitis.

3.Biofilm

» A biofilm is an assemblage of microbial cells that is irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material.

» Biofilms may form on a wide variety of surfaces.

» Non-cellular materials may also be found in the biofilm matrix.

» Biofilm-associated cells can be differentiated from their suspended counterparts.

four driving forces behind bacterial biofilm formation

Forms as a stress response.

They are resistant to physical forces.

Organisms within biofilms can withstand nutrient deprivation, pH changes, oxygen radicals, disinfectants, and antibiotics.

Biofilms are also resistant to phagocytosis.

As a DEFENCE

biofilm formation as a mechanism to remain in a favorable niche.

The body is an appealing place for bacteria to live.

The body is nutrient rich and relatively stable with respect to water content, oxygen availability, and temperature.

As a part of COLONIZATION14

Division of the metabolic burden:

o mixed biofilms have different requirements and perform different metabolic functions

o the heterogeneity within biofilms results in a ‘‘division of labor’’ of sorts that increases the metabolic efficiency

Selfless behavior:

o bacteria can exhibit altruistic behavior

o unselfish behavior in biofilm inhabitants can increase the overall growth yield

COMMUNITY15

oral streptococci are very highly adapted to sessile growth on the surface of teeth

planktonic growth would cause them to be quickly washed away

These bacteria are likely spend the majority of their natural existence growing as a biofilm

DEFAULT MODE OF GROWTH16

4.Mechanism of

biofilm formation

STEPS IN BIOFILM FORMATION

Attachment

Maturation

Dispersion

ATTACHMENT The solid-liquid interface between a surface and

an aqueous medium (e.g., water, blood) provides an ideal environment for the attachment and growth of microorganisms.

Factors to be considered:

➜ Substratum effects

➜ conditioning films forming on the substratum

➜ hydrodynamics of the aqueous medium

➜ characteristics of the medium

➜ various properties of the cell surface

MATURATION » Biofilm Structure:

o composed primarily of microbial cells and EPS

o EPS may account for 50% to 90% of the total organic carbon of biofilms

o Some of these polysaccharides are neutral, polyanionic or polycationic

» Biofilm architecture:

o heterogeneous both in space and time

o contains microcolonies of bacterial cells encased in an EPS matrix and separated from other microcolonies by interstitial voids

» Biofilm Ecology:

basic structural unit of the biofilm is the microcolony

the cycling of various nutrients within the colonies

Proximity of cells within the microcolony provides an ideal environment for

o exchange of genes: Conjugation occurs at a greater rate between cells

o quorum sensing: bacterial cells communicate with each other by releasing, sensing and responding to small diffusible signal molecules

DISPERSAL

Biofilm cells may be dispersed either by

➜ shedding of daughter cells from actively growing cells

➜ detachment as a result of nutrient levels or quorum sensing

➜ shearing of biofilm aggregates

Stepwise pictorial

representation of biofilm formation

“National Institute of Health estimates that more than 80% of microbial infections in human body are caused by BIOFILM, many of

them causing chronic and reoccuring problems”

DID YOU KNOW ? ?

5.BIOFILM

INHUMAN BODY

Biofilm in mouth

Biofilm in gut

» Infections from biofilm are extremely difficult to treat.

» ability to harbor and protect the organisms within it makes them resistant to most antibiotics.

» Biofilms are great threat to medical implants.

» HOW TO BREAK THROUGH UNHEALTHY BIOFILM?

o by taking Proteolytic enzymes on an empty stomach

o certain food items like Cloves ,Garlic ,Oil of Oregano help in chelating the heavy metals

6.APPLICATION

S

1.BIOREMEDIATION

2.BIOBARRIER

3. WASTE WATER MANAGEMENT

4. BIOREACTORS

LET’S REVIEW AND CONCLUDE

Biofilm formation is an important survival strategy adopted by microbes

Biofilm growth changes bacteria physiologically and phenotypically

Formation mechanism is simple with just 3 steps.

It can cause great health menace but can also be used productively

Impact: the potential to lead to novel approaches to diagnosing and treating biofilm-related infections.

deeper investigation into the basic biology of the diseases.

REFERENC

E

1. Food safety and sanitation-Penn state food science

2. What drives bacteria to produce a biofilm?-Kimberly K. Jefferson (FEMS Microbiology Letters 236 (2004) 163–173)

3. Fundamentals and Applications of Biofilms Bacterial Biofilm Applications-Ching-Tsan Huang

4. Biofilm: importance and application- S Chakaraborty, KR Mahadik,A N Khopade (Indian journal of biotechnology)

5. Biofilms: Microbial Life on Surfaces-Rodney M. Donlan

6. Biofilm formation by staphylococci and streptococci-Pietro Speziale and Joan A. Geoghegan(Front. Cell. Infect. Microbiol., 08 April 2015)

7. Streptococcus pneumoniae biofilm formation and dispersion during colonization and disease-Chao, Y., Marks, L. R., Pettigrew, M. M., and Hakansson(Front. Cell Infect. Microbiol. 4:194.)

Thank You!Any questions?