Biofilm formation involves the accumulation of microorganisms on surfaces where they form sessile communities encased in an extracellular polymeric substance matrix. Biofilm formation progresses through initial attachment, irreversible attachment aided by EPS production, early development, maturation, and dispersion. Virulence factors and quorum sensing play important roles in biofilm formation. Mature biofilms pose challenges for antibiotic treatment and are implicated in various pathogenic conditions like cystic fibrosis, periodontitis, and device-related infections. Therapeutic strategies aim to target biofilm formation, virulence factors, and quorum sensing.

1. BIOFILM FORMATION AND ITS ROLE IN PATHOGENESIS
Presented by : T.Prashanth kumar
Reg no : PC/2021/215
Guide : Dr Nitin Pal Kalia

2. INTRODUCTION
BIOFILM :
It is defined as naturally
accumulation of microorganism on
wide variety of surfaces . where
they form sessile , sedentary
communities. Those surfaces
include medical devices and
industrial pipes. These
accumulation of microorganisms of
mono-or poly-aggregates known as
biofilm.
Image courtesy of Dr Elena Jordan-Lluch, University of Nottingham

3. How do Biofilms Form?
Biofilm formation can be divided into five stage:
1. Initial weak , reversible attachment of cells.
2. Production of EPS , resulting in irreversible attachment.
3. Early development of biofilm architecture.
4. Maturation of biofilm.
5. Dispersion of single cells from the biofilm.
Vasudevan, 2014, J Microbiol Exp 1(3): 00014. DOI:
10.15406/jmen.2014.01.00014

4. What is EPS?
EPS : Extracellular polymeric substance
 Provides protection from antimicrobials , pH shifts, UV radiations ,
osmotic shock etc.
 EPS is able to sequester metal ions , cations and toxins.
 The general composition of bacterial EPS comprises polysaccharides,
protein , nucleic acids, lipids, phoshpolipids , and humic substance.

5. Properties of The Substratum Properties of The Bulk Fluid Properties of Cell
Hydrophobicity Temperature Cell surface hydrophobicity
Conditioning film pH Extracellular appendages
Texture or roughness Velocity and nutrients Extracellular polymeric substances
Factors Involved in Biofilm formation

6. Hydrodynamic conditions:
Hydrodynamic conditions(shear stress , shear force, flow rate , velocity) affects biofilm formation
by changing nutrient and oxygen supply.
These condition also influence density and strength of biofilm
There is considerable evidence that shear stress has effects on the growth rate,EPS Production
and genetic behaviour of biofilm
For example,analysis of P.Putida biofilm maturation under lower shear stress
Quorum-sensing in P.aeruginosa biofilm also influenced by hydrodynamical conditions.
Sourec: Despoina Vokou

7. WHAT IS QUORUM SENSING?
• Quorum sensing is typically thought to mediate intraspecies
communication, there is evidence that interspecies interaction also
occurs.
• Gram positive and Gram negative bacteria use different types of QS
systems that involve the production , detection , and respond to the
extra cellular signalling molecules called autoinducers.
ex : Acyl homoserine lactone
Bacterial metabolites
secreted proteins

8. QS system in Gram positive QS system in Gram nagetive
https://doi.org/10.1007/s12602-019-09555-4
https://www.researchgate.net/profile/V-B-Oti

10. HOW VIRULENCE FACTORS INVOVED IN BIOFILM FORMATION?
• Virulence: Ability to cause pathogenicity.
• Determinants of virulence:
i. Transmissibility
ii. Adhesion
iii. Invasion of host cell by pathogen
iv. Spreading factors
v. Evading host defences

11. • These virulence determinants in Enterococcus spp. are involved in
pathological process and the ability to growth in biofilm
• Virulence factors especially in Enterococcal species which include
enterococcal surface protein(encoded by esp),aggregation
substance(encoded by agg or asa1), and collagen-binding
protein(encoded by ace)
• Production of adhesin-like E. faecalis and E. faecium endocarditis
antigen A(encoded by efaAfs and efaAfm)
• Moreover , expression of pili(encoded by ebpABC , srt , pil) on the cell
surface

12. The c-di-GMP signalling module
• C-di-Gmp is the first secondary messenger which play important role
in biofilm formation
• This molecule is allosteric activator of cellulose synthesis in
Gluconacetobacter xylinus
• Also controls the switch from motile, planktonic lifestyle to sessile,
biofilm associated existence
• Cyclic-di-Gmp also affects other fundamental behaviors , such as cell
cycle proliferation , development, fimbrial synthesis , RNA modulation
and stress response

13. Image from "Principles of c-di-GMP signalling in bacteria" by Regine Hengge.

14. Metabolic changes during Biofilm formation
 In primary metabolites , the levels of TCA intermediates(i .e ,citrates ,
aconitate, succinyl-coenzyme A , succinate , malate) increased(12-16 hr)
 In secondary metabolites, levels of N-acetylated amino acids(e. g., N-
acetyl-glutamine and N-acetyl glutamate) increased(~12hr)
https://journals.asm.org/doi/10.1128/mBio.00623-19#fig2

15. How biofilm form help in escape antibiotic
treatment
Limited
penetrance
Physiological
heterogeneity
Stress
responses
Persister cells
Reduced drug
exposure
Induction of
error-prone
damage repair
pathways
Exchange of
resistance
elements

16. Impact of biofilm in wound healing
Source: Biofilms Made Easy. 2010. Wounds International 1(1).

17. Biofilm role in pathogenesis
A . Cystic fibrosis
(streptococcus aureus)
B . Periodontitis(dental plaque)
https://www.immunology.org/public-information/bitesized-immunology/pathogens-and-
disease/biofilms-and-their-role-in

18. C . Native valve endocarditis
(candida , Aspergillus , streptococcus)
D . Device related infections
Urinary catheters
Orthopedic implants
Prosthetic joints
Endotracheal tubes..etc,.

19. Therapeutic strategies(Anti-biofilm)
• Currently , biofilm formation and quorum sensing are considered as
prospective novel target for antimicrobial therapy to control
multidrug-resistant infections.

20. • Use of enzmes : A mixture of enzymes may be necessary for biofilm
degradation
Exmples : Deoxyribonuclease I, glycoside hydrolase (dispersin B)
• Novel antibiofilm agent : Docosanol (fatty alcohol) from streptomyces
• Which target the virulence factors of MRSA(methicillin-resistant
staphylococcus aureus)
• This molecule also enhanced the neutrophil-mediated killing by
interfering with haemolysin production

21. • Use of photoactive dye(capable of chemical or physical changes in
response to illumination)
• Photodynamic theraphy (PDT) has potential application in prevention
of wound biofilm infections
• Prontosan (betaine+polyhexanide) :A real knockout in wound cleaning
• Alteration of membrane polymerization
ex:Lantibiotics (nisin , gallidermin)
chlorhexidine
Polyhexamethylene biguanide

22. Clinical status of drugs
Condition or disease Intervention/Treatment Early phase1
Dental caries Drug: Ferumoxytol /Hydrogen peroxide
Drug: Hydrogen Peroxide
Drug: Water
Early Phase 1
Periodontal Diseases Frankincense Extract
Phase 1
End-Stage Renal DiseaseHemodialysis
Catheter-associated Infection
Drug: catheter lock solution consisting of N-
acetylcystein, tigecycline and heparin
Phase 1

23. Conclusion:
• Bacteria have the ability to grow in both a free form(planktonic life style) or
as biofilms attached to various surfaces.
• Biofilms are complex communities of microorganisms attached to surfaces
and enclosed in matrix of extracellular polysaccharide matrix(EPS)
• Biofilm formation mainly depends upon environmental factors and
virulence factors such as quorum sensing
• Biofilm infections and its resistance to antimicrobial treatment , has posed
great challenge in the medical field.
• Further research has to be performed to find out the small active
fragments of these peptides and polysaccharides that can effectively bind
to the new identified targets

24. REFERENCES:
 https://doi.org/10.1016/j.jbiotec.2020.04.014
 https://www.sciencedirect.com/science/article/abs/pii/S0168165620301024
 Das Rina ,Mehta Kumar Dinesh, “Microbial Biofilm and Quorum Sensing Inhibition: Endowment of Medicinal
Plants to Combat Multidrug-Resistant Bacteria”, Current Drug Targets 2018; 19(16) .
https://doi.org/10.2174/1389450119666180406111143
 Stępień-Pyśniak, D., Hauschild, T., Kosikowska, U. et al. Biofilm formation capacity and presence of virulence
factors among commensal Enterococcus spp. from wild birds. Sci Rep 9, 11204 (2019).
https://doi.org/10.1038/s41598-019-47602-w
 Vestby LK, Grønseth T, Simm R, Nesse LL. Bacterial Biofilm and its Role in the Pathogenesis of Disease.
Antibiotics (Basel). 2020 Feb 3;9(2):59. doi: 10.3390/antibiotics9020059. PMID: 32028684; PMCID:
PMC7167820.