Biofilms

5,205 views

Published on

0 Comments
4 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
5,205
On SlideShare
0
From Embeds
0
Number of Embeds
1,004
Actions
Shares
0
Downloads
290
Comments
0
Likes
4
Embeds 0
No embeds

No notes for slide

Biofilms

  1. 1. Bacterial Biofilms: A general view Blgo. Carlos A. Fernández Miñope FernandezC4@gmail.com – Marzo, 2014 Segunda Especialidad en Microbiología Clínica Hospital Regional Lambayeque Universidad Nacional Pedro Ruiz Gallo
  2. 2. What are Biofilms? • Biofilms are communities of surface-associated microorganisms encased in a self-produced extracellular matrix. • Biofilm formation is a nearly universal bacterial trait, and biofilms are found on almost all natural and artificial surfaces • Some examples of biofilms are the plaque that forms on teeth and the slime that forms on surfaces in watery areas. Blgo.CarlosA.FernándezMiñope
  3. 3. Biofilms are everywhere Blgo.CarlosA.FernándezMiñope Biofilms appear early in the fossil record. There is evidence of biofilm formation early in the fossil record, particularly in hydrothermal environments.
  4. 4. Blgo.CarlosA.FernándezMiñope High-resolution scanning electron microscopy image of a community- associated methicillin-resistant Staphylococcus aureus biofilm embedded in extracellular matrix, formed on implanted catheter tubing during experimental biofilm infection. M. Otto, D. Dorward, E. Fischer and A. Mora, National Institute of Allergy and Infectious Diseases, USA.
  5. 5. Blgo.CarlosA.FernándezMiñope Human Infections linked to biofilms
  6. 6. A simple view: B. subtilisbiofilm formation Blgo.CarlosA.FernándezMiñope Vlamakis, H., Chai, Y., Beauregard, P., Losick, R., Kolter, R. Sticking together: building a biofilm the Bacillus subtilis way. Nature Reviews Microbiology, 11: 157-168 (2013).
  7. 7. Blgo.CarlosA.FernándezMiñope Vlamakis, H., Chai, Y., Beauregard, P., Losick, R., Kolter, R. Sticking together: building a biofilm the Bacillus subtilis way. Nature Reviews Microbiology, 11: 157-168 (2013).
  8. 8. A closer look at biofilms Extracellular Matrix Blgo.CarlosA.FernándezMiñope In situ observations of biofilm structure using confocal laser microscopy showed sessile bacteria growing in heterogeneous matrix-enclosed microcolonies interspersed with open water channels.
  9. 9. Blgo.CarlosA.FernándezMiñope Thecomplexstructureof bacterialbiofilms McDougald, D., Rice, S., Barraud, N., Steinberg, P., Kjelleberg, S. Should we stay or should we go: mechanisms and ecological consequences for biofilm dispersal . Nature Reviews Microbiology, 10: 39-50 (2010). ΔPf4
  10. 10. Blgo.CarlosA.FernándezMiñope Oralbacterialcolonization Kolenbrander, P.E., Palmer, R.J., Periasamy, S., Jakubovics, N.S. Oral multispecies biofilm development and the key role of cell– cell distance. Nature Reviews Microbiology, 8: 471-481 (2010).
  11. 11. There is a strong relationship between the cell’s environment and its physiology and structure. Science News Biofilms form Nutrient levels decrease towards the center Variety of environmental niches form Blgo.CarlosA.FernándezMiñope Biofilm formationand growth
  12. 12. • Quorum sensing and chemical signaling • Microcolonies with extracellular matrix • Network of channels • Cells experience different environmental conditions • Multi-species Blgo.CarlosA.FernándezMiñope Biofilm formation and growth
  13. 13. Stages of Biofilm Formation Bacteria switch from a free-floating (planktonic) state where they function as individuals to a sessile state where they function as communities. Blgo.CarlosA.FernándezMiñope
  14. 14. Watnick, P., Kolter, R. Biofilm, City of microbes. J. Bacteriol. 182 (10): 2675-2679 (2000). Biofilm formation in Vibrio cholerae
  15. 15. Blgo.CarlosA.FernándezMiñope Candida albicans biofilmstructureinvitroandinvivo Scanning electron micrograph (SEM) of an in vitro Candida albicans biofilm. The biofilm sample was sliced to show three layers in a cross- sectional view. SEM of an in vivo C. albicans biofilm from the rat catheter model. Images of J. Suhan (Carnegie Mellon University, Pittsburgh, Pennsylvania, USA), and J. Nett and D. Andes (University of Wisconsin–Madison, USA).
  16. 16. Singh, P.K., Schaefer, A.L., Parsek, M.R., Moningerk, T.O., Welsh, M.J., Greenberg, E.P. Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms. Nature 407: 762- 764 (2000). In the microscopic examination of sputum from patients colonizated by P. aeruginosa reveled that they are encased in a densely stained matrix. This appearance is consistent with previous microscopic observations and consistent with the hypothesis that in CF sputum, P. aeruginosa exists in biofilms. a, Low magnification; b, high magnification. Blgo.CarlosA.FernándezMiñope
  17. 17. In P. aeruginosa, differentiation is cued by one of two quorum- sensing signals N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL) and N-butyryl-LHSL (C4-HSL). The signal required for microcolony differentiation in biofilms is 3OC12-HSL). Singh, P.K., Schaefer, A.L., Parsek, M.R., Moningerk, T.O., Welsh, M.J., Greenberg, E.P. Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms. Nature 407: 762-764 (2000). C4-HSL as a fraction of the total C4-HSL plus 3OC12- HSL. From left to right, P. aeruginosa in early logarithmic (A600 = 0.5), mid-logarithmic (A600 = 1), late logarithmic (A600 = 2), stationary (A600 = 4) and late stationary phase (A600 = 6). C4-HSL 1 C4-HSL 3 C4-HSL 66 3OC12-HSL 3 3OC12-HSL 1 3OC12-HSL 1 A/(A+B) = 0.25 A/(A+B) = 0.75 A/(A+B) = 0.99 Incremento de 3OC12-HSL Incremento de C4-HSL Blgo.CarlosA.FernándezMiñope C4-HSL 1 C4-HSL 3 C4-HSL 66 3OC12-HSL 3 3OC12-HSL 1 3OC12-HSL 1 A/(A+B) = 0.25 A/(A+B) = 0.75 A/(A+B) = 0.99 Incremento de 3OC12-HSL Incremento de C4-HSL QUORUM SENSING
  18. 18. Singh, P.K., Schaefer, A.L., Parsek, M.R., Moningerk, T.O., Welsh, M.J., Greenberg, E.P. Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms. Nature 407: 762-764 (2000). The findings are consistent with the hypothesis that P. aeruginosa in CF lungs exist as a biofilm. Blgo.CarlosA.FernándezMiñope QUORUM SENSING
  19. 19. Whiteley, M., Bangera, M.G., Bumgarner, R.E., Parsek, M.R., Teitzel, G.M., Lory, S., Greenberg, E.P. Gene expression in Pseudomonas aeruginosa biofilms. Nature 413: 860-864 (2001). Genes for synthesis of pili and flagella are repressed in biofilms. Pili and flagella are reported to be involved in the initial steps (attachment and microcolony formation) of development of P. aeruginosa biofilms. These appendages may not be required for maintenance of a mature biofilm. Once development has proceeded through these steps, pili and flagella are no longer required. Blgo.CarlosA.FernándezMiñope Diferential gene expression
  20. 20. Blgo.CarlosA.FernándezMiñope Coordinatedcell-deathis necessaryto maintainthe biofilm A confocal image (400× magnification) showing a mixed population of live (green) and dead (red) Staphylococcus aureus cells within a 3-day-old biofilm. Image by Ethan Mann, University of Nebraska Medical Center, Nebraska, USA. The cidABC and lrgAB operons of S. aureus regulate cell lysis during the stationary phase of growth and in response to antibiotic exposure. There are homologues of cid/lrg genes present in a wide range of Gram-positive and Gram- negative bacteria.
  21. 21. Moving of bacteria in biofilms Blgo.CarlosA.FernándezMiñope
  22. 22. Blgo.CarlosA.FernándezMiñope Activebiofilmdispersalandvariantformation McDougald, D., Rice, S., Barraud, N., Steinberg, P., Kjelleberg, S. Should we stay or should we go: mechanisms and ecological consequences for biofilm dispersal . Nature Reviews Microbiology, 10: 39-50 (2010). Each biofilm population becomes a mutator
  23. 23. Hall-Stoodley, L., Costerton, J.W., Stoodley, P. Bacterial biofilms: from the natural environment to infectious diseases. Nature Reviews Microbiology, 2: 95-108 (2004). Bacterial endocarditis shows how microorganisms on the skin or in the oral cavity that transiently enter the bloodstream can colonize abnormal or implanted valves, or altered endothelial surfaces in the heart. Blgo.CarlosA.FernándezMiñope
  24. 24. Hall-Stoodley, L., Costerton, J.W., Stoodley, P. Bacterial biofilms: from the natural environment to infectious diseases. Nature Reviews Microbiology, 2: 95-108 (2004). Blgo.CarlosA.FernándezMiñope
  25. 25. Blgo.CarlosA.FernándezMiñope ProgressionofStaphylococcusaureusfroman infectedorcontaminatedsourcethroughthe bloodstreamtoametastatictarget Thwaites, G.E., Gant, V. Are bloodstream leukocytes Trojan Horses for the metastasis of Staphylococcus aureus? Nature Reviews Microbiology, 9: 215-222 (2011).
  26. 26. Blgo.CarlosA.FernándezMiñope Multiplicity of phenotypicstatesin biofilms Stewart, P.S., Franklin, M.J., Physiological heterogeneity in biofilms. Nature Reviews Microbiology, 6: 199-210 (2008).
  27. 27. • High diversity • Less parallelism • Each biofilm population becomes a mutator Blgo.CarlosA.FernándezMiñope
  28. 28. Blgo.CarlosA.FernándezMiñope Scanning electron micrograph of an untreated biofilm of S. epidermidis (a) and an identical biofilm exposed to vancomycin and rifampin for 72 h at concentrations exceeding the MIC and MBC for the organism (b). Despite obvious changes in the treated biofilm, viable organisms were recovered for which the MIC and MBC of both agents were unaltered. Photo: American Society for Microbiology. Drugresistancein Biofilms
  29. 29. Blgo.CarlosA.FernándezMiñope Time-and dose-dependentkilling of biofilms by metals Harrison, J.J., Ceri, H., Turner, R.J., Multimetal resistance and tolerance in microbial biofilms. Nature Reviews Microbiology, 5: 928-938 (2007). a) In vivo b) In vitro
  30. 30. Blgo.CarlosA.FernándezMiñope Drug resistance in Biofilms mediatedby persistercells Lewis, Kim. Persister cells, dormancy and infectious disease. Nature Reviews Microbiology, 5: 48-56 (2007).
  31. 31. Blgo.CarlosA.FernándezMiñope Formationof persistercells Lewis, Kim. Persister cells, dormancy and infectious disease. Nature Reviews Microbiology, 5: 48-56 (2007). The treatment of a population with an antibiotic results in cell death, leaving only persister cells or resistant mutants alive
  32. 32. Multiresistant Bacteria • Horizontal gene transfer is promoted in biofilms; therefore, it is possible that antibiotic resistance spreads more easily than in planktonic populations Blgo.CarlosA.FernándezMiñope
  33. 33. Blgo.CarlosA.FernándezMiñope
  34. 34. Existence in a biofilm induces moderate levels of resistance to all antimicrobial treatments. This could afford cells in a biofilm the opportunity to respond to an antibiotic by inducing genes more specific to that antibiotic. We compared biofilms exposed to tobramycin with untreated biofilms. Consistent with our hypothesis, 20 genes were differentially expressed in tobramycin-treated biofilms: 14 were activated and 6 were repressed by tobramycin (seven times the minimum inhibitory concentration for planktonic cells). Of these 20 genes, 12 were classified as genes coding for hypothetical proteins of unknown function. As expected, treatment with tobramycin, which causes errors in protein synthesis, seemed to induce a stress response, with activation of dnaK and groES genes, for example. Tobramycin strongly induced several genes coding for hypothetical proteins. Whiteley, M., Bangera, M.G., Bumgarner, R.E., Parsek, M.R., Teitzel, G.M., Lory, S., Greenberg, E.P. Gene expression in Pseudomonas aeruginosa biofilms. Nature 413: 860-864 (2001). Blgo.CarlosA.FernándezMiñope
  35. 35. Whiteley, M., Bangera, M.G., Bumgarner, R.E., Parsek, M.R., Teitzel, G.M., Lory, S., Greenberg, E.P. Gene expression in Pseudomonas aeruginosa biofilms. Nature 413: 860-864 (2001). Survival of cells in wild-type and rpoS-mutant biofilms after treatment with the antibiotic tobramycin. Open symbols, planktonic cultures; filled symbols, biofilms; squares, parent strain PAO1; triangles, rpoS mutant. At tobramycin concentrations above 5 mg ml -1 there were 2 viable cells ml -1 in planktonic cultures. Blgo.CarlosA.FernándezMiñope
  36. 36. Hall-Stoodley, L., Costerton, J.W., Stoodley, P. Bacterial biofilms: from the natural environment to infectious diseases. Nature Reviews Microbiology, 2: 95-108 (2004). Taken together, the data indicate that the ability to form biofilms is an ancient and integral characteristic of prokaryotes. In the context of EVOLUTION AND ADAPTATION it is likely that biofilms provided homeostasis in the face of the fluctuating and harsh conditions of the primitive earth (extreme temperatures, pH and exposure to ultraviolet (UV) light. Blgo.CarlosA.FernándezMiñope Biofilms are not new
  37. 37. Conceptualization of biofilm development and dynamic behaviours. Biofilms are structurally and dynamically complex biological systems Hall-Stoodley, L., Costerton, J.W., Stoodley, P. Bacterial biofilms: from the natural environment to infectious diseases. Nature Reviews Microbiology, 2: 95-108 (2004). Blgo.CarlosA.FernándezMiñope

×