Enterococcus faecalis
Jose J. Ferrari D.D.S.
Graduate Endodontic Department
Case Western Reserve University
E. faecalis Characteristics
 Enterococcus faecalis formerly classified as Group D
Streptococcus.
 Gram-positive cocci th...
Cont. Characteristics
• E. faecalis can cause life-threatening infections in humans,
especially in the nosocomial (hospita...
Virulence Factors
 Aggregation Substance
− Biofilm formation helps resist Ca(OH)2
• Surface Adhesins
– Adhesins that faci...
Virulence factors
 Hyaluronidase
− Destroys CT
 Cytolysin
– Targets erythrocytes
 AS-48
– An antibiotic-like peptide fo...
Virulence Factors
 LTA (lipoteichoic acid) is involved in inflammatory
responses and sepsis syndrome biofilm formation an...
Scanning Electron
Microscope
Primary Endodontic Infections
 Polymicrobial
 Dominated by Gram-negative Anaerobic Rods
 E. faecalis is found in 4to 40...
Primary Endodontic Infection
Secondary Endodontic Infection
Persistence of Periapical Lesion
Why in Endodontic
Reinfection?
E. faecalis and Endodontic
failures
 E. faecalis is mostly associated with asymptomatic cases
 Despite making up a small...
E. faecalis: Endodontic RE-infections
 Very seldom found in primary root canal infections
– Sundqvist, JOE, 1992
 VERY f...
Ecology
 Enterococci have been described as extremely hardy
organisms capable of living in many mediums that
would certai...
E. faecalis Survival Within The
Root Canal System
 It exhibits widespread genetic polymorphisms
 It possesses serine pro...
Penetrance of E. faecalis in the
dentinal tubules
 Penetrates 250 m in the tubules
– Siren et al, 1997
 Bovine model pe...
E. faecalis Survival Within The
Root Canal System
 E. faecalis is able to form a biofilm that helps it resist
destruction...
Growth Phases of E. Faecalis
 Longitudinal growth vs. starvation phase
 When in the starvation phase, it can be 10,000 t...
Growth Phases cont...
 This starvation phase is poorly understood
 Is not a spore forming bacteria
 Synthesizes a myria...
Quick review on Calcium
Hydroxide
 Is the most commonly used intracanal medicament
 Calcium hydroxide releases hydroxyl ...
pH needed to kill E. Faecalis
 At pH of 10.5 to 11.0, growth of E. faecalis was
inhibited
– McHugh et al, 2004
 pH can o...
Adapts to the environment
 E. faecalis has a functioning proton pump that actually
pumps hydrogen ions to acidify the cyt...
Calcium Hydroxide and LTA
 Calcium hydroxide inactivation of LTA appears to occur
immediately (within 5 minutes) at a rel...
Therefore, E. faecalis is resistant
to Ca(OH)2
intracanal/interappointment
treatments
Current Strategies for
Eradication
 Preparing the apical portion of the root canal to a larger size
will help eliminate i...
Remove the Smear Layer!
 NaOCL to remove the ORGANIC component of the
smear layer
 17% EDTA to remove the INORGANIC comp...
Steps to Eliminate
E. faecalis
Enterococcus faecalis
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  • Produces a large amount of extracellular oxygen, one of the few bacteria that does so. E. faecalis has a cation homeostasis mechanisms, which likely contributes to its resistance to pH, salt, metal, and desiccation.
  • the occurrence of more than one form or morph .(subtypes)LTA has high affinity to hydroxyapatite (14), the released LTA could accumulate and persistently reside in the dentinal tubules, continuously stimulating the surrounding tissues.
  • LTAs tend to lose their acyl chains under high alkaline conditions
  • Transcript of "Enterococcus faecalis"

    1. 1. Enterococcus faecalis Jose J. Ferrari D.D.S. Graduate Endodontic Department Case Western Reserve University
    2. 2. E. faecalis Characteristics  Enterococcus faecalis formerly classified as Group D Streptococcus.  Gram-positive cocci that occur singly, in pairs, or in short chains.  Facultative anaerobes.  They catabolize a variety of energy sources including carbohydrates, glycerol, lactate, malate, citrate, arginine, agmatine, and many α keto acids.  Displays gamma hemolysis on sheep’s blood agar
    3. 3. Cont. Characteristics • E. faecalis can cause life-threatening infections in humans, especially in the nosocomial (hospital) environment. • Major nosocomial pathogens causing bacteremia, endocarditis, bacterial meningitis, urinary tract, and various other infections  Live in vast quantities in the human intestinal lumen.  They are common in environments contaminated by human and animal faecal materials (e.g. urban sewage, recipient water, and soil receiving fertilizers of animal origin), as well as in food products derived from animals  Present in human female genital tract and oral cavity in lesser numbers.
    4. 4. Virulence Factors  Aggregation Substance − Biofilm formation helps resist Ca(OH)2 • Surface Adhesins – Adhesins that facilitate specific binding of enterococci to intestinal epithelium, renal epithelial cells, human neutrophils, and macrophages  Superoxide formation – Tissue destruction – Neutrophil chemo-attractant  Gelatinase formation (GelE) − Can hydrolyse gelatin, casein, haemoglobin, and other bioactive peptides.
    5. 5. Virulence factors  Hyaluronidase − Destroys CT  Cytolysin – Targets erythrocytes  AS-48 – An antibiotic-like peptide found in some strains of E. Faecalis – Competition with other bacteria
    6. 6. Virulence Factors  LTA (lipoteichoic acid) is involved in inflammatory responses and sepsis syndrome biofilm formation and adhesion to teeth because of its absorptive activity to hydroxyapetite
    7. 7. Scanning Electron Microscope
    8. 8. Primary Endodontic Infections  Polymicrobial  Dominated by Gram-negative Anaerobic Rods  E. faecalis is found in 4to 40% of primary endodontic infections − et al Rocas, Siqueira JOE 2004 Secondary Endodontic Infections • Compose of one or a few bacterial species  Predominantly Gram-positive microorganisms  9 times more likely to contain E. faecalis than primary endodontic infections
    9. 9. Primary Endodontic Infection
    10. 10. Secondary Endodontic Infection
    11. 11. Persistence of Periapical Lesion
    12. 12. Why in Endodontic Reinfection?
    13. 13. E. faecalis and Endodontic failures  E. faecalis is mostly associated with asymptomatic cases  Despite making up a small proportion of the flora in untreated canals, plays a major role in the etiology of persistent periradicular lesions after root canal treatment.  It is commonly found in a high percentage of root canal failures and it is able to survive in the root canal as a single organism or as a major component of the flora
    14. 14. E. faecalis: Endodontic RE-infections  Very seldom found in primary root canal infections – Sundqvist, JOE, 1992  VERY frequently found in endodontic RE-infections that have signs of chronic apical periodontitis – Engstrom, 1964, Moller, 1966  Can often occur as a monoculture in infected and treated root canals – Sundqvist, 1998
    15. 15. Ecology  Enterococci have been described as extremely hardy organisms capable of living in many mediums that would certainly kill other bacteria.  Capable of survival at 60 degrees Celsius for 30 minutes.  Enterocoocus faecalis is able to grow in 6.5% NaCl. Enterococci can also grow in 40% bile salts and over a broad range of pH.  Enterococci also have a large amount of natural antibiotic resistance.
    16. 16. E. faecalis Survival Within The Root Canal System  It exhibits widespread genetic polymorphisms  It possesses serine protease, gelatinase, collagen- binding proteins (ACE), help to bind to dentin  It can invade and live within dentinal tubules (250- 400 microns)  It has the capacity to endure prolonged periods of starvation  Once nutritional supply become available starved cells are able to recover by utilizing serum
    17. 17. Penetrance of E. faecalis in the dentinal tubules  Penetrates 250 m in the tubules – Siren et al, 1997  Bovine model penetrates 300-400 m – Haapasalo, 1987  Penetrance of bacteria is retarded with keeping of the smear layer – Haapasalo, 1987 – Case for keeping the smear layer?
    18. 18. E. faecalis Survival Within The Root Canal System  E. faecalis is able to form a biofilm that helps it resist destruction by enabling the bacteria to become 1000 times more resistant to phagocytosis, antibodies and antibacterials  In dentinal tubules it can resist intracanal dressings of calcium hydroxide for over 10 days  E. faecalis is less dependent upon virulence factors, it relies more upon its ability to survive and persist as a pathogen in the root canals of teeth.
    19. 19. Growth Phases of E. Faecalis  Longitudinal growth vs. starvation phase  When in the starvation phase, it can be 10,000 times more resistant to medicaments than when in its longitudinal growth phase – Portenier et al, 2005  More resistant to UV radiation, heat, NaOCl, H2O2, EtOH, and acid. – Giard et al, 1996  This viable but non-cultivable (VBNC) state may explain how it is a monoinfection in obturated canals  Return when the environment is more favorable for growth
    20. 20. Growth Phases cont...  This starvation phase is poorly understood  Is not a spore forming bacteria  Synthesizes a myriad of genes in order to cope with its harsh environment and make energy – Giard et al, J Bacteriol, 2000
    21. 21. Quick review on Calcium Hydroxide  Is the most commonly used intracanal medicament  Calcium hydroxide releases hydroxyl ions in aqueous solutions, resulting in a high alkaline environment where most bacteria cannot survive  Is antimicrobial by raising the pH of the root canal environment  Dissolves tissue – Wadaki, Araski, Suda, Hasselgren
    22. 22. pH needed to kill E. Faecalis  At pH of 10.5 to 11.0, growth of E. faecalis was inhibited – McHugh et al, 2004  pH can only reach up to 10.3 because of the buffering effect of dentin.  pH gradient decreases deeper in the dentinal tubules  11.5 was necessary to eradicate
    23. 23. Adapts to the environment  E. faecalis has a functioning proton pump that actually pumps hydrogen ions to acidify the cytoplasm in highly alkaline conditions – McHugh, Evans, 2002
    24. 24. Calcium Hydroxide and LTA  Calcium hydroxide inactivation of LTA appears to occur immediately (within 5 minutes) at a relatively low calcium hydroxide concentration (2.5 mg/mL).  Currently, the mechanism for inactivation of LTA by calcium hydroxide is unknown. − deacylation of LTA et al Baik, Kum JOE 2008 (November)
    25. 25. Therefore, E. faecalis is resistant to Ca(OH)2 intracanal/interappointment treatments
    26. 26. Current Strategies for Eradication  Preparing the apical portion of the root canal to a larger size will help eliminate intracanal microorganisms  Full strength NaOCl is still effective against E. faecalis – Needs to be in contact – No substantivity  Need to be able to penetrate the tubules where they like to hide  Chlorhexidine is effective against E. faecalis – Smear layer prevents its contact – Has substantivity
    27. 27. Remove the Smear Layer!  NaOCL to remove the ORGANIC component of the smear layer  17% EDTA to remove the INORGANIC component of the smear layer  Final rinse with 2% CHX in the canal now that the tubules are opened up  Good technique for primary NSRCT’s  A MUST for NS RETX
    28. 28. Steps to Eliminate E. faecalis
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