au14_-_pediatric_dent_final_exam_20141210195054 Flashcards
What are the 3 ways discussed to detect bacterial species? What are the limitations of each?
- MICROSCOPY: difficult to distinguish similar morphotypes- CULTIVATION: special nutrient requirements; inhibition of some species by others; minor species overgrown; slow growing species overgrown- 16S SEQUENCING: rDNA gene alignments construct phylogenetic trees (not really a limitation…)
In the oral cavity, what proportion of the species have been cultivated?
over half (300+ species)
How many organisms are present in the oral cavity by cultivation? By 16 S sequence diversity? How many species are in each person?
- by cultivation, 300+ species- by 16S sequence diversity, around 700 species- each person harbors 100-200 species
The mouth is an open system. We have ___ species vs. ___ of the oral cavity that grow.
- transient species- true residents
What factors lead to bacterial diversity in the species that are adapted to the oral cavity and those who are transient?
contact with:- water- soil- plants- animals- other humans- other body sites
What are the 4 purposes/goals of the Human Microbiome Project?
- determining whether individuals share a core human microbiome- understanding whether changes in the human microbiome can be correlated with changes in human health- developing the new technological and bioinformatic tools needed to support these goals- addressing the ethical, legal, and social implications raised by human microbiome research
True or false: Each of us includes more bacterial cells than human cells.
true (our microbiota includes many-fold more DNA variety than our human genome)
What are the different body sites that have distinct microbial communities?
- oral cavity- gastrointestinal- urogenital- skin- nasal
Describe how the human oral microbiome is acquired. (include the study that addressed this)
- study tested the hygiene hypothesis (“don’t kiss babies or share utensils to avoid transmission of S. mutans)- study looked at babies in the NICU vs. babies that were home-reared- after 1 day, the difference between the babies was significant, but after 3 months, the babies were very similar in bacterial load
What is the definition of ecology? Of a niche?
- ECOLOGY: study of the interrelationships of organisms and their environment- NICHE: a specific combination of conditions that are necessary for the survival of a particular organism; parameters may be physical, chemical, and biological
The mouth has multiple niches:- non-shedding hard surfaces of teeth are unique because microorganisms can form ___- microorganisms can invade soft tissues, as in ___ and ___.
- stable, thick biofilms called “dental plaque”- periapical and odontogenic infections
How do oral structures change over time?
- teeth erupt and are lost- pockets form (caused by bacteria)- injuries occur
Name the oral surfaces to which bacterial adhere.
SOFT-TISSUE SURFACES:- sulcus, tongue, mucosa, gingivaHARD SURFACES:- supragingival: fissures (*most common), proximal surfaces, buccal and lingual enamel surfaces, cementum, restorations, calculus- subgingival: enamel, cementum, restorations, calculus
Some bacteria are ___, but most of the bacteria that cause dental problems and many medical problems are ___.
- planktonic (floating in water)- sessile (attached to surface of biofilm)
Biofilms are made up of ___ and ___ in a ___ environment.
- adherent microorganisms- extracellular matrix- aqueous environment
What is the extracellular matrix of a biofilm?
- bacteria adhere to surfaces in aqueous environments and excrete a slimy glue-like substance that can anchor them to surfaces such as tooth, metal, plastics, medical implant materials, and tissue- sticky material that hold the biofilm together is called the extracellular matrix!- water flows through channels in the matrix like a circulatory system
What is the biofilm life cycle?
- attachment- growth to mature biofilm community- detachment of cells to seed a new biofilm formation
Describe the composition of a biofilm.
- can be formed by a single bacterial species, but more often, includes many species of bacteria- may also include other microorganisms like fungi, algae, or protozoa
What is quorum sensing?
used by bacteria to know when there is a group large enough to do a specific activity
When are biofilm-adaptive genes turned on?
- bacteria detect surfaces- bacteria detect each other (quorum sensing)- signals pass between bacteria
How do multiple species co-exist and cooperate in a biofilm?
- provide nutrients for each other (food chains)- remove toxins- inter- and intra-species signaling is important- “division of labor” within the same species and among species
What are biofilms resistant to?
- antibiotics- host defense- mechanical disruption
True or false: Antibiotic doses that kill biofilm cells need to be increased as much as 1000-fold to kill suspended cells.
FALSE. Antibiotic doses that kill suspended cells need to be increased as much as 1000-fold to kill biofilm cells.
What are the primary mechanisms for biofilm antimicrobial resistance?
- slowing of diffusion- “persister cells” that are alive but metabolically inactive survive and repopulate- close proximity and exchange of resistance genes
Are most bacteria in the mouth planktonic or in a biofilm? Is saliva considered a “sink of media”?
- most are attached in biofilms- saliva is just a thin film a few microns thick on oral structures, not a sink of media
What oral problems can be caused by biofilms?
- caries- periodontitis- osteomyelitis- osteonecrosis secondary to bisphosphonate therapy (anti-osteoclastic drug)
True or false: Preventing oral biofilms would prevent some invasive diseases as well
true
What are the 6 factors that contribute to the environment in the oral cavity and create specific niches?
- bacterial adherence- oxygen tension- pH- bacterial food supply or substrate- host inhibitory factors- bacterial community interactions
What are the surface sites for bacterial adherence to make biofilms? What common measures are used to disrupt bacterial adherence in the mouth?
- host surfaces (receptor molecules)- direct bacterial interactions- extracellular matrix- tooth brushing and flossing
What is salivary binding? What molecules are involved?
- promotes bacterial adherence by providing binding sites or inhibits by agglutinating and clearing- antibodies (acquired immunity)- salivary agglutinins- proline-rich glycoproteins- alpha-amylase
What is the % of oxygen in the air? In the closed mouth? In the periodontal pocket? In the supragingival plaque?
- air: 21%- closed mouth: 12-14%- periodontal pocket: 1-2%- supragingival plaque: 1-20% depending on age of the plaque
What is the oxidation-reduction potential (Eh)? What does a positive Eh mean? A negative Eh?
- electrical potential or tendency to oxidize or reduce (oxygen level)- positive Eh = aerobes (high oxygen)- negative Eh = anaerobes (low oxygen)
What is the difference between obligate anaerobes, facultative anaerobes, microaerophilic, aerotolerant anaerobes, and obligate anaerobes?
- OBLIGATE ANAEROBES: require oxygen at atmospheric levels for growth- FACULTATIVE ANAEROBES: can switch between aerobic and anaerobic metabolism- MICROAEROPHILIC: require low levels of oxygen- AEROTOLERANT ANAEROBES: anaerobic metabolism but can tolerate the presence of oxygen (*mostly in oral cavity!)- OBLIGATE ANAEROBES (AEROPHOBES): do not use oxygen as a nutrient and oxygen is toxic (kills or inhibits growth)
What are the 2 mechanisms of oxygen toxicity?
- causes oxidation of membrane lipids and destruction of cell integrity- causes oxidation of sulfhydryl groups in enzymes resulting in cross-linking and inactivity
What enzymes cannot be made in anaerobes? In the absence of these enzymes, what is produced?
- superoxide dismutase, catalase, or various peroxidases- superoxide and peroxide that can damage the cell
Where are anaerobic species found in tooth biofilms? Facultative and microaerophilic species? What species scavanges oxygen to help provide an anaerobic environment?
- oxygen-protected sites like the sulcus or mature coronal plaque- supragingival plaques- Fusobacterium
What common therapy is designed to exploit the oxygen sensitivity of oral bacteria?
peroxide
What is the normal oral pH? What may affect that pH?
- pH 7.0 (usually ranges from 5 (sugar fermentation) to 7.5 - direct affect: carbonated soft drink (pH 3)- indirect affect: bacterial fermentation of sugars to lactate (pH 5)
A low pH inhibits most oral species except ___.
acid tolerant strep and lactobacilli
What are the 2 major nutrient niches in the oral cavity?
- supragingival environment: saliva (endogenous) and ingested food (exogenous)- subgingival environment: crevicular fluid and cells (endogenous)
How are different types of exogenous nutrients ingested by bacteria in the oral cavity?
- low MW soluble carbohydrates and amino acids are readily taken up by bacteria- starches and proteins must be retained (sticky foods) for bacterial digestion
What are the endogenous nutrient sources? What does each contain?
- SALIVA: contains glycoproteins, inorganic salts, amino acids, glucose, vitamins- SHED HOST CELLS- GINGIVAL CREVICULAR FLUID: contains tissue and serum proteins, amino acids, glucose, vitamins, hemin (especially in gingivitis), hormones (estradiol, progesterone); degree of inflammation influences flow and composition- BREAKDOWN PRODUCTS FROM PERIODONTAL TISSUES (from bacterial proteases and host inflammatory degradation)
True or false:1. Endogenous nutrients are sufficient for plaque.2. Endogenous nutrients are sufficient for caries.
- true (tube-fed patients have abundance of both supra- and subgingival plaque)2. FALSE. (need exogenous carbohydrate for caries)
What antibody is present in the saliva? In the crevicular fluid? Where are they produced? What do they do?
- sIgA (secretory immunoglobulin A) in saliva; prevents adhesion- IgG in crevicular fluid directly against peridontally important organisms- both systemically and locally produced- inhibit colonization, act as opsonins, and activate complement system
What are the 5 modes of innate immunity in the oral cavity?
- epithelial barrer and desquamation (soft tissues)- saliva flow- neutrophils (95% of leukocytes in crevicular fluid)- complement proteins from crevicular fluid- antimicrobial peptides produced in salivary glands, epithelium, and immune cells (defensins, histatins, cathelicidins)
What are the major salivary proteins? What are the mechanisms of saliva for maintaining the integrity of the tooth?
- alpha-amylase (digests starch and binds bacteria) and mucins (lubricants)- pellicle proteins/salivary minerals; salivary buffering
What are the 5 minor salivary proteins/defenses? What does each do?
- SALIVARY LYSOZYME: digests peptidoglycan in bacterial cell wall leading to osmotic disruption and cell death- SALIVARY LACTOFERRIN AND SERUM TRANSFERRIN: proteins that bind iron so that it is not bioavailable to bacteria- SIALOPEROXIDASE SYSTEM: generates superoxide radicals which inactivate bacterial enzymes leading to bacterial death- ANTIMICROBIAL PEPTIDES: have activity against bacteria and yeast- ACIDIC PROLINE-RICH PROTEINS AND STATHERIN: modulate salivary calcium and phosphate chemistry
Describe the food chain of lactic acid
- Strep produces lactic acid by metabolism of sugars- Veillonella requires lactate and converts it to propionate etc. and raises the pH for acid-sensitive Strep
Describe the food chain of vitamin K3 (menadione).
- Veillonella parvula synthesizes vitamin K3- used by P. gingivalis and P. intermedia
Who generates carbon dioxide in the biofilm? Whose growth is enhanced?
- generated by a number of organisms including peptostreptococci and Eubacteria- enhances growth of Capnocytophaga and A. actinomycetemcomitans
What bacteria removes oxygen from the biofilm and what bacteria survives because of it?
- Fusobacterium nucleatum/periodonticum- Tanerella forsythia
What are the 3 bacterial community interactions?
- bacterial products as nutrients (complex food chains)- bacterial products altering environment (oxygen/carbon dioxide availability)- microbial inhibitory factors
What are the major oral niches/ecosystems for bacteria?
- supragingival tooth surface and dorsum of tongue- gingival crevice (subgingival tooth and crevicular epithelial surface)
Saliva contains bacteria shed from all ecosystems - what are the implications for collecting samples for clinical diagnostic tests?
limitations because there are things being diluted, etc.; if you want to know what is going on in the tooth, look at the tooth
What are 3 ways microbes can be beneficial?
- resistance against pathogens- metabolic functions- immune activation
Describe the paradigm shift in microbiology.
- germs (bacteria = pathogenic invaders) –> microbes are essential- goal is sterile environment –> preserve native microbes- Koch’s postulates & single-species acute diseases –> chronic diseases caused by microbial community disruptions (rather than invasive pathogen)- therapies focused on broad eradication (antibiotics/antiseptic) –> therapies to encourage healthy communities (probiotics/prebiotics/targeted antimicrobials)
The oral microbiome includes approximately ___ species of bacteria.
1000
What phyla of bacteria is most common in the oral cavity? What genera?
- firmicutes- streptococcus
What is the Theory of Focal Infection?
idea that removing oral “focus of infection” could cure systemic disease; goes back to ancient times (Hippocrates reported the cure of arthritis after removal of a tooth)(theory was challenged and discredited by 1930)
What do all of these diseases have in common?- cardiovascular disease- type 1 diabetes- infective endocarditis- cardiovascular implantable electronic devices (CIED)- prosthetic joints- bone pins, plates, and screws- intravascular access devices- cerebrospinal fluid (CSF) shunts- vascular grafts- pneumonia- immunosuppression- preterm birth- systemic lupus erythematosus
diseases that may have oral-systemic connections
How can causality be established to link oral-systemic effects?
- trials showing treatment effect (ex. remove periodtonal disease to see if heart disease reduces)- metastatic presence of bacteria- model systems
What are the 3 mechanisms for oral-systemic connections? Describe each.
- distant site infection seeded by oral bacteria (oral bacteria gain entry to circulatory system (bacteremia) or airway (aspiration))- distant site injury from toxin produced by bacteria in oral cavity (oral bacterial produces (such as endotoxin) gain access to circulatory system)- host genetic hyper-susceptibility to inflammation is common pathway to disease (ex. a genetic hyper-reactive host innate immune response may be a common predisposing factor for periodontitis, cardiovascular disease, obesity, etc.)
How can bacteremia be prevented?
- antibiotic prophylaxis- improved oral health
Describe the progression of Infective Endocarditis.
- platelets and fibrin adhere to exposed connective tissues producing “vegetation” or nonbacterial thrombotic endocarditis (NBTE)- bacteria from distant site (oral cavity!) enter blood stream (bacteremia) and adhere to NBTE- bacteria multiply and infiltrate heart tissues causing cardiac and valvular injury- discharged into circulation producing emobli and stroke
What bacteria are usually associated with Infective Endocarditis?
- Streptococci (sanguis, mitis group, mutans) (60+%)- Aggregatibacter actinomycetemcomitans- Gemella- Staphylococci (skin bacteria) (25+%)
What is antibiotic prophylaxis used for? What risks are associated with it? Is it successful?
- in theory, AP prevents hematogenous spread of bacteria (bacteremia)- risks: allergy, resistance- in practice, AP does not prevent bacteremia and is unlikely to prevent many cases of infective endocarditis
True or false: No evidence is available that dental procedures are associated with Infective Endocarditits.
true (random bacteremia from routine daily activities like chewing food or brushing are more likely to cause IE)
What is the most successful way to reduce risk of Infective Endocarditis?
more important to optimize regular oral hygiene measures to keep bacterial load low than to give antibiotic prophylaxis
Indications for antibiotics prophylaxis are based on what 2 factors? What antibiotic is usually used?
- invasiveness of procedure- high risk of infective endocarditis- single high dose of amoxicillin
Who is most susceptible to pneumonia caused by oral bacteria? What is the best way to prevent lung infections?
- those with poor airway protective reflexes (physically handicapped, elderly)- improved oral hygiene measures prevent lung infection (reduce nosocomial pneumonia by 40% and prevent 1/10 deaths in elderly in nursing homes)
Do randomized clinical trials show periodontal treatment reduces the risk of preterm birth or low birth weight? How are preterm birth and oral bacteria related? Is the evidence for causal relationship strong or weak?
- do NOT show periodontal treatment reduces risk- bacteria in amniotic fluid (some common oral species) associated with preterm birth- evidence for causal relationship NOT strong
Immunosuppressed individuals have a higher risk for what types of infections?
disseminated Strep or Candida of oral origin
Are dental treatment or antibiotics successful for prevention of oral-systemic infections in immunosuppressed individuals? What else can be used?
- lack of evidence for relationship to dental treatment or efficacy of antibiotics- focus on achieving/maintaining good oral health; consider invasiveness of procedure, bacterial load, and degree of immunosuppression
What are the thoughts on Cardiovascular Implantable Electronic Device infections as a result of oral species?
- CIED infections caused by bacteria from skin of patients or from hands of hospital workers or environment (Staph, etc.), not oral species- AHA guidelines: Nonvalvular Cardiovascular Device Related Infections 2003 recommend NO antibiotic prophylaxis for dental treatment
What are the thoughts on vascular grafts/stents infection as a result of oral species?
- most infections (90%) caused by bacteria native to skin or bowel- oral organisms rarely infective agent, but mortality rates are high- AHA guidelines: Nonvalvular Cardiovascular Device Related Infections 2003 recommend NO antibiotic prophylaxis for dental treatment
What are the thoughts on intravascular access device infections as a result of oral species?
- infections usually caused by Staph or other skin or environmental bacteria- CDC Guidelines for Prevention of Intravascular Catheter-Related Infections 2011 recommend NO antibiotic prophylaxis for any reason (good infection control practices and monitoring are key)
What are the thoughts on joint prostheses infections as the result of oral species?
- 1-2% become infected; mobidity high- most often Staphylococci, but 5% by bacteria found in oral cavity- dental procedures unrelated to implant infection; evidence for protection by antibiotic prophylaxis prior to dental treatment lacking- American Academy of Orthopaedic Surgeons/ADA Guidelines 2012: consider discontinuing the practice of routine prophylactic antibiotics when undergoing dental procedures; patient preference should be considered; maintain appropriate oral hygiene (emphasis!)
What is the difference between primary and secondary prophylaxis? What are the thoughts on each?
- PRIMARY ANTIBIOTIC PROPHYLAXIS: at the time of device placement; evidence-supported- SECONDARY ANTIBIOTIC PROPHYLAXIS: before dental procedure, etc.; lack of evidence to reduce procedure-related bacteremia and distant site infection
What are the thoughts on bone pins, plates, and screw infections as the result of oral species?
- orthopedic hardware not within synovial joint not at increased risk for hematogenous seeding by microorganisms- caused by staph or other skin bacteria- external fixation especially prone to infection- guidelines consistent: no indication for antibiotic prophylaxis to prevent oral bacterial source for patient with pins, plates, and screws
What are the two types of Cerebrospinal fluid shunts? What are the thoughts on cerebrospinal fluid shunt infections as the result of oral species in each?
- VENTRICULO-PERITONEAL (VP): does not involve vascular structures so low bacteremia; high rate of infection with skin bacteria; prophylaxis not recommended- VENTRICULO-ATRIAL (VA): AHA 2003 said no evidence that microorganisms associated wth dental procedures cause infection of nonvalvular cardiac devices
Describe the relationship between periodontitis and diabetes.
- increased prevalence of periodontitis in diabetics- treatment of periodontitis improves glycemic control- hyperactive innate immune response antecedent of both diseases- diseases have synergistic effect on inflammation- may promote dyslipidemia leading to CVD
Describe the relationship between cardiovascular disease and oral bacteria and the evidence for causality.
- coronary heart disease, stroke, and peripheral vascular disease are all associated with periodontitis; association is modest; link but no causative relationship established- may have a common cause (inflammation) or bacterial toxins or seeding of bacteriaEVIDENCE:- perio treatment trials have shown favorable responses but have not shown reduction in CVD- P. gingivalis exacerbates CVD in animal models- P. gingivalis and other perio pathogens found in atherosclerotic lesions
Describe the relationship between periodontitis and pancreatic cancer.
- studies show increased risk of pancreatic cancer in patients with periodontitis- pancreatic cancer is also linked to smoking, obesity, type 2 diabetes, insulin resistance
What should be of concern if you have a patient with systemic lupus erythematosus?
half of SLE patients have cardiac involvement (mitral valve insufficiency); prophylaxis is indicated with valve replacement only!
What precautions should be taken to prevent direct transfer of infective agents (infective endocarditis, pneumonia in compromised airway, immunosuppression, preterm birth)?
- improve oral health- reduce bacterial load- antibiotic prophylaxis only in high risk situations
What precautions should be taken when there is a possible transfer of an agent, but a common pathway is most likely (type 2 diabetes, cardiovascular disease, pancreatic cancer)?
primary preventive strategy is to treat periodontal disease to improve microbial profile and improve overall health by addressing risk factors
What precautions should be taken to prevent oral effects on systemic disease with the following conditions?- cardiovascular implantable electronic devices (CIED)- vascular grafts/stents- intravascular access devices- prosthetic joints- bone pins, plates, and screws- renal dialysis shunts- cerebrospinal fluid (CSF) shunts- systemic lupus erythematosus
NO SPECIAL ORAL PRECAUTIONS! (not oral bacteria)
Describe the dynamic balance of demineralization and remineralization.
- lactic acid produced by bacteria dissolves mineral from enamel- salivary minerals are deposited in enamel- no net change occurs
Describe the pathophysiology of caries progression.
- bacteria produces lactic acid from glycolysis of sugars- lactic acid drops pH and mineral matrix of tooth dissolves- tooth surface is stabilized by pellicle proteins so initial demineralization is subsurface (thin shell of enamel overlying body of lesion)- cavitation when subsurface demineralization becomes too severe or extraordinary force applied- remineralization possible as long as surface is retained
Is remineralized tooth structure or virgin enamel stronger? Why?
- remineralized tooth structure- incorporation of fluoride into hydroxyapatite crystal structure
What bacteria are involved in caries initiation?
- Streptococcus mutans- other Strep., S. sobrinus, S. salivarius- Veillonella metabolizes lactic acid- Actinomyces?
What bacteria are involved in caries progression?
- S. mutans- Lactobacillus casei, rhamnosus, gasseri, fermentum- Bifidobacterium & Scardovia
What type of bacteria is the most common supragingival organisms? Name each of them.
StreptococcusS. mutans (mutans streptococci)S. sobrinus (mutans streptococci)S. sanguinis (mitis group, including those below)S. parasanguinisS. mitisS. pneumoniaeS. gordoniiS. salivarius
Is S. mutans gram positive or negative? What shape? What type of respiration? What is its nutrition?
- gram-positive- cocci- facultative- ferments carbohydrate (only nutrient source)
Describe S. mutans biofilm behavior. Explain how it adapts for feast or famine.
- biofilm behavior: attaches to S. sanguinis; elaboration of extracellular polysaccharide matrix- feast: active transport ans self-protection by excretion of lactate- famine: good scavenger; good storage mechanisms; can maintain energy source (and low pH) over a long period of time
How can the environment affect S. mutans? What is the advantage of S. mutans to the host?
- fluoride interferes with transport and intracellular processes; pH dependent (activated at low pH)- advantage to host: protective against beta-hemolytic or other pathogenic strep (lactate and bacterocins)
What are the similarities and differences between S. mutans and S. sobrinus?
- similarities: closely related to S. mutans (collectively termed “mutans streptococci”); strongly associated with caries- differences: usually found in lower numbers than S. mutans
Describe S. mitis.
- ubiquitous- earliest acquired oral bacteria- bound by salivary amylase- not cariogenic
Where is S. sanguinis found? Gram positive or negative? What shape? What type of respiration?
- found in healthy (noncariogenic) plaque- gram-positive- cocci- facultative
How does S. sanguinis colonize? Describe its metabolism.
- good initial colonizer of pellicle-coated tooth surface; attaches via adhesins; adheres well- ferments carbohydrate and proteins; produces lactic acid well at high pH; can survive without sugar (ariginine hydrolase pathway raises pH (arginine -> urea -> NH3))
What bacteria is often a cause of infective endocarditis?
S. sanguis
Where can S. salivarius be found? Is it associated with caries? Is it found in saliva? What can it do?
- tongue and tooth are both niches- has been associated with caries- detected in saliva but doesn’t grow there- excludes S. pyogenes
What effects does fluoride have on S. mutans?
- blocks active transport- blocks enolase (used to release lactic acid)
What type of caries can Actinomyces contribute to? Gram positive or negative? What shape? Respiration? Metabolism?
- root caries or early stages of enamel caries- gram-positive- filamentous- anaerobic or facultative- saccharolytic; acidogenic
Describe the metabolism of Veillonella. What is its contribution to the biofilm? Gram positive or negative? Respiration?
- does NOT ferment carbohydrates; ferments lactate -> propionate, etc -> raises pH!- protects against acid or helps acidogenic community members survive and contributes to caries- gram-negative- anaerobic
What are the different species of Lactobacilli? Where are Lactobacilli important? Gram positive or negative? Shape? Respiration? Metabolism?
- casei, rhamnosus, gasseri, fermentum- important in established or deep lesions- gram-positive- rod- anaerobic- saccharolytic; acidogenic; extremely acid tolerant
Where are Bifidobacterium and Scardovia important? Gram positive or negative? Shape? Respiration? Metabolism?
- may be important in deep caries- gram-positive- pleomorphic rods- anaerobic- saccharolytic and acidogenic and acid tolerant
Describe the attachment of S. sanguinis and S. mutans and development of biofilm.
- S. sanguinis binds to pellicle via specific adhesins- S. mutans binds to S. sanguinis via specific adhesins- S. mutans elaborates extracellular matrix from available sucrose (cross-linked insoluble polysaccharide = glucan)- S. mutans attaches glucan via glucan-binding proteins- both organisms can divide and stick, plus provide sites for attachment of other species
Describe the mechanism through which extracellular matrix is made.
sugar binds to glycosyl transferase site; monosaccharide is sent into the cell while the rest is bound to a glucan binding site on the cell surface