Microbiology Flashcards
The most useful microbiological staining techniques which separates bacterial organisms into two groups based on their cell wall structures
Gram stain
Stains blue
gram +
Stains red
Gram -
Gram + cell wall structure
Thick 2 layers No porin channel No periplasmic space Susceptible to breakdown by penicillins and lysozyme No endotoxin
Gram - cell wall structure
Thin 3 layers porin channel periplasmic space not susceptible to breakdown by penicillins and lysozyme Endotoxin (outer membrane)
Acid fast technique is used for
mycobacterium tuberculosis (TB)
Syphilis (treponema pallidum) and lyme disease ( Borrelia burgdorferi) are caused by what type of bacteria
Spirochetes
These spirochetes are associated with NUP and NUG
Treponema denticola
Spirochetes require this to identify them
dark field microscopy
Spherical organisms
Coccus (cocci)
Rod like structures
bacillus (bacilli) sometimes referred to as rods
lacking distinct shape
pleiomorphic
spiral shaped bacteria
spirochete
The most commonly used source of energy and carbon for humans and bacteria is
glucose
What are the 3 enzymes bacteria posses to break down oxygen products
catalase
peroxidase
superoxide dismutase
Catalase
breaks down hydrogen peroxide
Peroxidase
breaks down hydrogen peroxide
Superoxide dismutase
breaks down superoxide radical
what are the bacterial categories
obligate aerobes
facultative anaerobes
microaerophilic
obligate anaerobes
Uses the krebs cycle and glycolysis
Must have oxygen to survive
Obligate aerobes
Facultative anaerobes
Aerobic
Use oxygen
CAN grow in the abscence of oxygen by using fermentation
MOST DISEASE CAUSING ORGANISMS*
Microaerophilic bacteria
Aerotolerant anaerobes
uses fermentation
can tolerate low amounts of oxygen because they superoxide dismutase
Cannot tolerate oxygen
Can live in periodontal pockets and sulcus *
obligate anarobes
Lag phase
Growth is SLOW as first
Cellular metabolic activity was NOT increased `
Logarithimic (exponential) phase
Growth occurs very rapidly
Phase that microorganisms are most prone to breakdown by antimicrobial agents
Stationary phase
No net increase or decrease in cell numbers as nutrients are used up and waste products build up
After the stationary phase ends, microbes die off
death phase
How are gram + streptococcus arranged
chains or pairs
Streptococcus
microaerophilic
non-mobile
All organisms are catalase negative
What are the 3 groups of streptococcus
Beta hemolytic streptococcus
alpha hemolytic streptococcus
gamma hemolytic streptococcus
Completely lyse a RBCs
beta hemolytic streptococcus
partially lyse RBCs
alpha hemolytic streptococcus
Gamma hemolytic streptococcus
unable to lyse RBCs
How are beta hemolytic streptococcus arranged
in groups A-U known as lancefield groups
Group A streptococcus (GAS) or Streptococcus pyogenes
facultative, gram + cocci
grows in chains
highly communicable and primarily spread through person-to-person contact
Causes pharyngitis (strep throat), tonsillitis, scarlet fever, and cellulitis
Group A streptococcus or streptococcus pyogenes
Organism produces greenish tint when cultured
Viridans group of streptococcus
Normal inhabitants of the nasopharynx and gingival crevices
Viridans group of streptococcus
Viridans group of streptococcus causes 3 main types of infections
dental infections (caries) endocarditis abscesses
Causative for the majority of endocarditis cases
Streptococcus mitis
Streptococcus mutans
Viridans
Causative for dental caries
Ability to synthesize glucans from sucrose
Aciduric and acid producing
Group A streptococcus (GAS)
Causative for pharyngitis (strep throat) and scarlet and rheumatic fever
Streptococcus pyogenes
Streptococcus sobrinus
Viridans
Associated with dental caries
Streptococcus mitis
Viridans
Implicated in bacterial endocarditis
Streptococcus sanguinis
Viridans
early plaque colonizer
implicated in bacterial endocarditis and dental caries
Principal commensal bacterium of the oral cavity
one of the first microbes to colonize an infants mouth
associated with the tongue*
Streptococcus salivarius
Causative for pneumonia
Can be encapsulated with a polysaccharide layer makes it very resistant
Streptococcus pneumoniae
Generally harmless component of normal flora
Has powerful arsenal of enzymatic and exotoxin weapons
staphylococcus
Important characteristics of staphylococcus
Spherical gram + cocci arranged in grapelike clusters
Facultative anaerobe
Typical lesion of a staphlycoccus is abscess formation
Major producer of proteins called leukocidins (destroy phagocytes); destroyed phagocytes make up much of the material of pus
Staphlycoccus aureus
What is the most resistant disease causing organism and the treatment
MRSA (staphylococcus aureus)
TX; vancomycin and bactrim
Causative agent of actinomycosis
Common clinical form is lumpy jaw
Actinomyces
Prevotella
Gram - rod
obligate anaerobe
Main pathogenic bacteria in pregnancy related gingivitis
Can also be isolated from pericoronitis
Implicated in NUP/NUG
Prevotella intermedia
Porphyromonas gingivalis
MAJOR player in periodontal diseases
Possesses surface fimbrae
Produces collagenase
Neisseria
Colonizes the mucosal surfaces
Only 2 are are pathogens; Neisseria meningitides (meningitis) and Neisseria gonorrhoeae (gonorrhea)
Causative for lyme disease (Borrelia burgdorferi) and syphilis (treponema palladium) Treponema denticola (NUP/NUG)
Spirochetes
Gram +, aerobic, acid fast bacteria occuring as slightly curved or straight rods
mycobacterium
Stimulated by the presence of female sex hormones
Implicated in pregnancy gingivitis
Camphylobacter
Systemic infection of candida may involve
Lungs
Kidneys
Heart
Esophagus*
Topical treatment of fungal infections
Nystatin and clotrimazole
Systemic treatment of fungal infections
Ketoconazole and fluconazole (Diflucan)
Unique characteristics of viruses
Must have host cell
Composed of protein core (capsid)
May have outer lipid bilayer (envelope)
Small
What is a complete virus called
virion
How are viruses shaped
Helical or icosahedral (20 faces)
Function of mRNA
Translation
What is transcription
DNA to RNA
Examples of RNA viruses
Hep A,C,D,E* Influenza virus Mumps Measles HIV*
Examples of DNA viruses
Hep B HPV Hepes I and II Varicella zoster Epstein barr virus
What is an intact Hep B virus called
Dane particle
Anti-HBsAg=
No active disease, immune
HBeAg=
High infectivity and active infection
Example of artifical acquired active immunity
hep b vaccine
example of passive immunity
gamma globulin
Linked to oropharyngeal malignancy
HPV 16 and possibly HPV 18
Gardasil
HPV and there is a vaccination available
Varicella zoster virus
Epstein barr virus
Kaposi’s sarcoma
Herpes viruses
Varicella zoster virus
Causes chickenpox and herpes zoster (shingles) upon reactivation of the dormant virus
Causative organism for infectious mononucleosis and may also be implicated in malignancies such as nasopharyngeal carcinoma and Burkitts lymphoma
Ebstein Barr virus
Implicated in oral hairy leukoplakia
EBV
Kaposi sarcoma herpesvirus
Associated with AIDS
Coxsackie virus
Causative organism for herpangina (NOT herpes virus)
What are the characteristics of antigens
Foreigness (non-self) High molecular weight Chemical structural complexity Antigenic determinants (epitopes) Dosage, route, and timing of exposure
Cells of the immune system
Made up of leukocytes that are produced in the bone marrow Granulocytes Lymphocytes Monocytes Dendritic cells
Granulocytes
neutrophils, eosinophils, basophils
lymphocytes
t cells, b cells, natural killer cells
monocytes
precursor to macrophages
dendritic cells
antigen presenting cells; APCs
Characteristics of the innate immune system
present from birth
acute inflammation
dominant system of defense in most organisms
no memory
Acute inflammation
A vascular response characterized by edema, redness and pain
Nonspecific defenses include
Neutrophils
complement system
phagocytosis
fever
Most numerous of the white blood cells
Neutrophils (polymorphonucleocyte)
Neutrophils
First line defenders
phagocytes
Relaease powerful enzymes and cytokines
When something is wrong with neutrophil functions
periodontal diseases results
3 main functions of macrophages
phagocytosis
cytokine production
As an antigen presenting cell, macrophages transport, process, and present antigens
Group of white blood cells that destroy tumor cells and virally infected cells
Natural killer cells
Natural killer cells
non-specific killers
not phagocytes
kill without antibody
active without prior exposure to antigen
Common at sites att he body that are exposed to the external environment and are found in close proximity to blood vessels
Mast cells
What happens when mast cells release histamine
capillaries dilate and vascular permeability is dramatically increased leading to edema
Two antibodies are capable of activating the complement system
IgG
IgM
When a cell becomes infected with a virus the host cell secretes a group of proteins called
interferons
Interferons
stimulate healthy cells to produce proteins that interfere with the synthesis of viral proteins
What causes a fever
pyrogens
Cellular immunity
T-cells defense against infections (especially mycobacterium tuberculosis and fungal) delayed hypersensitivity graft and tumor rejection regulation of antibody response
Humoral immunity
B cells (plasma cells) defense against infection (opsonizes bacteria) allergic response autoimmunity
remember pathogens for faster antibody production
B memory cells
Types of antibodies
IgG IgM IgM IgE IgD IgA
Most adundant ig
only AB to cross the placental barrier
enhances phagocytosis (opsonizes)
complement activator
IgG
Main immunoglobulin in secretions (saliva)
Has j chain and secretory component
IgA
First AB made
most efficient in agglutination
complement activator
IgM
Most active Ab in response to allergens (bind to mast cells and basophils)
prime defense against parasites
IgE
Key antigen presenting cell
critical in initiating immune response
help to regulate adaptive immune responses
Dendritic cell
Classification used to describe immunoallergic hypersensitivity reactions
Gell coombs
Type I hypersensitivity reaction
anaphylactic reaction
type II hypersensitivity reaction
cytotoxic reaction
type IV hypersensitivity reaction
cell mediated or delayed reaction
type III hypersensitivity reaction
immune complex reaction
Allergic reaction that appears very quickly after exposure to previously encountered allergen
IgE is the primary antibody involved and causes release of histamine
Type I
T cells (not antibodies) are involved in this hypersensitivity reactions
T cells release cytokines which activate phagocytosis leading to tissue inflammation and injury
Ex) Mantoux skin test
Type IV cell mediated reaction
Antigens on a cell surface combine with antibody which leads to complement mediated lysis
EX) Rh and transfusion reactions
Type II cytotoxic reaction
Most likely antibiotic class to produce anaphylactic reaction
penicillins
The immune complexes are not cleared and persist in blood vessels, filtering organs, and synovial membranes (mechanism for autoimmune disorders)
Type III immune complex reaction
Scleroderma
autoimmune disorder that is associated with raynauds phenomenon and generalized widening of the PDL
Which antibody is the most abundant antibody in the body
IgG
Which type of heptatitis is a dental hygienist least likely to get
hep e
in plaque biofilm what makes up the bulk of the deposit
exopolysaccharides
which is the first antibody to be produced after birth
IgM
which antibody is involved in type I hypersensitivity
IgE
Which blood type can be given to all individuals
type O negative
microscopically, staphylococci present as
grape like clusters
These organisms are implicated in pregnancy gingivits
prevotella intermedia
which of the following organisms is causative for pharyngitis (strep throat) ad scarlet fever
streptococcus pyogenes
which type of bacteria is most often implicated in root caries
actinomyces
which microorganism can be encapsulated with a polysaccharide layer
streptococcus pneumoniae
the complement system aids in the immune response by
increasing lysis and opsonization
which microscopic technique muct be employed to identify mycobacterium tuberculosis
acid fast staining
at what stage of bacterial growth are organisms most susceptible to antimicrobial action
log phase
which bacteria is an early colonizer that is associated with the tongue
streptococcus salivarius
