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87 Cards in this Set
- Front
- Back
Pathogens usually enter the host through a
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break in the skin
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Staphylococus are gram
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positive
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movement of Staphylococus are...
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nonmotile, nonspore forming faulatative
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Staphylococus produce the enzyme
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catalase.
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Staphylococus can ferment
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glucose or mannitol to produce acids.
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3 species of Staphylococus are..
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Staphylococus aureus (s. aureus)
Staphylococus epidermidus (s.epidermidus) Staphylococus saprphyticus (s. saprophyticus) |
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s. aureus is the most
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likely species to cause disease
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s. aureus always secretes...
may secrete.... |
oagulase and hemolysins
leukocidins, exfoliatin, enterotoxins, penicillinasem hyaluronidase, lipase |
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s. aureus may produce
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protein A
pyrogenic toxins |
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Protien A
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binds the Fc portion of IgG and alows the bacterium to evade phagocytosis
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s. aureus can cause 6 disesase
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staphylococcal scalded skin syndrome
boils, furuncle and carbuncles wound infections staphylococcal enteritis toxic shock syndrome osteomylitis |
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staphylococcal scalded skin syndrome
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red peeling skin
high fever seen mostly in infants and immunocompromised patients |
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boils furuncle and carbuncles
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abcess of the skin begins as a boil may spread to form furuncle and move deeper to form a carbuncle
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wound infections
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most common cause of nosocomial wound infections
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staphylococcal enteritis
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intestinal becomes necrotic due to enterotoxin release by s. aureus after surgery or antibiotic use
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toxic shock syndrome
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fever rash nausea vomitting diarrhea exfoliation of palms and soles by an exotoxin
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osteomylitis
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nome infection hard to treat without surgery
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s. epidermidis
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does not serete coagulase
causes very few diseases but may cause nosocomial infection of surgically implanted devices. May also cause sepsis in neonatal nurseries. |
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s. saprophyticus
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does not secrete coagulase
frequent cause of urinary tract infections in women age 16-30 |
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s. pyrogenes is gram...
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positive
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movement of s. pyrogenes
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non motile non spore forming cocci arranged in chains
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s. pyrogenes
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must be treated with anitbiotics to prevent late complications
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s. pyrogenes may cause
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necrotizing fascitis
inpetigo puerperal fever |
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necorotizing fascitis
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s. pyrogenes infects deep tissues and spreads rapidly along CT fascia.
secretes a protein that causes necrosis of surrounding cells and tissues |
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impetigo
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skin infection in which small cesicles burst to form amber cursty highly infective lesions.
usually self limiting but highly contagious |
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puerperal fever
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mirobe enters deep tissues via the uterus after child birth cuasing sepsis
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Pseudomonas aeruginosa (P. aeruginosa) characterisitics
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gram negative, non spore forming strictly aerobic motile rod
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P. aeruginosa extremely resistant to
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anitbiotics
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P. aeruginosa produces
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a green or blue green pifment and a grape like odor when frown on regular culture media
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P. aeruginosa is an
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opportunist.
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P. aeruginosa will cause disease in
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immunocompromized individuals
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P. aeruginosa causes
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severe antibiotic resistant urinary tract infections , pneumonia or sepsis
also skin and ear infections in person s who use hot tubs |
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P. aeruginosa produces
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leukocidins and several exotoxins including exotoxin A
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Leptospira characteristics
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highly motile obligately aerobic spirochetes
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Leptospira found
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in nonhuman vertabrate animals and will infect humans when they come into contact with their skin or urine
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Leptospira spreads
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through the bloodstream of the infected human damagin the kidneys the liver the CNS and the eyes
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Leptospira symptoms
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include fever chills muscle aches and photophobia
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Leptospira can also be a form of
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Weils disease, and fort bragg fever
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Leptospira is most common among
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slaughterhouse workers, livestock handelersm sewage workers
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Clostridium tetani (c. tetani) characteristics
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gram positive spore forming strictly anaerobic motile rods
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c. tetani found in
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soil, dust, and feces,. infects humans when these materials come in to contact with an open wound.
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c. tetani produces
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a neurotoxin that interfere with the relaxation of some muscles
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c. tetani can be cleared with
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antibiotics and a antitoxin.
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Clostridium perfiringens (c. perfringens) characteristics
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gram positive spore forming strictly anaerobic motile rods.
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c. perfringens causes
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gas gangrene
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c. perfringens found in
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soil dust and feces. Humans infected when conatminated soil comes into contact with an open wound.
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c. perfringens secretes
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exotoxins called lethal toxins. cause tissue destruction, cardiac damage, and are thought to produce a high fever.
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B. anthracis characteristics
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gram positive pspore forming encapsulated rod.
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B. anthracis produces
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an exotoxin and an enzyme that work together to interfere with the phagocyti abilites of host leukocytes.
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B. anthracis ususally found in
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sheep cattle and few other plant eating animasl. humans become infeted trhough the skin due to contact with the endospores carried by the infected animals. .
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B. anthracis causes the disease
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anthrax. which produces a cutaneous lesion called a malignant pustule. spreads rapidly through the body.
pulminary form is called wool sorters disease. |
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dermatophytoses
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a type of fungus that enters the body via the skin
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dermatophytoses is carried
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in dogs and cats
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dermatophytoses infectinos starts
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at a single point and spreads outward. Ringworm.
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dermatophytoses is typically called
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tinia;
tiniea pedis - foot tinea corporis - skin tinea capitis - scalp tinea unguium- nails |
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conjunctivitis
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inflammation of the cinjunctiva of the eye. with redness and pus like discharge. contagious.
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neonatal gonorrhea ophthalmia
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an extremely serious form of conjunctivitis that occurs in the eyes of newborn infants.
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inclusion conjunctivitis
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usually a mild ofrm of conjunctivitis acquired by newborns during passage through the birth canal.
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trachoma
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a severe form of conjunctivits that causes scarring of the cornea due to the abrasive action of scar tissue esewhere in and around the eye. Most common cause of blindness worldwide.
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Normal flora of the respiratory tract
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located in the upper respiratory tract deposited by incoming air. the lower respiratory tract of a healthy person contains no permanent normal flora
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streptococcus
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all are gram positive non motile cocci that form chains. Aerotolerant bacteria. catalase negative.
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streptococcus is the most
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important respiratory pathogen
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streptococcus has 3 types
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alpha hemolytic strep
beta hemolytic strep gamma hemolytic strep |
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alpha hemolytic strep
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called alpha hemolysis. RBCs are partially lysed. causes blood agar to turn a green or brown color. which are called viridans streptococci.
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beta hemolytic strep
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beta hemolysis - RBCs are completely lysed. causes blood agar to become clear
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gamma hemoyltic strep
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gamma hemolysis - RBCs are unaffected.
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Lancefield classification system
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a means of classifying the beta hemolytic and gamma hemolytic streptococci. (not alpha)
Using the alphabet to classify the type of C carbohydrate they produce. |
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The identification of the C carbohydrate can only occur if
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an acid has been added to the bacteria until the pH reaches about 2
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streptokinase
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and enzyme secreted by streptococci
dissolves blood clots |
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DNAse
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and enzyme secreted by streptococci
breaks down DNA |
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erythrogenic toxin
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and enzyme secreted by streptococci
cuases a reddish skin rash and a high fever |
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leukocidins
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and enzyme secreted by streptococci
kill host leukocytes |
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lethal toxin
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and enzyme secreted by streptococci
kills mice |
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hyaluronidase
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breaks down hyaluronic acid in host "spreading factor'
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streptococcal pharyngitis
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strep throat
infection of the throat and tonsils irritating to mucous membranes of the throat cause enlarged lumph nodes and elevated WBC count and fever often associated with epidemics |
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impetigo
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already discussed as a skin pathogen
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scarlet fever
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similar to streptococcal pharyngitis with reddish skin rash and high fever
associated with erythrogenic toxin |
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toxic shock like syndrome
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infection spreads rapidly produces symptoms similar to those of TSS
very high mortality rate |
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acute glomerulonephritis
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destruction of kidney tissue caused by immune response to s. pyogenes antigens
can lead to kidney failure |
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rheumatic fever
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damage to heart valves and joints due to immune response to s. pyogenes antigens
cardiac damage may be severe |
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subacute bacterial endoarditis (SBE)
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caused by viridans carieties and enterococci
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SBE caused by
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viridans varieties and enterococci in people with previously damaged heart valves
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SBE infects
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damaged eart valves and cuases further damage and especially damageing to the bicuspid valve
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SBE symptoms
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fever heart murmur anemia and enlarged spleen are common
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Dental caries caused by
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several species of streptococci
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Dental caries is contracted by
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when saliva and tooth enamael interact anaquired pellicle forms on the tooth surface
bacteria grow on the aquires pellicle forming thick crusts called plaque and eventually damage enamel |
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Dental caries is prevented by
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proper brushing and flossing
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