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150 Cards in this Set

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Dental infections can be divided into several types as follows:
Caries, periodontal disease, localized dental infections and systemic infections
Most dental infections are initially due to these organsisms?
Gram-positive cocci, like Streptococcus viridans, or alpha-hemolytic streptococci
Initial gram-positive infections often change to include both gram-positive organisms and _____-______ _______ organisms
Gram-negative anaerobic
Over time dental infections progress to include almost nothing but ________ organisms
Anaerobic
Initial dental infections are usually treated with ______ or ________
Penicillin or ampicillin
If someone is allergic to penicillin an alternative antibiotic would be ______ or _________
Erythromycin or clindamycin
If an anaerobic infection is suspected one should add __________
Metronidazole (Flagyl)
Clindamycin is effective against these organisms but may lead to ________ ________
Gram-positive cocci and gram-positive/negative anaerobes. Pseudomembranous colitis
The antibiotic Prontosil was found to protect mice from infection by streptococci in ____.
1932
In ______, Fleming found that the mold Penicillium notatum, inhibited bacterial growth
1928
Substances from any source that act against or destroy organisms that cause infections
Antiinfective agents
Substances from any source that destroy or suppress the growth or multiplication of bacteria
Antibacterial agents
Chemical substances made by microorganisms that can destroy or suppress the growth of organisms
Antibiotic agents
Substances that destroy or suppress the growth or multiplication of microorganisms
Antimicrobial agents
Substances that destroy or suppress the growth or multiplication of fungi
Antifungal agents
Substances that destroy or suppress the growth or multiplication of viruses
Antiviral agents
The ability to kill bacteria even if bacteria removed from drug after exposure
Bactericidal
The ability to inhibit or retard the multiplication or growth of bacteria that is reversible if bacteria removed from the drug
Bateriostatic
Concentration of the antiinfective agent in the blood
Blood (serum) level
Invasion of the body by microorganisms and tissue reaction to their presence
Infection
Lowest concentration of drug needed to inhibit visible growth of an organism in media after 18-24 hours of incubation
MIC (minimum inhibitory concentration)
Range of activity of a drug against various microorganisms
Spectrum
Infection caused by the proliferation of organisms different from what caused the original infection
Superinfection
A combination of two antibiotics produces more effect than either would alone
Synergism
A combination of two antibiotics produces less effect than either agent alone
Antagonism
Infection factors:
Virulence, Inoculum, Resistance of the host
Growing bacteria on a media from a sample of infective exudate.
Culturing
Exposing organisms to certain antibiotics to test sensitivity or resistance of organism to antibiotics
Sensitivity testing
Why is it difficult to get good information from dental cultures?
Anaerobic bacteria difficult to culture and many infections are mixed making interpretation of culture difficult
How do we obtain cultures from dental patients?
aspiration with a needle, a swab, or absorbent points
Care must be taken when culturing patients to not contaminate the sample with ____________
Supragingival plaque
How many days does it usually take to get sensitivity results from cultures
1-3 days
The natural or acquired ability of an organism to be immune or resist the effects of an antiinfective agent
Resistance
When an organism has always been resistant to an antimicrobial agent because of the bacteria's normal properties
Natural resistance
An organism that was previously sensitive to an antimicrobial agent develops resistance
Acquired resistance
How does resistance develop in microorganisms?
Spontaneous mutations, increase in antibiotic use, or transfer of DNA from one organism to another via transduction, transformation, or bacterial conjugation
What changes tend to occur in bacteria that causes acquired resistance?
A decrease in bacterial permeability, production of bacterial enzymes, and an alteration in the target site for the antibiotic
The best defense against a pathogen is the _____ _______
Host response
What type of infection should be treated with an antibiotic?
Acute, severe, rapidly spreading infection
What type of infection may not need treatment?
Mild, localized infection where drainage is obtained
When is prophylactic antibiotic therapy recommended?
With history of infective endocarditis, valve prosthesis, or congenital heart disease
If an antibiotic kills off some organisms allowing the overgrowth of others this is called a _______________
Superinfection
What antibiotics tend to be the most allergenic?
Penicillins and cephalosporins
If a woman of child-bearing age is taking these antibiotics and oral contraceptives the contraceptives may fail.
Ampicillin and tetracycline
What antibiotics may prolong the INR of a patient?
Tetracycline and erythromycin
These two antibiotics work on the same receptor so should not be given together.
Erythromycin and clindamycin
These two classes of antibiotics should not be given together
Bacteriostatics and bactericidal
What antibiotic has the highest incidence of GI side effects
Erythromycin
What antibiotics can generally be used in pregnant patients?
Penicillin and erythromycin
An important factor to consider in prescribing antibiotics is the patients ___________ status
Socioeconomic status
Name the four major Penicillin groups.
Penicillin G&V, Penicillinase Resistant, Ampicillins, and Extended Spectrum
What mold naturally produces penicillin
Penicillium notatum
Penicillin contains this type of "ring" that can be broken by penicillinase enzyme secreted by bacteria rendering the drug ineffective
Beta-lactam
What route of administration should NOT be used for penicillins?
Topical because allergies are more likely with this route
The half-life of penicllin G and V is __________
30 minutes
Penicillin works by binding to these proteins on the bacterial cell membrane
PBPs (penicillin-binding proteins)
Penicllin works by inhibiting the formation of ________
Cross-linkages that form the cell wall of the bacteria
Penicllin is effective against many of the microbes responsible for _______ infections
Periodontal
Toxicity with penicillin's is _____________ (likely or unlikely)
Unlikely
What percent of patients getting penicillin will have some type of reaction?
5 - 10%
Name four types of allergic reactions to penicillins
Anaphylaxis, Rash, Delayed serum sickness, and oral lesions
What percent of patients receiving penicillin develop an anaphylactic reaction?
0.05%
If patients are allergic to penicillins what are two other drugs that may be used for oral infections?
Erythromycin or Clindamycin
What type of penicillin G should be avoided in cardiac patients?
Sodium penicillin G
What are the two drugs of choice in treating a penicillinase secreting bacteria?
Cloxacillin and dicloxacillin
The drug of choice for prophylaxis for bacterial endocarditis prior to a dental procedure is ___________
Amoxicillin
The enzyme penicillinase can be blocked by adding this drug to amoxicillin
Clavulanic acid
An extended-spectrum penicillin that is effective against Pseudomonas aeruginosa and some strains of Proteus is ____________
Carbenicillin
Name the three macrolide antibiotics
Erythromycin, charithromycin and azithromycin
Is erythromycin bacteriostatic or bactericidal
Bacteriostatic
In addition to treating Gm+ infections due to Staph. and Strept., erythromycin is also effective against these organisms
Bordetella, Legionella, Actinomyces, Mycoplasma pneumoniae, Entamoeba histolytica, and some Chlamydia species
The main side effect with erythromycin is _______
GI upset, stomatitis, abdominal cramps, N/V, and diarrhea
Erythromycin may increase the blood levels (toxicity) of these drugs
Theophylline, digoxin, triazolam, warfarin, carbamazepine, and cyclosporine
This is the drug of choice to use in penicillin allergic patients
Erythromycin
Two newer macrolide antibiotics like erythromycin are ______ & _______
Azithromycin (Zithromax, A-Pak) & Clarithromycin (Biaxin)
Azithromycin and Clarithromycin are effective against these bacteria
Aerobic Gram+ cocci and aerobic Gram - bacteria
This broad-spectrum antibiotic may also have adverse effects on developing teeth
Tetracycline
What bacteria were the early tetracyclines isolated from
Streptomyces
Tetracyclines are stored in the _____ and ______ of unerupted teeth and concentrated in the ____ _____ fluid
Dentine, enamel, gingival crevicular fluid
Are tetracyclines bacteriostatic or bactericidal
Bactriostatic
Tetracyclines work by bining to this subunit of bacterial ribosomes inhibiting protein synthesis
30S
Resistance to tetracyline is caused by this mechanism
Decreased uptake of tetracycliine by the organism
Are S. viridans and S. aureus resistant to tetracycline?
3/5th of S. viridans and 2/5ths of S. aureus are resistant to tetracycline
Most common reaction to tetracyclines is ____________
Gastrointestinal effects
Diarrhea in a patient taking tetracycline may be due to one of these three causes
Staphylococcal enterocolitis, intestinal candidiasis, or pseudomembranous colitis
Due to effects on teeth tetracyclines should not be used in these patients
Last 1/2 of pregnancy or children under 9 years old
Name some other adverse effects of tetracyclines
Hepatotoxicity, nephrotoxicity, hematologic effects, superinfection, photosensitivity, CNS and rarely allergic reactions
How do divalent and trivalent cations affect tetracycline absorption?
Form nonabsorbable chelates with dairy products, mineral supplements, antacids (Ca+2, Mg+2, Fe+2, Zn+2, and Al+3)
Name some other drug interactions with tetracyclines.
Enhanced blood levels of sulfonylureas, digoxin, lithium, theophylline, and warfarin.
Although not used often for dental infections, tetracyline can be used as plastic strips, hollow fibers, or collars placed into this area of the mouth.
Gingival crevice
Clindamycin is a bacteriostatic antibiotic primarily effective against these organisms
Gm+ organisms and anaerobic Bacteroides species
Clindamycin is effective against these anaerobic bacteria.
Bacteroides fragilis, Fusobacterium species, Peptostreptococcus and Peptococcus species, and Actinomyces israelii
Most common side effect of clindamycin is ___________
GI effects
Incidence of diarrhea with clindamycin is ____
10%
This disease is associated with overgrowth of Clostridium difficile while or after taking clindamycin
Pseudomembranous colitis
Is clindamycin the drug of choice for Gm+ organisms
No, other better ones are available which do not cause pseudomembranous colitis
The other name for metronidazole is ________
Flagyl
Metronidazole is effective against these organisms
Trichomonas vaginalis, Entamoeba histolytica, and obligate anaerobes such as the Bacteroides species
Is metronidazole bacteriostatic or bactericidal
Bactericidal
Like almost all the other antibiotics the most common side effect of metronidazole is __________ and it also can cause problems with these areas as well.
GI effects, CNS, Renal, Oral (dry mouth, metallic taste, glossitis, stomatitis, black-furred tongue), and Hematologic effects
Is metronidazole ok to give to a pregnant or nursing patient
Contraindicated in pregnancy due to teratogenicity and if given when nursing breast milk should be pumped and discarded while taking and 48 hours after stopping
Can one drink alchohol when taking metronidazole
No, it turns into an (Antabuse) like substance in the body
Metronidazole is especially useful in treating infections due to this type of bacteria
Anaerobes
One anaerobe that metronidazole will not treat is _________
A. actinomycetemcomitans
This group of antibiotics is similar to penicillins and is divided into 4 generations
Cephalosporins
Cephalosporins were isolated from this bacterium found in a sewer outlet near Sardinia, Italy
Cephalosporium acremonium
Although cephalosporins are resistant to penicillinase they may be broken down by this microbial enzyme
Cephalosporinase
The generation of cephalosporin indicates the width of antimicrobial action. The first-generation drugs are effective against ______ & few ________
Gm+ organisms, few Gm- organisms
By the third generations, cephalosporins work against these organisms
Few Gm+, many Gm- and anaerobes
Cephalosporins, like penicillins work by inhibiting ___________
Cell wall synthesis
Adverse reactions of cephalosporins
GI most common, nephrotoxicity, superinfection, localized reaction when used IM or IV: Some cause bleeding problems or produce a disulfiram (Antabuse) like reaction when given parenterally
Percent of hypersensitivity reactions in patients getting cephalosporins
5%
Cross-hypersensitivity may occur with cephalosporins and ____________
Penicillins (10% incidence)
List uses of cephalosporins
Penicillinase producing Gm+ organisms, Gm- Klebsiella, dental prophylaxis in patients with "at risk" joints
Drug of choice for Stage 1 dental infection is:
PCN V 500mg q 6 hr until symptoms gone for 2-3 days. If allergy: Erythromycin or clindamycin
Stage 2 infection treatment:
PCN V with or without metronidazole or clindamycin
Stage 3 infection treatment
Metronidazole or clindamycin
Reasons antibiotic treatment may fail:
Patient compliance, ineffective antibiotic, poor debridement, drug did not reach the site of infection or host defenses inadequate
This antibiotic is made by Streptomyces orientalis, and is used to treat drug resistant Gm+ cocci
Vancomycin
Name four aminoglycoside antibiotics
Neomycin, Gentamicin, Tobramycin, Amikacin
Aminoglycosides are used primarily to treat ________ infections
Gm- aerobic
Major side effects of aminoglycosides include _______ & ________
Ototoxicity, Nephrotoxicity; Peak and trough drug levels must be measured to prevent high levels and toxicity to these drugs
This antibiotic is bacteriostatic, inhibits protein synthesis by acting on the 50S ribosomal unit and is active against many Gm+ and Gm- organisms, rickettsiae, Chlamydia, and Salmonella typhi
Chloramphenicol
Chloramphenicol is rarely used and is of no use in dentistry due to the serious blood problems such as :
aplastic anemia, agranulocytosis, hypoplastic anemia, and thrombocytopenia
Sulfonamide antibiotics work by inhibiting bacterial synthesis of __________
Folic acid
The most common adverse reaction to sulfonamides is ___________a/an
Allergic skin reaction
Sulfisoxazole, trimethoprim is used prophylactically in HIV patients to prevent __________
Pneumocystis carinii pneumonia
Sulfamethoxazole plus trimethoprim is called __________
Bactrim, Septra, or SMX-TMP
In Bactrim both drugs inhibit steps in the synthesis of ___________
Folic acid
Sulfamethoxazole-trimethoprim is indicated in the treatment of these disorders.
Urinary tract infections, Otitis media, some respiratory and GI infections and prophylaxis in HIV patients against P. carinii pneumonia
This drug is bacteriostatic against many common urinary tract pathogens, may cause brown discoloration of urine and is used to treat or prophylaxis against urinary tract infections
Nitrofurantoin (Macrodantin)
These agents are the first orally active agents against certain Pseudomonas species, antagonizes the A subunit of DNA gyrase which is needed to make DNA
Quinolones (Ciprofloxacin, Norfloxacin, etc. all end in "-floxacin")
Ciprofloxacin is used for these conditions:
Lower respiratory tract, skin, bone, joint, and urinary tract infections. Maybe periodonal disease
Why is TB (tuberculosis) difficult to treat?
TB patients often immunocompromised already, resistant TB strains, dormant periods, only bacteriostatic but toxic drugs available, poor patient compliance with long treatment period
What three drugs are used to treat TB and what is the treatment regimen?
Isoniazid and rifampin q day for 9-12 months, and pyrazinamid q day for 2 months
How long before a TB patient may become noninfective with treatment?
2-3 weeks
If you suspect a patient may have TB what should you do?
Contact patients Dr. and delay treatment until disease no infectious
What types of patients have an autosomal dominant trait that may cause them to metabolize isoniazid quickly?
Eskimos, Japanese are fast acetylators as well as 50% of blacks and whites
Isoniazid may cause CNS problems by depleting this vitamin.
Vitamin B6
Vitamin B6 is also known as __________ and is given along with isoniazid to prevent depletion of Vitamin B6
Pyridoxine
This drug is used along with isoniazid to prevent TB resistance and works by inhibiting DNA-dependent RNA polymerase
Rifampin
This TB drug will turn the body fluids (urine, tears, feces, saliva, and sweat) a red-orange color
Rifampin
This TB drug is given for 2 months along with INH and rifampin
Pyrazinamide
When other antiTB drugs cannot be used or resistance is encountered this drug is used
Ethambutol
A combination of an aminoglycoside (neomycin) and two polypeptide antibiotics (polymixin and bacitracin) is available as an OTC ointment called _________
Neosporin or triple antibiotic ointment
In the triple antibiotic ointment Neosporin the neomycin affects Gm ______ organisms and the other two affect Gm ______ organisms
Negative, positive`
This topical antibiotic is made by Pseudomonas fluorescens, is active against Strept. and Staph bacteria and is used for the topical treatment of impetigo
Mupirocin (Bactroban)
Prophylaxis for dental procedures involving __________ or _________ or _________ is required in patients having certain cardiac conditions.
Manipulation of gingival tissue or periapical region of the teeth or perforation of the oral mucosa
What cardiac conditions predispose patients to the highest risk of endocarditis following certain dental procedures
Prosthetic cardiac valve, previoius infective endocarditis, certain types of congenital heart disease
Patients who have had total joint replacements should have antibiotic prophylaxis for how long after the joint replacement
2 years