Ch7 Antiinfective Agents Flashcards
Caries are produced by
Streptococcus mutans
Are antibiotics useful to treat or prevent caries?
No
After pain management, what is the dental problem for which drugs are most often prescribed
Infection
Dental Infections can be divided into several types including:
Caries
Periodontal disease
localized dental infections
systemic infections
what is the biggest dental problem in the adult patient
periodontal disease
Organisms initially responsible for a dental infection are primarily
gram positive cocci
After a short time, the gram positive infection begins to include a variety of both gram positive and negative anaerobic organisms this is termed a?
mixed infection
Over time the proportion of organisms that are anaerobic increases until it consists of predominantly
anaerobic flora
The choice of antibiotics for an infection depends on
where it is in its evolution.
If the infection is just beginning the organisms are most likely
Gram positive cocci
What is the drug of choice for infection?
*unless pt is allergic to it
penicillin (Pen VK)
A pt allergic to penicillin what alternatives ay be used to treat infection
clindamycin or erythromycin
What antibiotic would be the most effective to use during the mixed infection stage?
Clindamycin (affects both gram positive and negative anaerobes)
Some DDS avoid the use of clindamycin because of the association of
pseudomembranous colitis
Antibiotics are chemical substances produced by? they have the capacity to do what?
Microorganisms that have the capacity (in dilute solutions) to destroy or suppress growth of organisms
the ability to kill bacteria; effect is irreversible.
Bactericidal
Ability to inhibit or retard the multiplication or growth of bacteria; reversible
bacteriostatic
concentration of the anti-infective agent present in the blood or serum refers to
blood serum level
what is the nonhomeostatic multiplication of organisms within the body is
infection
does the presence of a pathogen constitute “invasion”?
no
Describe minimal inhibitory concentration (MIC)
lowest concentration needed to inhibit growth of an organism on media after 18-24 hours of incubation
superinfection/suprainfection describes
infection caused by proliferation of MO’s different from those causing the original infection
Superinfection is more often caused by ____ antibiotics and increases when taken for a ___ time period
broad spectrum antibiotics; longer
the pathogenic organisms emerging in a superinfection generally are
more difficult to eradicate than original organism and more likely to exhibit resistance
Most superinfections are caused by what kind of bacteria
staph or strep
what does synergism refer to
when the combo of 2 antibiotics produce more effect than would be expected if their individual effects were added.
when a combo of 2 agents produces less effect than either agent alone this describes
antagonism
Factors that determine the likelihood of a MO causing an infection (3)
- virulence
- inoculum (#of organisms present)
- resistance of the host (immunologic response)
host resistance should be considered as having both
local and systemic components
drugs such as ___ are capable of reducing a patients immunity
steroids
Diseases such as AIDS and IDDM may reduce what? increase what?
reduce pt immunity
increase chance of infection
culturing involves
growing the bacteria
sensitivity involves
exposing the organism to test antibiotics and determining whether the organism is sensitive or resistant
culture and sensitivity is the only way to be sure a drug will
kill or inhibit the growth of the infecting MO
Culture & sensitivity: an antibiotic disk with a zone around it shows
sensitivity
how many days are required before the results of the culture and sensitivity test are available
1-2 days
Can antibiotic therapy be initiated before the results of the culture/sensitivity test are available
YES
Natural or acquired ability of an organism to be immune to or to resist the effects of an antiinfective agent
Resistance
Bacterial resistance can occur by the transfer of
DNA genetic material from one organism to another via transduction, transformation, or bacterial conjugation
what occurs when an organism has always been resistant to an antimicrobial agent
natural resistance
what occurs when an organism that was previously sensitive to an antimicrobial agent develops resistance
acquired resistance
an increase in the use of an antibiotic in a given population increases the
proportion of resistant organisms in that population
the transfer of genetic material from one organism to another may occur among
very different microorganisms
2 categories of the need for antimicrobial agents include
therapeutic and prophylactic
Most patients, without immune function deficiencies, in whom drainage can be obtained do not need
antibiotics to manage dental infections
what is usually NOT treated with antimicrobials
adult periodontitis
