Antimicrobial Medications Flashcards
Use of a drug to prevent imminent infection of a person at risk.
Prophylaxis
what did Alexander Flemming identify mold as?
Penicillium
Substances produced by natural metabolic processes of some microorganisms that can destroy other microorganisms
Antibiotics
what is the primary goal of antimicrobial
chemotherapy?
administer drug to infected person, destroying the infective agent without harming host’s cells
Features of Antimicrobial Drugs
- Drugs differ in how they are what?
-Important factor for consideration when prescribing - The rate of elimination of drug from body is expressed in?
– Time it takes for the body to eliminate one half the original dose in serum
– dictates frequency of dosage - T or F: Patients with liver or kidney damage tend to excrete drugs more quickly?
- distributed, metabolized and excreted
- half-life
- False, they excrete drugs more slowly
If antimicrobials are effective against a LIMITED array of microbial types this is known as what?
Is this effective against gram + or -?
Narrow spectrum
can be effective against gram + OR - not both
Antimicrobials effective against a wide variety of microbial types
Is this effective against gram + or -?
broad spectrum
can be affective against BOTH gram+ and -
Who successfully purified penicillin?
What were they awarded with?
Ernst Chain and Howard Florey
Noble prize in Physiology in medicine with Fleming (1945)
Where do most modern antibiotics come from?
organisms living in the soil (bacterial species & fungi)
When drugs are chemically altered to impart new characteristics what is this termed?
semi-synthetic drugs
Antibiotics are classified by their what?
Mechanism of action
What are 4 adverse effects of antimicrobial drugs?
- Allergic reactions (penicilin)
- Toxic effects (aplastic anemia)
- Suppression of normal flora (colitis)
- antimicrobial resistance
Antimicrobials that interfere
with the synthesis of cell wall
do not interfere with eukaryotic
cell. Why is this?
Animal cells lack a cell wall and plant cell do not.
- Why is Gram (-) resistant to Vancomycin?
- _____________
– Interferes with transport of PTG precursors across cytoplasmic membrane
– Toxicity limits use to topical applications
– Common ingredient in non-prescription first-aid ointments
- Does not cross lipid membrane of Gram (-)
- Bacitracin
Define high therapeutic index and give 3 examples
low toxicity with high effectiveness
- β lactam drugs
- Vancomycin
- Bacitracin
- _________________
* e.g. Gentamicin,
streptomycin
* Side effects with extended use include Nephrotoxicity - ________________
* Effective against certain Gram (+) and Gram (-)
- nephrotoxicity & teeth discoloration
* e.g. doxycycline has longer
half-life
–Allows for less frequent dosing
- Aminoglycosides
- Tetracyclines
What do Penicillins and Cephalosporins inhibit?
function of enzymes that help form peptide bridge
between glycan molecules
T/F Some microbes are resistant to drugs through production of β-lactamase enzyme
TRUE
Newer group, broad spectrum
Currently account for a majority of all antibiotics administered
These are resistant to most β
lactamases/penicillinases
these are charteristics of?
Cephalosporins
What 4 drugs are responsible for inhibiting protein synthesis?
- Aminoglycosides
- Tetracyclins
- Macrolids
- Chloramphenicol
- Two antibacterial drugs that inhibit
nucleic acid synthesis? - Two types of Fluoroquinolones
- Rifamycins can be used against what?
- Fluoroquinolones and Rifamycins
- Ciprofloxacin and Moxifloxacin
- Mycobacterium
3 types of macrolids?
1.erythromycin
2. clarithromycin
3. azithromycin
Which drug is generally used as drug of last resort for life
threatening infections?
Chloramphenicol
What is a lethal side effect of Chloramphenicol?
aplastic anemia
- Antibacterial Drug that
alters the cell membrane? - Polymyxin B Binds membrane of Gram (-) or (+) cells?
- Polymyxin B Limits use to what and why?
- Polymyxin B
- Binds membrane of Gram (-) cells
- topical application since it
can also bind to Eukaryotic cells
T/F Humans can make their
own folic acid
FALSE, they CANNOT make their own folic acid, it must come from the diet
Why is susceptibility only tested with pure cultures and not mixed cultures?
Because you cannot tell in a mixed culture if it is the pathogen or contaminant causing infection
- the smallest amount of an agent needed to inhibit growth of a microorganism?
- What technique is used for MIC?
- minimum inhibitory concentration (MIC)
- Tube Dilution
In a Kirby-Bauer Disc Diffusion Test, the inoculum density is standardized using what standard?
McFarland Standard
The Kirby-Bauer Disc Diffusion Test is used for what?
to qualitatively determine
susceptibility
- An adaptive response in which microorganisms begin to tolerate an amount of drug that would ordinarily be inhibitory?
- Microbes become newly resistant to a drug after either? (2 things)
- Drug resistance
- Spontaneous mutations or Acquisition of new genes via plasmids
What represents susceptibility in Kirby-Bauer Disc Diffusion Test
Clear zone of inhibition around disc
T/F The E test uses strips impregnated with gradient concentration of antibiotic
-From highest concentration to lowest
TRUE
Every time you take a drug what happens in your system?
Drug resistance begins to develop and can dominate the population.
Give 3 bacteria examples of emerging antimicrobial resistance
- Staphylococcus aureus
- Mycobacterium tuberculosis
- Enterococci
fill in the blank w/ emerging antimicrobial resistance
____________: common causes of nosocomial infections
____________: Part of normal intestinal flora
_____________: Organism is acid-fast,
- Staphylococcus aureus & Enterococci
- Enterococci
- Mycobacterium tuberculosis
Polyenes and Azoles are drugs that do what?
target ergosterol
A fungal infection is caused
by a ______________, it is very hard to kill
these organisms and not harm your cells
eukaryote
Failure of antimicrobial treatment could be due to what 3 things?
inability of the drug to diffuse
resistant cells in the culture
infection caused by more than one
pathogen
T/F Antimicrobials can alter
your normal flora
If so, explain why?
TRUE
broad-spectrum antimicrobial will destroy infectious agents but also beneficial species
Bacteriophage therapy
New way of treating superbug infections
