Antibiotics Flashcards
(43 cards)
what is empiric therapy
may be one or multiple agents to give sufficient coverage
an “educated guess”
samples are good but takes several days for results
routes of administration for antibiotics?
topical, oral, intramuscular, IV, intravitreal (into the eye), or combination
what is drug resistance
bacteria evolve mechanisms to survive antibiotics
can occur if antibiotics are overprescribed, not thoroughly finished
What is the difference between Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan layer and appears purple 2° retaining the stain
Gram-negative bacteria have a thin peptidoglycan layer and appears pink 2° being counterstained with safranin.
What role does peptidoglycan play in bacterial cells?
provides structural rigidity to the bacterial cell wall.
examples of diseases caused by gram-positive bacteria?
strep throat, staph infections
examples of diseases caused by gram-negative bacteria?
e. coli and salmonella
why are Gram-negative bacteria often more resistant to antibiotics?
Their outer membrane acts as a barrier that can make it difficult for antibiotics to penetrate.
What is the significance of lipopolysaccharides (LPS) in Gram-negative bacteria?
LPS can be toxic when released into the body, contributing to disease.
What is a bactericidal agent?
a type of antibiotic that kills bacteria directly.
What is a bacteriostatic agent?
an antibiotic that inhibits bacterial growth and reproduction but does not directly kill the bacteria.
How do bactericidal and bacteriostatic agents differ in their mechanism of action?
Bactericidal agents disrupt essential processes, leading to bacterial cell death, while bacteriostatic agents interfere with protein synthesis or other functions to prevent bacteria from multiplying.
When might a bacteriostatic agent be preferred over a bactericidal agent?
Bacteriostatic agents are often preferred in cases where the immune system can effectively clear the infection after bacterial growth is inhibited.
What are the classes of antibiotics affecting cell wall synthesis?
Examples: Penicillins (e.g., Amoxicillin), Cephalosporins (e.g., Cefazolin), Vancomycin
Action: Inhibit the formation of the bacterial cell wall, leading to cell lysis and death.
What are the classes of antibiotics affecting the cell membrane?
Examples: Polymyxins (e.g., Polymyxin B) ((antibiotics for gram-negative bacteria))
Action: Disrupt the integrity of the bacterial cell membrane, causing leakage of cellular contents and cell death.
What are the classes of antibiotics affecting protein synthesis?
Examples: Tetracyclines, Macrolides, Aminoglycosides
Action: Inhibit bacterial ribosomes, preventing protein synthesis, which is essential for bacterial growth and reproduction.
What are the classes of antibiotics affecting folate metabolism?
Examples: Sulfonamides (e.g., Bactrim)
Action: Inhibit the bacterial enzyme involved in folate synthesis, disrupting nucleic acid synthesis and bacterial growth.
What are the classes of antibiotics affecting bacterial DNA synthesis?
Examples: Fluoroquinolones (e.g., Ciprofloxacin)
Action: Inhibit DNA gyrase and topoisomerase IV, enzymes necessary for DNA replication, leading to bacterial cell death.
Type I Drug Allergy Reaction Symptoms (basic)
immediate
urticaria rash
angioedema
can be life threatening
discontinue immediately and seek emergency services - epi-pen
Type II Drug Allergy Reaction Symptoms (basic)
Cytotoxic - delayed by several days/weeks
hemolytic anemia=
Life threatening
discontinue drug - self resolves
Type III Drug Allergy Reaction Symptoms (basic)
autoimmune - 1-3 wks
serum sickness, vasculitis
arthritis/arthalgia
fever/malar rash
discontinue drug: prognosis is excellent and self-resolves
Type IV Drug Allergy Reaction Symptoms (basic)
cell mediated hypersensitivity
symptoms: contact dermatitis - rash
discontinue offending agent and can use steroids
what are key safety concerns for penicillins?
V site reactions (burning, phlebitis), CNS effects (headache, dizziness, confusion, seizures), blood dyscrasias, altered bacterial flora (risk of superinfections), severe allergic reactions (urticaria, anaphylaxis), and potential failure of oral contraceptives.
What are the characteristics of 1st Generation Cephalosporins?
Effective against gram (+) bacteria; relatively weak against gram (-) bacteria.
