Antibiotics part 1 Flashcards
Drugs of natural or synthetic origin that have the capacity to kill or to inhibit the growth of microorganisms.
Antibiotic
True or false: Antibacterial is synonymous with antibiotic.
True
General term for natural or synthetic compounds which at certain concentrations inhibit growth of, or kill, microorganisms. Collective term.
Antimicrobial
Use of antimicrobials to prevent infection, like prior to surgery or dental procedures.
Prophylactic
Initiation of treatment prior to determination of a firm diagnosis. Ex: Initiation of antibiotics for a patient based on symptoms alone.
Empiric
Treatment directed at a specific pathogen or organism.
Definitive
What are some examples of things that are virtually impenetrable barriers to antibiotics?
Biliary stones, fluid cysts, vegetations
Agents that inhibit bacterial replication without killing the organism. Most inhibit protein synthesis
Bacteriostatic
Drugs which cause death and disruption of the bacterial cell, including drugs that primarily act on the cell wall, cell membrane, or bacterial DNA.
Bacteriocidal.
Lowest concentration of agent to inhibit growth. Used to determine whether the organism is considered susceptible to that particular antibiotic.
Minimum Inhibitory Concentration (MIC)
True or false: MIC may differ with different sites of infection.
True
True or false: The goal is to pick the antibiotic with the lowest MIC.
FALSE
True or false: The goal is to prescribe the antibiotic with the most narrow spectrum based on type of infection and organism present.
True
T > MIC
Time-dependent. Beta lactams, clindamycin
Cmax/MIC
Concentration dependent. Aminoglycosides
AUC/MIC
Vancomycin, tetracyclines, azithromycin.
What are the 5 mechanisms of antimicrobial action?
- Inhibit cell wall synthesis
- Inhibit metabolite synthesis
- Inhibit DNA replication
- Inhibit RNA synthesis
- Inhibit protein synthesis
CAPES
Citrobacter, acinetobacter, pseudomonas, enterobacter, serratia
HNPEK
H. influenzae, Neisseria, Proteus, E.coli, Klebsiella
CAPES and HNPEK are what type of bacteria?
gram negative
Inhibit bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins (PBPs). Bactericidal.
Beta-Lactam Antibiotics
GI upset or rash (short term), bone marrow suppression, interstitial nephritis (long term), seizures (high doses) are adverse reactions of what?
Beta-Lactam Antibiotics
What are the classes of beta lactam antibiotics?
Penicillin, Beta-Lactamase Combinations, Cephalosporins
Narrow spectrum of action, bactericidal. Susceptible to beta-lactamase (penicillinase). Rapidly excreted. Minimal concentrations attained in CSF.
Penicillin (PCN)
Bactericidal but resists action of beta-lactamase. Broad-spectrum.
Beta-Lactamase Combinations.
True or false: Beta-Lactamase Combinations have better coverage of Pseudomonas than penicillin.
False
Synthetic. Gain more gram-negative coverage and lose gram positive coverage as you increase the generation.
Cephalosporins
True or false: Cephalosporins cover enterococcus.
False. (add ampicillin if suspected).
Which generation of cephalosporins covers HNPEK and CAPES?
4th generation
3rd generation cephalosporin
Ceftriaxone
Which agent has a precaution with calcium containing IV fluids?
Ceftriaxone
True or false: Ceftriaxone is distributed in the CSF.
True
Which agent should be avoided in patients with gallbladder, biliary tract, liver, or pancreatic disease?
Ceftriaxone
5th generation cephalosporin that covers MRSA.
Ceftaroline.
Reaction in <1 hour. IgE mediated hypersensitivity. Anaphylaxis, skin test can be performed to evaluate probability of reaction.
Type 1 Allergic Reaction
What are the two common culprits of Type 1 allergic rxns?
Penicillin and Sulfonamide antibiotics
True or false: A pt can be desensitized by administering small amounts of drug to stabilize IgE.
True
True or false: A patient needs to be desensitized once daily for the drug they are receiving to prevent a reaction.
False: needs to be done EACH TIME they receive the drug.
Reaction in >72 hours. Not IgE mediated, no role for skin testing. Maculopapular or morbilliform rash.
Late Hypersensitivity reactions (types II, III, and IV)
IgG mediated hypersensitivity. Mismatched blood transfusion is an example.
Type II
Immune complex-mediated hypersensitivity. SLE is an example
Type III
Cell-mediated hypersensitivity. Contact dermatitis, MS, Type 1 DM are examples.
Type IV
What percentage of patients with a penicillin allergy have a cross-sensitivity to cephalosporins?
3-7%
What percentage of patients with a cephalosporin allergy have a cross-sensitivity to penicillin?
25%
RIsk (decreases/increases) with increasing generation.
Decreases
Which agent contains a beta-lactam side chain and is used for last line therapy? All are IV products, and high doses lead to seizures.
Carbapenems
What are conditions for using carbapenems?
Long term antibiotic use with continued fever or history of ESBL-producing organisms or suspicion.
Which agent is used to treat gram-negative infections with patients with Type 1 hypersensitivity to beta-lactams?
Monobactam
Which agent from CAPES and HNPEK do monobactams not cover?
Acinetobacter
