What factors must be considered in choosing an antimicrobial agent?
identity of infecting organism, information about the susceptibility of the infecting organism, factors specific to the patient
What is empiric theory?
the application of knowledge of the organisms most likely to cause infection in a given clinical setting and its most likely susceptibility to an antibiotic
Why is knowing the susceptibility of the organism important in choosing an antibiotic?
organisms exhibit intrinsic or innate resistance to certain antibiotics so you won’t consider these, while some are universally susceptible to certain antibiotics
What factors to the patient are important to consider when choosing an antibiotic?
history of previous reactions, age (gastric acidity changes with age - important for orally ingested), pregnancy, renal/hepatic function, site of infection
pharmacokinetics
encompasses all the ways that the body manipulates a drug, including absorption, distribution, metabolism, and excretion
pharmacodynamics
describes the biochemical and physiologic effects of the drug and its metabolism of action on the bacteria
bacteriostatic
antimicrobial agents that inhibit the growth and/or reproduction of the infecting agent, but fail to actually kill the agent
Why is bacteriostatic typically better than bacteriocidal?
normal defenses typically destroy the microorganism
What are examples of bacteriostatic agents?
macrolids (erythromycin), clindamycin, sulfamethoxazole, trimethoprim, tetracyclines, chloramphenicol
bacteriocidal
antimicrobial agent that is capable of causing irreversible damage or death to the organism
What are examples of bacteriocidals?
b-lactam antibiotics (penicillins and cephalosporins), vancomycin, aminoglycosides, fluoroquinolones
What is a factor that can influence if a antimicrobial is bacteriostatic or bacteriocidal?
antimicrobial concentration at the site of action - can be bacteriostatic at low concentrations and bactericidal at high concentrations
MIB
Minimal bacteriocidal concentration - the lowest concentration which prevents the organism from multiplying
broad spectrum antibiotics
active against wide range - usually both gram positive and gram negative
When are broad spectrum typically used?
empirically prior to identifying the causative bacteria (wide differential and potentially serious illness)
narrow spectrum antibiotic
active against a select group of bacterial types
What are the five mechanisms antibiotics inhibit/kill bacteria?
interfere with cell wall synthesis, protein synthesis, cytoplasmic membrane function, nucleic acid synthesis, metabolic pathway
What are antibiotics that interfere with cytoplasmic membrane function tricky?
all organisms have a cytoplasmic membrane
What antibiotics interfere with cell wall?
beta lactams (penicillin, cephalosporin, carbapenems, monobactams), vancomycin, bacitracin
What antibiotics interfere with cell membrane?
polymyxins
What antibiotics interfere with folate synthesis?
sulfonamides, trimethoprim
What antibiotics interfere with DNA gyrase?
quinolones
What antibiotics interfere with RNA polymerase?
rifampin
What antibiotics interfere with ribosome subunits?
macrolides, clindamycin, linezolid, cholamphenicol, streptogramins, tetracyclines, aminoglycosides
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Immunology Lecture 131
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Immunology Lecture 2.21
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Immunology Lecture 3.12
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Immunology Lecture 4.15
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Immunology Lecture 5.15
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Immunology Lecture 6.21
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Immunology Lecture 7.21
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Immunology Lecture 8.21
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Immunology Lecture 9.18
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Immunology Lecture 10.31
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Immunology Lecture 11.25
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Immunology Lecture 12.26
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Immunology Lecture 13.17
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Immunology Lecture 14:15.24
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Micro poop 1.32
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micro poop 2.50
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micro poop 3.38
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micro poop 4.15
