Chapter 15

antimicrobial drugs

therapeutic compounds that kill microbes or inhibit their growth

who invented penicillin

alexander fleming

broad spectrum drugs

effective against both gram negative and gram positive bacterial cells

narrow spectrum drugs

target a limited range of bacteria

empiric therapy

treatment based on clinical presentation in the absence of definitive or complete clinical data is started to protect the patient

why are broad spectrum antibiotics only used for a short amount of time

minimal damage to the microbiota

What infection are hospitalized patients at risk for due to prolonged use of broad-spectrum antimicrobial drugs?

Clostridium difficile infection

bacteriostatic

preventing bacteria from growing

bactericidal

actively killing bacteria

What is a serious drawback that can occur when using a bactericidal drug for an endotoxin-producing Gram-negative bacterial infection?

could trigger a dangerous surge in LPS (endotoxin) levels in the patient

antibiotics

naturally occurring antimicrobial

synthetic antimicrobials

wholly manufactured by chemical processes; can overcome antibiotic resistance mechanisms that naturally evolve as pathogens encounter our pharmacopeia of drugs

semisynthetic antimicrobials

naturally occuring; can be chemically modified to improve their pharmacological actions and/or stability

drugs that have been modified from their core molecule are denoted by

generations

Which of the following would be oldest generation drug?

first generation drugs

Which would be the newest generation drug?

2nd generation

Which would have the most expanded capabilities over their predecessors?

newer generation drugs

Define the selective toxicity of a drug.

inhibits or kills the targeted microbe without damaging host cells 

What is the therapeutic index of a drug?

ratio of the maximum tolerated or safe dose to the minimum effective or therapeutic dose

A drug with a high therapeutic index is safer that a drug with a narrow therapeutic index.

true 

Because the kidneys and liver are key organs that metabolize and eliminate drugs

they may be particularly susceptible to damage by certain drugs

What is the general name for a drug that is toxic to the kidneys?

nephrotoxic antimicrobial drugs

What is the general name for a drug that is toxic to the liver?

hepatotoxic antimicrobial drugs

When talking about drugs, what is half-life?

time is takes for half of a dose to be eliminated or deactivated by the body - often by the kidneys or liver

how does bacteriostatic work

proteins that inhibit protein synthesis or block metabolic pathways

how does bactericidal work

drugs thats target the bacterial cell wall, membrane, or nucleic acids (DNA or RNA act as bactericidal drugs

What superfamily of drugs work by blocking cell wall synthesis?

beta-lactam antimicrobials 

What molecule do most bacterial cell walls consist of?

Peptidoglycan

What is the function of beta-lactamases?

enzymes that inactivate beta lactam drugs