Exam 3 Flashcards
(18 cards)
What characteristics should an ideal antibacterial drug possess?
stability solubility diffusibility slow excretion large therapeutic index
How many antibacterial agents are there?
150 and most are semi-synthetic
What is an antibiotic?
a substance produced by a micro-organism used to kill and/or prevent release of toxins of another micro-organism
What does it mean if a drug is -cidal?
It kills the organism/pathogen
What does it mean if a drug is -static?
It halts growth of the organism/pathogen
What kind of effects can a pathogen have on a host?
opportunistic infections
active/passive immunity
What type of effects can a drug have on a pathogen?
cidal/static effects
What type of effects can a pathogen have on a drug?
resistance
secondary products of bacterial destruction
What is a determinant of which drug you choose, how much drug to use, and drug combinations?
resistance
Why would you use prophylaxis?
to bring likely pathogens down below critical level required to cause an infection. 1/4 to 1/2 of antibacterial use is for prophylaxis
When do you want to use empiric therapy of antibiotics?
when etiology is unknown. May use more than one drug to cover suspected pathogens acquired.
When do you want to use pathogen-directed therapy?
when you know the identification of bacterial species. Can give more specific antibiotic. De-escalate drug use
Why does vancomycin not act against gram negative bacteria?
because its structure is too large to enter porins on the cell wall of the gram negative bacteria
Do gram negative or gram positive bacteria have a thicker peptidoglycan cell wall?
gram positive
Do gram negative or gram positive bacteria have porins in their cell wall?
gram negative
What is MIC and is it used to determine sensitivity for cidal or static drugs?
minimum inhibitory concentration.
used for static drugs
low numbers are good.
What is MBC?
minimum bacteriocidal concentration. used to test sensitivity of cidal drugs.
How do you determine what antibiotic to use?
consider the use (prophylaxis, epmiric therapy), etiology of infection, determine antibiotic sensitivity, location of infection, pharmacokinetics, resistant strains, virulent strains, other host factors (systemic disease, allergies, etc), drug combinations, antibiotic combination
