Exam 1: Dr. Austin Handout 2 Flashcards
What is empirical treatment?
Try one agent after another until response is favorable or use combinations of agents
Undesirable because with each unnecessary drug goes the risk of toxic or allergic effects
Undesirable alterations in normal flora or resistance can occur
What is rational treatment?
Choice of the agent that is most likely to act against the pathogen and as few other cells as possible
This is based on in vitro tests, clinical experience, and knowledge of the organism
What is the minimum inhibitory concentration (MIC)?
The lowest concentration of antibiotic capable of preventing growth of a microbe in vitro
What is minimum bactericidal concentration determined by?
Cultures containing drug concentration which show no growth can be subcultures to media without antibiotics
How do you determine if an agent bactericidal?
If the MBC is the same as MIC or within 1-2 dilutions of the MIC
How do you determine if an agent is bacteriostatic?
If higher concentrations than the MIC are required to kill the organism
What does sensitive mean?
MIC is less than the blood urine, or tissue concentrations of the drug given to a patient at a specific dose
What does resistant mean?
The MIC of the organism is greater than the in vivo concentrations of the drug attainable at specified doese
What does intermediate or moderately susceptible mean?
The MIC and the in vivo concentrations are approximately equal
What tests antibiotic sensitivity?
Mueller-hinton agar in disk agar diffusion
What is measured in disk agar diffusion?
Zones of growth inhibition to the nearest mm to convert the measurement into a qualitative category of S, R, or I
What are you indirectly measuring when you measure a zone diameter of no growth?
MIC
