Antimicrobial Flashcards
Antimicrobials
Drugs that kill or inhibit the growth of microorganisms
Antibiotics
specifically describe a natural substance produced by one microorganism that suppresses the growth of another microorganism
What are antimicrobials classified according to?
- the type of microorganism it fights
- Whether it kills the microorganism or only prevents it from replicating & proliferating
-cidal
Drugs that kill the named microorganism
Bactericidal, fungicidal, virucidal
-static
Drugs that inhibit replication
Do not directly kill the microorganism
Bacteriostatic, fungistatic
What must time-dependent bacteriostatic and bactericidal drugs maintain?
Concentrations constantly above the minimum inhibitory concentration (MIC)
What are examples of time dependent bacteriostatic drugs?
Chloramphenicol Lincosamide/clindamycin Macrolides Sulfonamides Tetracyclines
What are examples of time-dependent bactericidal drugs?
Cephalosporins
Penicillin family
What are examples of concentration-dependent bactericidal drugs?
Aminoglycosides
Fluoroquinolones
What is the goal of antimicrobial therapy?
To kill or disable pathogens without killing the host
Successful administration of anti-microbials requires the following conditions..
- The microorganism must be susceptible to the antimicrobial drug
- The antimicrobial must be able to reach the site of infection in high enough concentrations to kill or inhibit the microorganism
- The animal must be able to tolerate the required high concentrations of the drug
What is the process of identification and drug susceptibility testing?
Culture and Sensitivity
What does culture and sensitivity determine?
The susceptibility of a bacterial strain to certain drugs
How does culture and sensitivity determine the susceptibility of a bacteria to certain drugs?
By determining how much drug it takes to inhibit or kill the bacteria
What happens when the culture and sensitivity is done?
The bacteria are exposed to increasing concentrations of drug to determine the lowest concentration that inhibits the growth of the cultured bacteria
What is the lowest drug concentration needed to inhibit bacterial growth called?
Minimum inhibitory concentration
What is the highest concentration of a drug that can be tolerated by the animal before significant toxicity signs or adverse effects?
Maximum tolerated dose (MTD)
What needs to happen for a drug to be used systemically to treat an infection?
The drug’s MIC needs to be lower than the concentration of the MTD
Resistant
The MIC is higher than the drug’s MTD