Rational Antimicrobial Therapy p1391-1406 Flashcards
Define MIC and MBC, in terms related to antimicrobials. Which of these is most used by laboratories?
MIC - minimum inhibitory concentration, meaning the lowest concentration of drug that will inhibit visible growth
MBC - minimum bactericidal concentration, the lowest concentration of drug that results in no growth
MBC is more expensive, so is not determined in most laboratories
Which of the following are characteristics of A) concentration-dependent drugs vs. B) time-dependent drugs?
- Antimicrobial activity best predicted by relationship between peak drug concentration and MIC of the organism
- Dosed more frequently or continuous rate of infusion
- Drug should remain above MIC for more than 50% of the time
- Prolonged post-antibiotic effect
- Antimicrobial activity best predicted by duration that the drug concentration is above the MIC
- Aminoglycosides
- Beta-lactams
- Fluroquinolones
- Glycopeptides
- Macrolides
- Sulfonamides
- Tetracyclines
- Trimethoprim
A - Antimicrobial activity best predicted by relationship between peak drug concentration and MIC of the organism
B - Dosed more frequently or continuous rate of infusion
B - Drug should remain above MIC for more than 50% of the time
A - Prolonged post-antibiotic effect
B - Antimicrobial activity best predicted by duration that the drug concentration is above the MIC
A - Aminoglycosides
B - Beta-lactams
A - Fluroquinolones
B - Glycopeptides
B - Macrolides
B - Sulfonamides
B - Tetracyclines
B - Trimethoprim
List the major food-producing species in the US.
Cattle, swine, chickens and turkeys
List the minor-food producing species in the US.
Goats, sheep, cervids
For each class of antimicrobial, determine if activity is bactericidal (C) or bacteriostatic (S).
- Aminoglycosides
- Beta-lactams
- Fluroquinolones
- Glycopeptides
- Macrolides
- Sulfonamides
- Tetracyclines
- Trimethoprim
C - Aminoglycosides C - Beta-lactams C - Fluroquinolones C - Glycopeptides S - Macrolides S - Sulfonamides S - Tetracyclines S - Trimethoprim (unless combined with sulfonamide)
List drugs that are PROHIBITED for use in food animals. (13 in total)
Diethylstilbestrol Chloramphenicol Phenylbutazone Nitrofurans Nitromidazoles Estradiol cypionate Glycopeptides Clenbuterol Antiviral drugs in poultry Dipyrone Genetian violet Hormone implants in veal calves Dimethyl sulfoxide and colloidal silver
List drugs that are PROHIBITED for ELDU in food animals species.
Cephalosporin-class abx
Sulfonamides in dairy cattle
Fluoroquinolones
With the following properties, determine which antibiotic is described.
Labeled to treat cattle and sheep for shipping fever caused by Pasteurella multocida, pigs for erysipelas, and horses for Strep equi.
An effective bacteriocide that works by inhibiting cell wall synthesis, this antimicrobial is largely effective agains Gram (+) species.
Not to be used in horses intended for food. Milk withdrawal is 48 hours. Meat withdrawal is 4 days for cattle, 8 days for sheep, 6 days for swine and 7 days for non-ruminating calves.
A) Penicillin G
B) Oxytet 100
C) Excede
D) Draxxin
A) Penicillin G is a beta-lactam, that is time dependent antimicrobial.
With the following properties, determine which antibiotic is described.
Labeled to treat shipping fever in cattle due to Pasteurella, enteritis due to E. coli, foot rot and calf diptheria due to Fusobacterium, woody tongue due to Actinobacillus lignieresii. Used to treat Anaplasmosis, Potomac Horse Fever and Lawsonia intracellularis.
An effective bacteriostatic against both Gram (+) and Gram (-) bacteria, by inhibiting 30s protein synthesis.
Meat withdrawal is 22 days. NOT for use in lactating dairy animals, no withdrawal period established for pre-ruminating calves, NOT for use in veal calves.
A) Penicllin G
B) Oxytet 100
C) Draxxin
D) Nuflor
B) Oxytet 100 is a tetracycline, time-dependent antimicrobial that needs to be given slowly if given IV.
Oxytet 200 has the same withdrawal period while Oxytet 300 has a slightly longer meat withdrawal at 28 days.
Oxytet 200 and 300 are also labeled for pink eye due to moraxella bovis, leptospirosis by Leptospira pomona,
With the following properties, determine which antibiotic is described.
Labeled for BRD associated with Mannheimia, Pasteurella, and Histophilus in beef, non-lactating dairy and lactating dairy cattle; foot rot caused by Fusobacterium and Porphyromonas levii; acute metritis of lactating cattle (0-10 day pp); lower respiratory tract infections in horses caused by Strep. zoo.
A bactericidal effective against Gram (+) bacteria, sometimes Gram (-), works through inhibition of cell wall synthesis.
Withdrawal times for a single dose or a 2-dose regimen is a 13 days pre-slaughter, and no milk withdrawal period. Withdrawal is not established for use in pre-ruminants and NOT to be used in veal calves.
A) Glycopeptides
B) Naxcel
C) Excede
D) Oxytet
C) Excede is a 3rd generation cephalasporin that is time-dependent.
With the following properties, determine which antimicrobial is described.
Labeled for BRD associated with Mannehimia, Pasteurella and Histophilus; foot rot assoc with Fusobacterium necrophorum and Bacteroides melaninogenicus; swine RD assoc with Actinobacillus, Pasteurella, Salmonella and Streptococcus; sheep RD assoc with Mannheima haemolytica and Pasteurella; goat RD assoc with Mannheimia and Pasteurella; equine RD assoc with Strep. zoo
Effective against Gram (+) and sometimes Gram (-), bacteriocidal by inhibiting cell wall synthesis
NO milk withdrawal and 4 day meat withdrawal.
A) Naxcel
B) Penicillin G
C) Oxytet
D) Albon
A) Naxcel is a 3rd cephalosporin, time dependent antimicrobial.
Similar to Naxcel is Excenel, which is labeled for BRD and foot root and metritis in cattle and respiratory disease in swine as well. The withdrawal is also 4 days for meat and has no milk withdrawal.
With the following properties, determine which antimicrobial is described.
Labeled for BRD in beef and non-lactating dairy cattle assoc. with Mannheimia, Pasteurella, Histophilus and Mycoplasma; IBK assoc. with Moraxella; foot rot assoc. with Fusobacterium and Porphyromonas levii; BRD in suckling calves, dairy calves and veal calves; SRD assoc. with Actinobacillus, Pasteurella, Bordetella, Haemophlus, and Mycoplasma hyopneumoniae and Actinobacillus, Pasteurella and Mycoplasma
Effective against both Gram (+) and Gram (-), this bacteriostatic antimicrobial works by inhibiting 50s protein synthesis
Meat withdrawal is 18 days and is not approved in dairy cattle above 20 mth of age or older, including dry cows. Withdrawal for pork is 5 days.
A) Nuflor
B) Draxxin
C) Excede
D) Penicllin G
B) Draxxin is a macrolide, time-dependent.
With the following properties, determine which antimicrobial is described.
Labeled for BRD assoc. with Mannheimia, Pasteurella and Histophilus; foot rot assoc. with Fusobacterium and Bacteroides
An effective bacteriostatic that works by inhibiting 50s protein synthesis, against both Gram (+) and Gram (-)
A) Excenel
B) Penicillin G
C) Oxytet
D) Nuflor
D) Nuflor is a phenicol antimicrobial, related to chloramphenicol, WHICH IS PROHIBITED IN FOOD ANIMAL USE.
Which of the following antimicrobials work by inhibiting 30s protein synthesis?
Aminoglycosides Beta-lactams Fluroquinolones Glycopeptides Macrolides Sulfonamides Tetracyclines Trimethoprim Phenicols
Aminoglycosides & Tetracyclines
Which of the following inhibit 50s protein synthesis?
Aminoglycosides Beta-lactams Fluroquinolones Glycopeptides Macrolides Sulfonamides Tetracyclines Trimethoprim Phenicols
Macrolides & Phenicols
