Chapter 10 Antimicrobials

Question 1

MIC stands for:

Answer 1

minimum inhibitory concentration. the minimum amount of a drug needed to inhibit the growth of bacteria

Question 2

MTD stands for:

Answer 2

Maximum Tolerated Dose. Highest concentration tolerated by a patient before adverse reactions or toxicity occurs.

Question 3

Penicillin. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 3

Bactericidal
Used for killing gram-negative bacteria and to treat mastitis in cattle (withdrawal time for food animals)
Can cause anaphylaxis, rash, hives. If given orally, will cause superinfection in guinea pigs, ferrets, hamsters, and rabbits.

Question 4

Cephalosporins. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 4

Bactericidal
Used for urinary tract infections, effective against gram-positive bacteria and pseudomonas.
Hypersensitivity reactions (rash, fever, eosinophilia, hives, anaphylaxis) and superinfection.

Question 5

Aminoglycosides. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 5

Bactericidal
Used against gram-negative, aerobic infections.
Can accumulate in inner ear and kidneys, even at normal doses. Watch for ototoxicity and renal toxicity. Cats more sensitive to this. Must space out doses.

Question 6

Fluoroquinolones. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 6

Bactericidal.
Works well for UTIs, bacterial skin diseases, deep pyodermas, prostate issues,
Disrupts juvenile cartilage. Retinal damage in cats. Caution in animals with seizures.

Question 7

Sulfonamides. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 7

Bacteriostatic by itself, compounded with trimethoprim or ormetoprim is bactericidal.
Effective against gram positive and negative bacteria, and protozoa. (Lots of resistance issues though)
Decreased tear production in dogs (KCS), hypersensitivity reactions on skin, kidney/liver failure, thrombocytopenia, leukopenia, crystal precipitation in kidneys.

Question 8

Tetracyclines. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 8

Bacteriostatic.
Used for tickborne diseases and Wolbachia (heartworm).
Can turn developing teeth yellow, binds with calcium so not effective if given with diary, esophageal strictures in cats, cardiac arrhythmias in horses when given IV. Can also interfere with penicilins/cephalosporins.

Question 9

Lincosamides. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 9

Both bacteriostatic and bactericidal.
Clindamycin used for anaerobic infections (bone infections, dental disease)
Not for use in gut fermenters

Question 10

Macrolides. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 10

Bacteriostatic.
Used for gram positive, respiratory disease. Tylosin sometimes used extra-label for chronic diarrheal syndrome.
GI signs (cramping diarrhea). Tilmicosin If injected IV can cause fatal arrhythmias in some animals and humans

Question 11

Metronidazole. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 11

Bactericidal.
Effective against protozoa that cause intestinal disease.
Reversible transient neurological side effects

Question 12

Chloramphenicol/Florfenicol. Bacteriostatic or bactericidal?
What is it commonly used for?
What are some weird side effects?

Answer 12

Bacteriostatic at lower doses, bactericidal at higher doses.
Florfenicol safe to use for bovine respiratory disease.
Chloramphenicol no use in food animals.

Question 13

Rifampin. Bacteriostatic or bactericidal?
What are some weird side effects?

Answer 13

Bactericidal and bacteriostatic used in conjunction with other drugs.
Can cause reddish-orange saliva, tears, urine, saliva.

Question 14

Amphotericin B. Fungistatic or fungicidal
What is it commonly used for?
What are some weird side effects?

Answer 14

Depending how much, fungistatic or fungicidal.
Used for deep mycoses.
Nephrotoxicosis, fever, anorexia, nausea.

Question 15

Azoles. Fungistatic or fungicidal
What is it commonly used for?
What are some weird side effects?

Answer 15

Takes 5 to 10 days before they become fungicidal.
Treat deep mycoses, Malassezia skin infections.
GI most common side effects, testosterone decrease.
Ketoconazole: teratogenic effects, hepatotoxicity

Question 16

Griseofulvin. Fungistatic or fungicidal
What is it commonly used for?
What are some weird side effects?

Answer 16

Fungistatic
Commonly used for ringworm cases.
Teratogenic , especially in cats. Rarely can cause anemia, leukopenia.

Question 17

What is Terbinafine used for? What are some of its side effects?

Answer 17

Used as alternative treatment for Aspergillosis.
GI effects, low risk of liver toxicity.