Antimicrobials

Question 1

What are treatments based on?

Answer 1

Number of microbes, environmental conditions, time of exposure, microbial characteristics

Question 2

What are the modes of action?

Answer 2

Alteration of membrane permeability, damage to proteins, damage to nucleic acids

Question 3

Why are antimicrobials used in animals?

Answer 3

Therapeutic use, prophylaxis, metaphylaxis, growth promotion

Question 4

What are some chemical ways of controlling microbes?

Answer 4

Phenol (control surgical infections), halogens (iodine that interferes with amino acid complexes), alcohols (does not kill endospores), heavy metals (toxic and corrosive), 4th ammonium compounds (organic matter interferes), oxidizing agents (aseptic packaging)

Question 5

What do broad spectrum antimicrobials protect against?

Answer 5

Gram +, Gram -, Mycoplasma, Rickettsia, Chlamydia

Question 6

What are the advantages and disadvantages of using broad spectrum antimicrobials?

Answer 6

Can be used when the causative agent is not known but can also disrupt normal flora

Question 7

What are the ways of antimicrobial resistance?

Answer 7

Enzymatic inactivation, modify target structure, efflux pump to reduce intracellular concentration, change in metabolic pathway

Question 8

B-lactam

Answer 8

penicillins, cephalosporins, carbapenams, monobactams

Question 9

Aminoglycoside

Answer 9

amikacin, gentamycin, kanamycin, neomycin, streptomycin

Question 10

Aminocyclitols

Answer 10

spectinomycin

Question 11

Macrolides

Answer 11

erythromycin, azithromycin

Question 12

Tetracyclines

Answer 12

oxytetracycline, tetracycline, doxycycline

Question 13

Phenicols

Answer 13

chloramphenicol, florfenicol

Question 14

Lincosamides

Answer 14

lincomycin, clindamycin

Question 15

glycopeptides

Answer 15

vancomycin

Question 16

cyclic peptides

Answer 16

polymyxin

Question 17

quinolones/fluoroquinolones

Answer 17

nalidixic acid, enrofloxacin

Question 18

sulfonamides

Answer 18

sulfa drugs

Question 19

diaminopyrimidines

Answer 19

trimethoprim

Question 20

nitroimidazole

Answer 20

metronidazole

Question 21

nitrofuran

Answer 21

furazolidine

Question 22

Antimicrobials that inhibit cell wall synthesis

Answer 22

penicillins, vancomycin, cephalosporins, carbapenams, bacitracin

PVC pipes Crazy Break cell walls

Question 23

What is important about the semisynthetic drug methicillin?

Answer 23

It was developed to evade penicillinases but led to the development of MRSA

Question 24

What can you do to evade B-lactamases with regards to penicillin?

Answer 24

Combine them with clavulanic acid or sulbactum

Question 25

What are carbapenams used for and what is an important consideration?

Answer 25

Small animals to treat cephalosporin resistant enteric bacteria; there are no vet labeled ones

Question 26

What is an important consideration for the administration of Bacitracin?

Answer 26

only used as a topical because of nephrotoxicity

Question 27

What is important about Vancomycin?

Answer 27

It treats MRSA

Question 28

Antimicrobials that inhibit protein synthesis

Answer 28

Aminoglycosides, aminocyclitols, macrolides, phenicols, lincosamides, pleuromutilins, tetracyclines People Always Love PMAT (because PMAT is phases of the cycle, reminds of protein synthesis)

Question 29

Aminoglycoside properties

Answer 29

binds to ribosomal subunit

Question 30

Aminocyclitol properties

Answer 30

spectinomycin is the only medicine of this for vet, binds to ribosomal subunit

Question 31

Macrolide properties

Answer 31

naturally occurring: erythromycin and tylosin; resistance common by "erm" genes; semisynthetic: tilmycosin

Question 32

Phenicol properties

Answer 32

Chloramphenicol causes aplastic anemia, blocks peptidyl transferase, Florfenicol replaces above in animals

Question 33

Lincosamide properties

Answer 33

bind to ribosome, Clindamycin is semisynthetic for anaerobic infections **Cross resistance between Macrolides, Lincosamides, Streptogramins (MLS)**

Question 34

Pleuromutilin properties

Answer 34

bind to ribosomal subunit, exclusively in animals

Question 35

Tetracycline properties

Answer 35

First broad spectrum discovered

Question 36

Antimicrobials that cause disruption of the cytoplasmic membrane

Answer 36

Polymyxins Myx up the membrane

Question 37

Polymyxin properties

Answer 37

detergent like action and only works as a topical

Question 38

Antimicrobials that inhibit nucleic acid synthesis

Answer 38

Novobiocin, nitroimidazoles, rifamycin, fluoroquinolones, quinolones NNRF quin quin

Question 39

Novobiocin properties

Answer 39

inhibits DNA gyrase, in combo with penicillins and tetracyclines

Question 40

Nitroimidazole properties

Answer 40

unstable intermediates produced-> DNA breakage and occurs in anaerobic conditions, only in small animals

Question 41

Rifamycin properties

Answer 41

related to macrolides, inhibit mRNA synthesis; Rifampin penetrates tissues well

Question 42

Fluoroquinolone properties

Answer 42

divided in three groups: 1) Gram - enteric like nalidixic acid; 2) approved for animals; 3) includes strep and strict anaerobes; increased activity because of membrane penetration; inhibit DNA gyrase through topoisomerases

Question 43

Quinolone properties

Answer 43

Enrofloxacin first used in animals, stopped controlling infection in birds because of concern over resistant bacteria

Question 44

Antimicrobials that are antimetabolites

Answer 44

Sulfonamides-synthetic sulfa drugs, diaminopyrimidines So Done meta-bolism

Question 45

Sulfa drug properties

Answer 45

affect only cells synthesizing folic acid, so only bacteria; resistance is wide so combined with diaminopyrimidine

Question 46

Diaminopyrimidine properties

Answer 46

inhibit dihydrofolate reductase and only used in combo with sulfa drugs; trimethoprim

Question 47

Antimicrobials with random properties

Answer 47

Carbadox (under anaerobic), isoniazid (mycobacterium), ionophore (no therapeutic activity) I-C-O random (I so random)

Question 48

What are some combinations of antibiotics?

Answer 48

penicillin and streptomycin; erythromycin-rifampin

Question 49

What are the reasons you would use combos?

Answer 49

1) treatment of polymicrobial infections, 2) Bactericidal when host defenses are impaired in serious infection; 3) enzymatic destruction of drug overcome with combo; 4) decrease drug toxicity and provide broad spectrum activity