Antibiotics in Food Animals Flashcards

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1
Q

Sulfonamides are time/concentration dependent

A

time dependent

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2
Q

sulfonamides are effective against ______

A

gram (+), gram (-) and some protozoa

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3
Q

organisms known to be resistant to sulfonamides

A

Pseudomonas, Bacteroides, and Enterococcus

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4
Q

T/F sulfonamides are bacteriostatic except potentiated sulfas which are bactericidal

A

True

additives increase strenght/effectiveness (i.e TMS)

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5
Q

where are sulfonamides distributed

A

wide distribution

joints via synovial fluid, CNS, prostate, urine etc - esp potentiated

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6
Q

T/F sulfonamides can be given to dairy cattle

A

False!

only sulfadimethoxine

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7
Q

T/F potentiated sulfas are used off label in calves and pigs

A

true

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8
Q

beta-lactams are time/concentration dependent

A

time dependent

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9
Q

beta lactams are bactericidal/static

A

bactericidal

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10
Q

what are some examples of beta lactams

A

penicillins and cephalosporins

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11
Q

what is the action of beta-lactams

A

bind penicillin-binding proteins

PBP-1 (panems) cause immediate cell lysis

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12
Q

T/F beta-lactams can be combines with a bacteristatic to increase efficacy

A

False!

Bacteria has to have 1 replication cycle for the beta-lactams to be cidal, combining with -statics make them useless

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13
Q

T/F penicillins generally need more time than cephalosporins

A

False

cephalosporins generally need more time than penicillins

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14
Q

______ require more exposure than ______

A

gram (-) require more exposure than gram (+)

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15
Q

how to organisms become resistant/avoid beta-lactams

A

production of beta-lactamase or alter PBP to prevent binding

3rd Generation Cephalosporins are usually unaffected by beta-lactamases

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16
Q

what is the spectrum of natural penecillins

A

gram (+), anaerobes, select gram (-): Listeria; and spirochetes

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17
Q

spectrum of aminopenicillins

A

more gram (-), some stains of E. coli and Salmonella

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18
Q

how does the spectrum of Cephalosporins differ from penicillins

A

similar but more gram (-) coverage as generation increases

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19
Q

T/F beta lactams have poor intracellular activity

A

True

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20
Q

what are some indications for tetracyclines

A

Anaplasma

wooden tongue (Actinobacillus)

lumpy jaw (Actinomycosis)

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21
Q

tetracyclines are ______ dependent

A

AUC/MIC dependent

AUC has to be about 120x MIC to be effective

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22
Q

what is the mechanism of tetracyclines

A

bind to 30s ribosomes, prevents protein synthesis

minimal affinity for mammalian ribosomes

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23
Q

routes of administration of tetracyclines

A

IV, IM, SQ, PO

poor ora absorption - except doxy

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24
Q

distribution of tetracycline

A

lipophillic (intracellular)

wide distribution (most tissues)

accumulate intracellularly, even leukocytes - posible anti-inflammatory effects

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25
Q

how are tetracycline eliminated

A

60% via glomerular filtration

40% through feces

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26
Q

there is increasing concern about ________ with tetracyclines

A

RESISTANCE!

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27
Q

examples of aminoglycosides

A

neomycin and gentamicin

28
Q

aminoglycocides are bacteristatic/cidal and are concentration/time dependent

A

bactericidal

concentration dependent

29
Q

aminoglycoside spectrum

A

primarily aerobic

gram (-)

30
Q

T/F aminoglycosides and tetracyclines are both lipid soluble and act on the 30s ribosome

A

False!

aminoglycosides are highly water soluble and poorly lipid soluble

31
Q

what is meant by post antibiotic effect see with aminoglycocides

A

accumulate in lysosomes and mitochondria

PAE - having effect in the desired area but no longer found in plasma at significant concentrations

32
Q

why is there a long withdrawel period with aminoglycosides

A

chemically attracted to phospholipids

33
Q

what toxicities are seen with aminoglycosides

A

nephrotoxic

ototoxic

these tissues have more phosphatidylinositol in their membranes than other body tissues (mainly gentamicin), this is also there is a concern about residue (kidney)

34
Q

T/F gentamicin is recommended for use in cattle

A

FALSE!

not labeled for cattle! Aminoglycosides are a zero tolerance drugs!

35
Q

what is the current withdrawel time for gentamicin in cattle

A

18 months per single injection for meat

5 days for milk following IV, IM or SQ

36
Q

practictioners are stongly urged to refrain from using aminoglycosides in food animals except ______

A

neonatal pigs

37
Q

what is thought to prevent bacterial inactivation of Florfenicol

A

fluorine at the 3’ carbon position

38
Q

T/F florenfenicol is always bacteriostatic by nature

A

False

  • blocks 50s ribsome, time dependent = static*
  • at peak concentrations = cidal; always cidal for Fusabacterium necroforum*
39
Q

spectrum for florfenicol

A

broad gram (-) → espcially BRD pathogens

some gram (+)

40
Q

indications for florfenicol

A

BRD

keratoconjunctivitis

bovine interdigital phlegmon (aka foot rot)

41
Q

distribution of florfenicol

A

lipid soluble, wide tissue distribution

concentrates in tear film (pinkeye)

CNS - H. somni (above MIC for 20hrs)

diseased lung

high urine concentrates

mammary (mastitis)

42
Q

is extra-label use of florfenicol permitted

A

yes

  • prolonged withdrawal for different than labeled production class*
  • (ex. IM dose in lactating dairy cow has 60 day withdrawal)*
43
Q

examples of macrolides

A

Azalides = Azithromycin, Tulathromycin, Gamithromycin, and Tildipirosin

44
Q

spectrum of macrolides

A

fairly broad

gram (+)

select gram (-) → BRD pathogens

45
Q

Azalides have activity against ________

A

mycoplasma

46
Q

MOA of macrolides

A

inhibit protein synthesis by binding at 50s ribosomal subunit

47
Q

why is there a possible antagonistic effect between macrolides and florfenicol

A

binding sites are close to each other

48
Q

T/F tissue concentrations of macrolides are higher than serum concentrations

A

True

concentrate in cells more acidic than plasma, accumulate in lysosomes of leukocytes

49
Q

macrolides have good absorption through ______

A

the gut

50
Q

lincosamides are primarily used in ______

A

swine

avoid in hindgut and foregut fermenters- clostridial overgrowth

51
Q

MOA of lincosamides

A

inhibit protein synthesis by binding 50s ribosome

52
Q

lincosamides have essentially the same spectrum of activity as _____

A

macrolides

53
Q

lincosamides are used to treat

A

Mycoplasma pneumonia

bacterial arthritis caused by Strep, Erysipelothrix, or Mycoplasma

54
Q

what common adverse effect is seen with lincosamides

A

swelling of the anus

55
Q

what is a highly restricted class of antibiotic that ELDU is strictly forbidden with

A

fluoroguinolones

56
Q

enrofloxacin is approved for use in _______

A

cattle

swine

57
Q

fluoroquinolones are bacteriostatic/cidal and time/concentration dependent

A

bactericidal

concentration dependent

58
Q

spectrum of fluoroquinolones

A

most gram (-)

gram (+) variable susceptibilty - have higher MIC than gram (-)

59
Q

MOA of fluoroguinolones

A

Inhibit bacterial DNA replication & transcription by binding the A subunit of DNA gyrase

60
Q

like beta-lactams, fluoroquinolones should not be paired with a bacteriostatic anitbiotic

A

False

kill bacteria whether they are replicating or not

61
Q

distribution of fluoroquinolones

A

wide

lipid soluble

62
Q

what is the concern with use of fluoroquinolones in food animals

A

concern about transfer of resistance from animals to people

63
Q

what are the bacteria of concern with fluoroquinolones

A

campylobacter

salmonella typhimurium type DT-104

64
Q
A
65
Q
A
66
Q
A