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ACVECC > Antibiotics > Flashcards

Antibiotics Flashcards

1
Q

Gram + Antibiotics

A

Beta lactams
- Penicillines
- Cephas
- Carbapenems

Macrolides
- Erythromycin
- Azithromycin

Glycopeptides
- Vancomycin

**Gram+ but may vary

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2
Q

Gram Negative antibiotics

A

Aminoglycosides
Fluoroquinolones
2-4th cephalosporins

Gram - and Fx2-4

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3
Q

Broad spectrum antibiotics

A

Tetracyclines
TMS
Chloramphenicol
vanc
linazolid
2nd-4th gen cephas
carbapenems

**Tries to look very casual clocking 2-4

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4
Q

Anaerobic coverage

A

Azithromycin
Chloramphenicols
Metronidazole
Lincosamides –> clindamycin
Beta Lactams
- Pens: clostridium, peptostreptococci, actinomyces, fusobacterium
-Aminopen-clav against bacterioides
-cephas

** Anaerobes are clearly more like Bitches

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5
Q

Bacteriostatic antibiotics

A

Interferes with protein production, DNA replocation or cellular metabolism

  • Stops reproduction but depends on immune system to kill bacteria

Tetracyclines
Chloramphenicol
Lincosamides (clindamycin)
Macrolides

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6
Q

3 types of resistance

A
  1. intrinsic: inherent feature of microbes to be resistant to drug (ex: pseudomonas is intrinsically resistant to beta lactams)
  2. Circumstantial: susceptible in vitro, but resistant in vivo (ex: inactivated by platelets or cant reach site like CSF)
  3. Acquired: change in phenotypic characteristic
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7
Q

Inhibitory quotient

A

Cmax/MIC

High inhibitory quotient must be achieved to reliably kill offending organism with concentration dependent antibiotics

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8
Q

MRS

A

MC Staph pseudointermedium then aureus

-MOA: acquired mecA gene –> alters PBP
- Also resistent to clinda, fluoroquinolones, macrolides & TMS

Escalation protocols:
- Aminoglycosides - will not act in puss or cellular debris
- Vancomycin drug of choice ((linesolid indicated if resistant or oral therapy needed))
-Tetracyclines, chloramphenicol, rifampin

*Staph be calling man fucking tyrant

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9
Q

MDR Enterococcus

A

E. Faecalis & E. Faecium

INtrinsic resistance to cephas, clinda, aminoglycosides & fluoroquinolones

Acquired MOA: aminoglycoside-modifying enzymes (AME) or alterations on PBP5

Fluoroquinolone + Cepha use assd with development of vanc resistent MDRE!!!

Treatment options:
-Gentamicin + amp –> synergistic ( no other Aminos synergistic)
- Vancomycin (linesolid indicated if resistant or oral therapy needed)

**Often nosocomial

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10
Q

Pseudomonas aeroginosa

A

Intrinsic resistance: majority beta lactams (exc ticarcillin, pipercarcillin ceftazadime & carbapenems), quinolones & aminoglycosides

Acquired 3 MOAs:
- Decreased intracellular drug due to efflux pumps or altered membrane structure
-Enzymes modify/destroy antibiotics
-Modify target of antibiotics (DNA gyrase mutation)

Treatment often requires amikacin or carbapenem

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11
Q

RNA synthase inhibitors

A
  • Inhibits RNA polymerase
  • lipohilic
  • Hepatic clearance
  • ABX: Rifampin

Side effects: discolored urine, GI, hepatotoxicity, hypersensitivity

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12
Q

Protein Synthesis Inhibitors

A
  • Inhibit 30s & 50s ribosome units –> prevent mRNA translation

30s inhib: aminoglycosides, tetracyclines

50s inhib: macrolides, chloramphenicol, clindamycin

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13
Q

DNA synthesis inhibitors

A

-INhibits DNA gyrase & topisomerase IV
- lipophilic
-Renal/hepatic clearance
- ABX: fluoroquinolones, metronidazole

Side Effects: GI, nephrotoxicity, cartilage damage, hepatotox, hypersensitivity

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14
Q

Cephalosporins

A
  • Inhibit cell wwall synthesis
  • Bacteriocidal
  • Hydrophilic–> renal clearance
  • Time dependent
  • Aerobic bacteria
  • 1st gen> Gram + coverage
  • 3 & 4 gen > gram+ & Gram -

*3rd gen ideal for CNS

Ceftazadime –> labeled for pseudomonas

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15
Q

Carbapenems

A
  • Cell wall synthesis inhibition
  • Hydrophilic – renal clearance
  • Time dept
  • Bacteriocidal
  • 4 quad coverage

-Withstand beta lactamases (even ESBL)

Imipenem: inc Gram + for E. Faecalis –> neuro signs poss
Meropenem: inc gram - including pseudomonas
Etrapenem: no activity against enterococci

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16
Q

Macrolides

A

Inhibit ribosomal 50s subunit
-Lipophilic –> hepatic clearance
- Concentration dependent- azithromycin
- Time dep + conc enhanced– erythromycin
-Aerobic Gram + & - & atypical bacteria
-bacteriostatic
- Concentrated in macs–> get to infection

Side effects: GI upset, hypersensitivity–> products of streptomyxces species

17
Q

Vancomycin

A
  • Cell wall synthesis inhibition
  • Hydrophilic - renal clearance
  • Time Dept
  • Gram + coverage, MRSA, & enterococcus sp
  • Bacteriocidal
18
Q

Augmented renal clearance

A
  • In critically ill: increased renal clearance due to increase CO with decrease SVR
  • Human Study: antibiotic clearance 3x with normal Crea
    **MC in trauma, sepsis, blood malignancies & pancreatitis
19
Q

TMS combos

A
  • Inhibit enzymes in folic acid synthesis pathway
  • Sulfas–> static
  • trimethoprim - cidal
  • Sulfa+ trimetho = cidal
  • Gram +/- & protozoa
  • Renal excretion, metabolism by liver

Side effects: KCS (reversible), hepatitis, hemolytic anemia, leukopenia, GI
Hypersensitivities in Dobies

20
Q

Chloramphenicol

A
  • Inhibits ribosomal 50s subunit
  • Bacteriostatic
  • Time dependent
  • 4 quadrant coverage, rickettsial, mycoplasma, chlamydia
  • EXTENSIVE liver metabolism
  • Gram neg resistance via acetylation & inactivated by bascterial enzymes

Side effects: GI upset, hypersensitivity

21
Q

Nitromidazoles

A
  • ie metronidazole
  • Disrupt DNA by forming reactive intermediates
  • Bacteriocidal
  • Concentration dept
  • ONly active in anaerobic conditions
    Excellent distribution –> including CNS & abscess
22
Q

Lincosamides

A
  • Inhibit protein synthesis via binding 50s ribosomeal subunit
  • bacteriostatic
  • Gram + aerobes, most anaerobes, intracellular bacteria
  • Reach high concentrations in abscesses

Ex: clindamycin, lincomycin (less active against anaerobes)

23
Q

Antibiotics for resistant infections

A
  • Carbapenems
  • Glycopeptides –> vancomycin
  • Oxazolidinones –> linazolid
24
Q

Oxazolidinones

A

MOA: inhibit protein synthesis by binding to bacterial 23s rRNA of 50s subunit

-Static against most bacteria, maybe cidal in vivo

  • Resistant Gram + bacteria (streptococci, enterococci)

Ex: linezolid $$$

25
Q

Clindamycin

A
  • Inhibit ribosomal 50s subunit
  • lipophilic
  • hepatic clearance
  • Time Dept + concentration enhanced (PAE)
  • Gram + - aerobic & anaerobic
  • Gram - anaerobic

Side effects: GI, hypersensitivity

26
Q

Bacteriocidal

A

Kill bacteria via inhibition of wall synthesis, bacterial enzyme inhibition or protein translation

27
Q

Rifampin

A
  • Inhibits RNA polymerase
  • lipophilic
  • kepatic clearance

Side effects: discoloer urine, GI, hepatotoxicity, hypersensitivity

28
Q

Antiobiotics with MOA cell wall synthesis inhibition

A
  • Block cross linking of peptidoglycans –> cell lysis
  • Hydrophilic
  • renal clearance
  • Abx classes: penicillins, cephas, vancomycin, monobactams, carbapenems, bacitracin

Side effects: GI, hypersensitivity, neurotoxicity

29
Q

Monobactems

A
  • Cell wall synthesis inhibition
  • Hydrophilic
  • Renal clearance
  • Bacteriocidal
  • Time dependent
  • Not used in vet med
30
Q

Time Dept vs Concentration Dept

A

TIme: amount of time antibiotic agent is above MIC of infecting organism
* ideally above this for 100% of time

Concentration: Max antibiotic effect when peak drug concentration exceeds MIC several times (>8-10x MIC)
Cmax above MIC –> area under curve

31
Q

Bacitracin

A

Cell wall synthesis inhibition
Hydrophilic
Renal clearance

32
Q

Tetracyclines

A
  • Inhibit ribosomal 30s subunit
  • Lipophilic
  • renal & hepatic clearance
  • time dependent + PAE (conc enhanced)
  • Bacteriostatic
  • Aerobic gram- & +
    Atypicals: rickettsia, mycobacteria, treponema, chlamydia, mycoplasma

**Delayed bone growth, esophageal stricture

33
Q

Penicillins

A
  • Cell wall synthesis inhibition
  • Renal Clearance
  • Hydrophilic
  • Time dependent
  • bacteriocidal
  • Gram + bacteria
  • Aerobic>anaerobic

– PenG –> strep!! (necrotizing fasciitis (not against staph)
–Aminopenicillins – susecpt beta lactamases –> increased effect against gram -
– Ticarcillin/piperacillin –> active against pseudomonas & proteus (none against ecoli)

34
Q

Post antibiotic effect

A
  • occurs because bacteria need to make new proteins
  • Drugs with prolonged PAE:
    Clindamycin
    Erythromycin
    Linezolid
    Tetracycline
35
Q

Fluoroquinolones

A
  • Inhibit DNA gyrase (gram -) & topoisomerase IV (gram +)
  • lipophilic
  • Hepatic/renal clearance
  • Concentration dependent
  • bacteriocidal, marked PAE
  • Intracellular pathogens: mycoplasma, chlamydia, brucella
  • Decreased absorbtion with polyvalen cations (calcium, magnesium, aluminum, iron, zinc)

Side Effects: GI, neurotoxicity, cartilage damage, hepatoxic hypersensitivity, inhibit P450

4 Quad coverage:
- Ciproflox –> inc gram -
- levoflox –> inc gram +

36
Q

Aminoglycosides

A
  • 30s subunit inhibition
  • Gram - & select gram + coverage (staph sp)
  • Synergistic with beta lactams
  • Long PAE
  • Adaptive resistance: after first exposure, decreased uptake –> give once daily to avoid this!
  • Distribute well in ECF
  • NMJ blockade: inhibit presynthesis calcium –> reverse with calcium or neostigmine
    ** Quinolones can also do this!

Side effects: ototoxicity, nephrotox

Ex: amikacin, gentamicin, neomycin

37
Q

Metronidazole

A
  • Inhibits DNA gyrase & topoisomerase IV
  • lipophilic
  • hepatic/renal clearance
  • concentration dependent
  • Anaerobic - gram - & gram +

Side effects: GI, neurotoxicity, hepatotoxicity, hypersensitivity

38
Q

Definition MDROs

A

Organism not susceptible to at least one agent in 3 or more classes of antimicrobials to which they are susceptible

39
Q

ESBL

A

Extended spectrum B lactamases
- hydrolyze third generation cepha’s beta lactam ring, but carbapenems still stable against these abx (not true for XDR)

Primary infections: E. Coli, Klebsiella pneumoniae, & enterobacter specieas

ACVECC (10 decks)

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