Overview of antimicrobials Part I, J Kinder, DSA Flashcards

1
Q

Goal of prophylactic therapy

A

prevent infection or prevent dangerous disease in those already infected

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2
Q

what is preemptive therapy

A

targeted therapy in high risk patients who are asymptomatic but have become infected

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3
Q

what is empiric therapy

A

provide antimicrobial therapy to a symptomatic patient without identification of infecting organism

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4
Q

what is definitive therapy

A

infecting organism is known

streamlined therapy based on susceptibility and duration

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5
Q

post Tx suppressive therapy

A

cover patient with antimicrobial therapy at lower dose when infection has not been completely eradicated and immunological or anatomical defect still present which lead to original infection

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6
Q

What is the most valuable immediate test for susceptibility of microbial agent

A

gram stain

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7
Q

What is MIC

A

minimum inhibitory [ ]

lowest [ ] of drug required to inhibit growth

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8
Q

disk diffusion method for determining suscebtibility can qualitatively measure what

A

susceptible or Resistant

not MIC

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9
Q

methods to determine MIC

A

dilution tests and optical diffusion

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10
Q

What is narrow specrum

A

antibacterial acts on single or limited group microorganisms

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11
Q

what is extended spectrum

A

active against gram + bacteria but also against significant number of gram - bacteria

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12
Q

what is broad spectrum

A

act on wide variety bacterial species (both gram + and -)

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13
Q

What is bacteriostatic

A

arrests growth and replication of bacteria

protein synthesis inhibitors

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14
Q

what is bactericidal

A

kills bacteria

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15
Q

types of bactericidal killing

A

[ ] dependent (inc [ ] inc killing)

time dependent )activity continues as long as serum [ ] above minimum bacterial [ ])

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16
Q

what common antibiotics are concentration dependent bactericidals

A

aminoglycosides and fluoroquinolone

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17
Q

what are common antibiotics that are time dependent bactericidals

A

B lactams and vanco

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18
Q

What are common antibacterial targets

A
cell wall synthesis
cell membrane synthesis
synthesis 30S and 50S ribosomal subunits
nucleic acid metabolism
function of topoisomerases
folate synthesis
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19
Q

What are 2 factors assoc with antimicrobial R

A

evolution

clinical/environmental practices

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20
Q

What are the R mechanisms

A
  • reduced entry of antibiotic
  • enhanced export antibiotic
  • release microbial enzymes that kill antibiotic
  • alteration of microbial proteins that transform pro-drugs to the effective moieties
  • alteration of target proteins
  • development of alternative pathways to those inhibited by antibiotics
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21
Q

penicillin structure

A

thiazolidine ring connected to B-lactam ring attached to side chain

22
Q

what determines susceptibility of penicillins

A

side chains

23
Q

MOA of penicillins

A

inhibit transpeptidation reaction, last step in peptidoglycan synthesis
Penicillin binding proteins remove terminal D alanine
B lactams are analogs of D-ala D-ala so bind PBP and prevent their crosslinking
leads to cell autolysis

24
Q

How does R happen to penicillins

A

structural differences in PBPs and dec PBP affinity for B lactams
active efflux pumps
drug destruction!!
inactivation by B lactamases

25
Q

what are aminopenicillins used for

A

extended spectrum, usually given with B lactam inhibitor

26
Q

What are the aminopenicillins

A

ampicillin (+/-sulbactam)

amoxicillan (+/-clavulanic acid)

27
Q

Therapeutic use of aminopenicillins

A

URI (S pyogenes, S pneumoniae, H influenzae, sinusitis, otitis media, enterococcal infections)

28
Q

What type of spectrum are anti-pseudomonal penicillins and what are they types

A

extended spectrum
ticarcillin (+/-clavulanic acid)
piperacillin (+/- tazobactam)

29
Q

Therapeutic use of anti-pseudomonal penicillins

A

serious gram - infections, hospital acquired pneumonia, immunocompromised patients, bacteremia, burn infections, UTI

30
Q

What are the adverse effects of anti-pseudomonals

A

allergic rxns, anaphylaxis, interstitial nephritis (rare), nausea, vomiting, mild-severe diarrhea, pseudomembranous colitis

31
Q

cephalosporins have same MOA and R as what class of antibiotics

A

penicillins

32
Q

cephalosporins do not have activity for what microbes

A

MRSA, listeria or enterococci

33
Q

activity of 3rd generation cephalosporins

A

less active against gram +

more active against enterobacteriae

34
Q

What drugs are 3rd generation cephalosporins

A

Ceftriaxone, ceftazidime

35
Q

Tx use of 3rd generation cephalosporins

A

DOC serious gram - infections (Klebsiella, enterobacter, Proteus, Providencia, Serratia, Haemophilus)

36
Q

ceftriaxone is DOC for what

A

all forms gonorrhea and severe lymes disease, meningitis

37
Q

activity of 4th generation cephalosporins

A

extends spectrum beyond 3rd generation

serious hospitalized patients

38
Q

What drugs are 4th generation cephalosporins

A

cefepime

39
Q

Therapeutic use of cefepime

A

empiracal Tx of nosocomial infections

40
Q

adverse effects cefepime

A

1% cross reactivity to penicillins, diarrhea, intolerance to alcohol

41
Q

MOA and R carbapenems is similar to what other drug class

A

penicillins

42
Q

spectrum of carbapenems

A

aerobic and anaerobic microorganisms, gram +, excellent against enterobacteriacae, PSeudomonas, Acinetobacter

43
Q

Therapeutic uses of carbapenems

A

UTI, lower RTI, intra-abdominal, gynecological, SSTI, bone and joint infections
ALL IV or IM

44
Q

what is beneficial about ertapenem

A

longer half life which allows for once daily dosing

45
Q

Adverse effects of carbapenems

A

nausea/vomiting, seizures, HS

46
Q

MOA glycopeptides

A

inhibits cell wall synthesis binding with high affinity to D alanylD alanine terminal
Unable to penetrate outer membrane gram - bacteria

47
Q

Bacterial Resistance of glycopeptides

A

alteration of Dalanyl D alanine to D alanyl D lactate or serine

48
Q

spectrum of glycopeptides

A

broad gram + coverafe inclusing MRSA, MRSE

all gram - and mycobacterium resistant

49
Q

Therapeutic use of glycopeptides

A

osteomyelitis, endocarditis, MRSA, strep, enterococci, CNS infections, bacteremia,
orally for Clostridium difficile!

50
Q

adverse effects glucopeptides

A

macular skin rash, chills, fever,rash
red man synfrome from rapid infusion
release of histamine from toxic effect vanco
ototoxicity and nephrotoxicity