Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

pr3151 > principles of antimicrobial use > Flashcards

principles of antimicrobial use Flashcards

1
Q

what are the impacts of inappropriate antimicrobial use

A

poor patient outcomes and excess costs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are some poor patient outcomes as a result of inappropriate antimicrobial use

A

ADR, organ toxicity, superinfection, abx resistance due to selection pressure, increase mortality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are some examples of excess costs as a result of inappropriate antimicrobial use

A

drug acquisition cost, management of complications, prolonged hospital stay, costs associated with abx resistance1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the impacts of abx resistance

A

infections are more difficult to treat, require use of more expensive and more toxic abx, increase length of hospital stay due to more complications, increase healthcare costs, increase mortality and morbidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the cause of abx resistance

A

broad spectrum abx kills off many normal microbiota which then allows other bacteria to invade and cause another infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is an infection

A

an infection is when an organism invades the host tissues and elicit inflammatory host responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the symptoms of an infection

A

erythema, fever, swelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the spectrum of infection

A

mild - localised and self limiting, moderate - systemic and non life threatening, severe - life threatening, septic shock - profound hemodynamic (dysregulated HR and BP) and metabolic (acidosis) abnormalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is sepsis

A

sepsis is a life threatening organ dysfunction caused by a dysregulated host response to an infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the approach to antimicrobial use

A

confirm presence of infection, identify pathogen, selection of antimicrobial and regimen, monitor response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the steps to confirming the presence of an infection

A

risk factors, subjective and objective evidence, what are the possible sites of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the risk factors of an infection

A

disruption of natural protective barriers (innate immunity), age, immunocompromised, alterations in normal flora leading to an overgrowth of microorganisms in the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are some conditions that promote alterations in host’s normal flora

A

use of abx and uncontrolled blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what groups of people may be immunocompromised

A

malnutrition, underlying disease, drugs (chemo, steroids, immunosuppressants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are subjective evidences

A

localised and systemic symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are some localised symptoms that may point towards an infection

A

N,V,D, abdominal distension, cough and purulent sputum, dysuria, frequency and urgency, pain and inflamm at site of infection, erythema, swelling and warmth, purulent discharge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are some systemic symptoms that may point towards an infection

A

feverish, chill rigors, malaise, palpitations, shortness of breath, mental status changes, weakness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are objective evidence

A

vital signs, lab tests and radiological imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are some vital signs to look at to confirm presence of infection

A

fever, hypotension, tachypnea, tachycardia, mental status

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are some lab tests markers

A

elevated or depressed WBC, increased neutrophils, increased CRP, increased erythrocyte sedimentation rate, increased procalcitonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are some examples of radiological tests

A

x ray, CT scan, MRI, ultrasound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the values for fever, hypotension, tachypnea, tachycardia

A

fever >38degC, hypotension SBP<100mmHg, tachypnea RR>22bpm, tachycardia HR>90bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how to determine the possible site of infection

A

based on clinical presentation, risk factors of possible sites, subjective and objective evidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the role of procalcitonin

A

supplements clinical assessment, only used if can help to determine presence of bacterial infection, reflects severity of bacterial infection, guides initiation and discontinuation of abx, monitor progression of infection or response to treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are the guidelines for starting or stopping use of abx based on procalcitonin levels

A

starting: conc <0.25mcg/L strong discouraged, conc = 0.25 <0.5 discouraged, conc = 0.5 <1 encouraged, conc >1 strongly encouraged

stopping: conc <0.25 strong encouraged, conc decr by > equal 80% or conc 0.25 <0.5 encouraged, conc decr by < 80% or conc > equal 0.5 discouraged, increase in conc compared to peak and conc > equal 0.5 strongly encouraged to change abx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are pathogens

A

pathogens are organisms that are capable of damaging and invading host tissues and eliciting a host response and signs and symptoms of an infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

where are pathogens derived from

A

may be acquired from environment or from normal flora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are colonisers

A

colonisers indicate presence of normal flora or pathogenic organisms without eliciting a host response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is the likely coloniser in urine culture

A

yeast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the likely coloniser on skin

A

coagulase negative staphylococcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are contaminants

A

presence of microorganism typically acquired during collection or processing of host specimen without evidence of host response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are likely contaminants in blood culture

A

staphylococcus epidermis, bacillus spp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why should you obtain a culture before administering antimicrobials

A

follow up cultures are less reliable than pretreatment cultures and may result in false negative and may not reflect the initial causative organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what are the types of microbiological tests that can identify pathogen

A

initial gram stain, antimicrobial susceptibility test (AST)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what are the considerations when identifying pathogen

A

is it usually on site, single growth or mixed growth, signs of invasion of tissues, isolated from multiple cultures or specimens, epidemiology and likelihood of pathogen in causing disease/ infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what does single growth pathogen suggest

A

more likely to invade tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what does mixed growth pathogen suggest

A

other microbiota can help prevent disease

38
Q

what are the types of antimicrobial regimens

A

empiric, definitive, prophylaxis

39
Q

when is empirical therapy started

A

when microbiological results not available

based on clinical presentation, likely microorganism at that site of infection, likely susceptibility from antibiogram or from spectrum of activity

40
Q

what is definitive therapy and when is it started

A

definitive therapy is culture directed therapy

based on patient specific microbiological results (culture and susceptibility)

41
Q

what is antibiotic prophylaxis

A

abx given to prevent an infection

42
Q

what are the principles of abx use

A

timely initiation of appropriate agents (most effective, least toxic and narrowest spectrum possible), administration of dosage individualised to patient and appropriate to microorganism and site of infection, timely and appropriate alteration in response to clinical responses and microbiological data (use for shortest time possible)

43
Q

what are organism factors to consider

A

indentity of organism (fungal, bacteria, virus) - genus and species, susceptibility/ resistance of infecting organisms, consider combination therapy

44
Q

what are host factors to consider

A

age, g6pd, history of allergy and ADR, pregnancy or lactation, renal or hepatic impairment, status of host immune function, severity of illness, recent abx use (past 6 months use), healthcare associated risk factors

45
Q

what are the benefits of combination therapy

A

extended spectrum of activity, achieve synergistic bactericidal effect, prevent development of resistance

46
Q

what are the disadvantages of combination therapy

A

increased risk of toxicity and allergic reactions, increased risk of DDI, increased cost, increased risk of superinfection, potential concern for antagonistic effect, selection of MDR bacteria

47
Q

what is the concern about use of abx in g6pd deficiency

A

hemolysis of RBC (breakdown) due to increase oxidative stress which decreases O2

48
Q

what are the drugs to avoid in g6pd deficiency

A

sulfonamides, nitrofurantoin, fluoroquinolones

49
Q

what are the drugs to avoid in kids

A

fluoroquinalones, tetracyclines

50
Q

what are the drugs that are safe and to avoid in pregnancy or lactation

A

safe: betalactam, macrolides
avoid: co-trimoxazole, fluoroquinolones, tetracyclines

51
Q

what are drugs to avoid for hepatic impairment

A

pyrazinamide, amoxicillin-clavulanate

52
Q

what are drugs to avoid for renal impairment

A

aminoglycosides, high dose vancomycin

53
Q

what are the drug factors to consider

A

activity against suspected organism, ability to reach site of infection, bactericidal vs bacteriostatic, PK PD, route of administration, side effect profile, drug interaction, cost, duration of use

54
Q

how to determine if an abx is bactericidal

A

MBC is within one 2-fold dilution of MIC

55
Q

what are some bactericidal antibiotics

A

beta lactams, aminoglycosides, fluoroquinolones, glycoproteins, lipopeptides, polymixins

56
Q

what are some bacteriostatic antibiotics

A

trimethoprim, sulfonamides, tetracyclines, macrolides

57
Q

what is the preferred route for abx

A

PO

58
Q

when is PO route not preferred

A

absorption problem, suitable abx not available in PO, high tissue conc essential, urgent treatment required, non compliant

59
Q

what are abx with good F

A

linezolid, co-trimoxazole, fluoroquinolone, metronidazole

60
Q

what is the PK PD target for beta lactams

A

fT > MIC for 40-70% of dosing interval
if critically ill or poor sites of penetration, fT > MIC for 50-100% of dosing interval

61
Q

what is the PK PD target for vancomycin

A

AUC24h/MIC 400-600

62
Q

what is the PK PD target for aminoglycosides

A

Cmax/MIC > 8-10x

63
Q

what is the PK PD target for fluoroquinolones

A

for gram pos, AUC/MIC >30
for gram neg, AUC/MIC >125, Cmax/MIC 8-12x

64
Q

what are the types of abx

A

conc dependent abx, time dependent abx (short half life), time dependent abx (long half life with PAE)

65
Q

what are the characteristics and dosing strategies of conc dependent abx

A

characteristics: rate and extend of killing as a function of abx conc, higher conc results in more rapid and more extensive bacterial killing

dosing strategy: optimise peak:MIC ratio 8-10, usually larger doses at extended intervals

66
Q

what are examples of conc dependent abx

A

aminoglycosides which has OD dosing as it has conc dependent bacterial killing and post abx effect (PAE), fluoroquinolone, daptomycin, metronidazole

67
Q

what are the benefits of OD dosing of aminoglycosides

A

less cost, less nephrotoxicity as allow drug to reach much lower conc until non detectable, prevents adaptive resistance

68
Q

when does adaptive resistance occur

A

occurs when always exposed to drug, prevents selection of more resistant mutants/ strains in body

69
Q

what are the characteristics and dosing strategies of time dependent abx with short half life

A

characteristics: rate and extent of bacterial killing are related to the amount of time the abx conc is above MIC of organism

dosing strategy: %T>MIC 40-70, more frequent administration either continuous IV or prolonged intermittent

70
Q

what is the role of probenecid

A

to block excretion of abx, useful for time dependent abx with short half life

71
Q

what are examples of time dependent abx with short half life

A

penicillin, cephalosporins, carbapenems, monobactams

72
Q

what is the characteristics and dosing strategy for time dependent abx with long half life/ PAE

A

characteristics: rate and extent of bacterial killing are related to overall drug exposure (AUC) vs MIC

dosing: optimise AUC: MIC ratio, dependent on total daily dose

73
Q

what are examples of time dependent abx with long half life/ PAE

A

vancomycin, clindamycin, macrolides, tetracyclines

74
Q

what are the PK drug interactions that may occur

A
  1. impaired absorption - fluoroquinolone chelates into divalent, antiacids can incr GI pH which decreases conc of abx that requires acidic pH, erythromycin has prokinetic effects which reduces oral absorption
  2. effects on hepatic metabolism - cyp inhibitors, inducers, substrates (3a4, 2c9, 1a2, 2c19)
  3. reduced excretion - probenecid competes for renal tubular excretion
75
Q

what are examples of cyp3a4 substrates

A

macrolides

76
Q

what are some examples of cyp3a4 inhibitors which can cause toxicity

A

azole, macrolides, anti HIV

77
Q

what are some examples of cyp3a4 inducers which can cause treatment failure

A

rifamycins

78
Q

what are the PD drug interactions that may occur

A
  1. additive/ aggravate toxicity potential through QT prolongation, nephrotoxicity, myelosuppression, photosensitivity, serotonergic syndrome
  2. alter intestinal flora (alter enterohepatic circulation of contraceptives, reduce production of vitamin K)
79
Q

what are the drugs that can cause QT prolongation

A

erythromycin, clarithromycin, fluoroquinolones, azoles

80
Q

what are the drugs that can cause nephrotoxicity

A

aminoglycosides, vancomycin, amphotericin B

81
Q

what are the drugs that can cause myelosuppression

A

co-trimoxazole, linezolid

82
Q

what are the drugs that can cause photosensitivity

A

sulfonamides, tetracyclines, quinolones

83
Q

what are the drugs that can cause serotonergic syndrome

A

linezolid

84
Q

what are the drugs that can alter intestinal flora

A

pencillin, tetracyclines, rifampicin

85
Q

what are the components when monitoring response

A

treatment goals, therapeutic response, adr, therapy modifications

86
Q

what are the treatment goals when monitoring response

A

achieve therapeutic response, minimal adr

87
Q

how do you monitor for therapeutic response

A

resolution/ reduction in signs and symptoms (objective and subjective), microbiological clearance, absence of complications or progressions

88
Q

when is therapy modifications necessary

A

when AST available (escalate or de escalate), satisfactory response (convert IV to PO or stop if completed adequate duration and patient is well), unsatisfactory response (reevaluate for possible causes)

89
Q

what are the causes of unsatisfactory response

A

inappropriate diagnosis (non infectious causes, non bacterial infection), inappropriate choice of agent, subtherapeutic concentration due to non compliance, impaired renal function, drug interactions, collections or abscess which requires surgery or drainage, impaired host defence, superinfection, toxicity of drug

90
Q

what is the general patient counselling points

A

this is an abx to treat xx infection, take xx capsules xx times a day about xx hours apart. take xx food, do not take together with xx, space xx hours apart. side effects may include xx. complete whole xx day course unless signs of allergy like rash, itch or swollen eyes, or if serious side effects occur. if allergy or any intolerable side effects occur, stop taking and see doctor immediately. you should feel better in 2-3 days if not please see your doctor. do remember to finish the course even if you feel better to ensure that infection is adequately treated

pr3151 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions