Rational Antimicrobial Selection Flashcards
1
Q
The initial selection of antimicrobial therapy may be ___, prior to documentation and identification of the offending organism.
A
Empirical
2
Q
Empirical antimicrobial therapy selection should be based on:
A
1) The patient’s history and physical examination
2) Results of Gram stains or other rapidly performed tests on specimens from the infected site
3) Knowledge of the most likely offending organism for the infection in question
4) Institution’s local microbial susceptibility patterns
3
Q
What are the most important factors in determining the choice of antimicrobial therapy?
A
1) Identification of the pathogen
2) Its antimicrobial susceptibility
4
Q
What are ‘infected materials’?
A
1) Blood
2) Sputum
3) Urine
4) Stool
5) Abscess, wound, or sinus drainage
6) Spinal fluid
7) Joint fluid
5
Q
Infected materials must be sampled BEFORE starting antimicrobial therapy for two reasons:
A
1) A Gram stain might reveal positive or negative stain bacteria, and an acid-fast stain might detect mycobacteria
2) The premature use of antimicrobials can suppress the growth of pathogens = false-negative cultures results.
6
Q
Blood cultures should be performed in which patient?
A
The acutely ill and febrile patient
7
Q
What should be done when a pathogenic microorganism is identified?
A
1) Antimicrobial susceptibility testing should be performed
2) Specific definitive antimicrobial therapy should be administered ASAP
8
Q
A variety of factors must be considered when selecting presumptive therapy:
A
1) The severity and acuity of the disease
2) Local epidemiology and antibiogram
3) Patient’s history and host factors
4) Factors related to the drug(s) to be used
5) The necessity for using multiple agents
9
Q
Are antibiotic susceptibilities the same or different across hospitals?
A
Different
10
Q
What is the most important part of the patient’s history when trying to find a suitable antibiotic?
A
The place where the infection was acquired
11
Q
____ can be exposed to potentially more resistant organisms because they are often surrounded by ill patients who are receiving antibiotics.
A
Nursing home patients
12
Q
Which host factors are taken into consideration when determining which antimicrobial to give?
A
1) Allergy
2) Age
3) Pregnancy
4) Metabolic or Genetic Variation
5) Organ Dysfunction
6) Concomitant Drugs
13
Q
Which drugs should be avoided in patients allergic to penicillin for immediate or accelerated reactions (anaphylaxis, laryngospasm)?
A
Cephalosporins
14
Q
Can we use Cephalosporins if a patient gets a mild rash when taking penicillins?
A
Yes
15
Q
Why is age an important host factor?
A
1) For identification of the likely etiologic agent
2) In the ability to eliminate the drug
16
Q
Which functions are NOT
well developed in neonates?
A
Hepatic and liver functions
17
Q
Neonates (especially when premature) can develop ___ when given sulfonamides.
A
Kernicterus
18
Q
Why can neonates (especially when premature) develop kernicterus when given sulfonamides?
A
Because of displacement of bilirubin from serum albumin
19
Q
The major change in the elderly is:
A
Decreased renal function
20
Q
Neonates (especially when premature) can develop kernicterus when given __.
A
Sulfonamides
21
Q
How are aminoglycosides excreted?
A
Renally
22
Q
The elderly has increased adverse effects of which antimicrobials?
A
Those eliminated by the kidney
23
Q
During pregnancy, the fetus is at risk of:
A
Drug teratogenicity
24
Q
Which drugs are cleared more rapidly during pregnancy?
A
1) Penicillins
2) Cephalosporins
3) Aminoglycosides
25
Why are certain drugs cleared more rapidly during pregnancy?
Because of increases in:
1) Intravascular volume
2) GFR
3) Hepatic metabolic activities
26
The maternal serum antimicrobial concentrations are ~ 50% __(higher/lower) than in the nonpregnant state.
Lower
27
__(Decreased/Increased) dosages of certain compounds might be necessary to achieve therapeutic levels during late pregnancy.
Increased
28
Patients with impaired blood flow may NOT absorb drugs given by ___ well.
Intramuscular injection
29
What will influence therapy of infectious diseases in a variety of ways?
Inherited or acquired metabolic abnormalities
30
Patients who are slow acetylators of __ are at greater risk for peripheral neuropathy
Isoniazid
31
Patients who are slow acetylators of isoniazid are at greater risk for ___.
Peripheral neuropathy
32
Patients with severe deficiency of ___ can develop significant hemolysis when exposed to dapsone, sulfonamides, nitrofurantoin, nalidixic acid, and antimalarials.
Glucose-6-phosphate dehydrogenase
33
Patients with severe deficiency of glucose-6-phosphate dehydrogenase can develop
significant hemolysis when exposed to which drugs?
1) Dapsone
2) Sulfonamides
3) Nitrofurantoin
4) Nalidixic acid
5) Antimalarials
34
Which antiretroviral drug is associated with severe hypersensitivity reaction (fever, rash, abdominal pain, and respiratory distress) in the presence of human leukocyte antigen allele HLAB*5701?
Abacavir
35
The antiretroviral drug Abacavir is associated with severe hypersensitivity reaction (fever, rash, abdominal pain, and respiratory distress) in the presence of:
Human leukocyte antigen allele HLAB*5701
36
Which antibiotics should be adjusted in severe liver disease?
1) Clindamycin
2) Erythromycin
3) Metronidazole
4) Rifampin
37
Significant accumulation can occur when both liver and renal dysfunction are present for which drugs?
1) Nafcillin
2) Sulfamethoxazole
3) Cefotaxime
4) Piperacillin
38
Administration of Isoniazid with phenytoin can result in phenytoin toxicity due to:
Inhibition of Phenytoin metabolism by Isoniazid
39
Administration of Isoniazid with Phenytoin can result in __ toxicity.
Phenytoin
40
Drugs that possess similar adverse effect profiles can produce ___ adverse effects.
Enhanced
41
Which drugs are aminoglycosides?
1) Gentamicin
2) Amikacin
3) Tobramycin
4) Neomycin
5) Streptomycin
42
Aminoglycosides have major drug interactions with:
1) Neuromuscular blocking agents
2) Nephro- and Oto-toxins
43
What happens if you give aminoglycosides with Neuromuscular blocking agents?
Additive NMJ block
44
Which drugs are nephro and oto toxic?
1) Amphotericin
2) Cisplatin
3) Cyclosporine
4) Furosemide
5) NSAIDs
6) Radiocontrast media
7) Vancomycin
45
Amphotericin B has major drug interactions with:
Nephrotoxins such as:
1) Aminoglycosides
2) Cidofovir
3) Cyclosporine
4) Foscarnet
5) Pentamidine
46
Chloramphenicol decreases metabolism of:
1) Phenytoin
2) Tolbutamide
3) Ethanol
47
Foscarnet given with ___ increases risk of severe nephrotoxicity/hypocalcemia.
Pentamidine IV
48
Foscarnet given with Pentamidine IV increases risk of:
Severe nephrotoxicity/hypocalcemia
49
Isoniazid decreases metabolism of:
1) Carbamazepine
2) Phenytoin
50
Isoniazid given with Carbamazepine/Phenytoin can cause:
1) Nausea
2) Vomiting
3) Nystagmus
4) Ataxia
51
Why shouldn't Macrolides/azalides be given with Digoxin?
Increased Digoxin bioavailability
52
Macrolides/azalides should NOT be given with:
Digoxin
53
Metronidazole with ethanol (drugs containing ethanol) cause:
Disulfiram-like reaction
54
Metronidazole should not be given with ___ because of disulfiram-like reaction.
Ethanol (drugs containing ethanol)
55
Penicillins/Cephalosporins should NOT be given with:
1) Probenecid
2) Aspirin
56
Why should Penicillins/Cephalosporins NOT be given with Probenecid or Aspirin?
Blocked excretion of β-lactams
57
Quinolones have major drug reactions with:
1) Classes Ia and III antiarrhythmics
2) Multivalent cations (antacids, iron, sucralfate, zinc, vitamins, dairy products)
3) Citric acid
4) Didanosine
58
What happens if you give Quinolones with Classes Ia and III antiarrhythmics?
Increased QT interval
59
What happens if you give Quinolones with Multivalent cations (antacids, iron, sucralfate, zinc, vitamins, dairy products), Citric acid, or Didanosine?
Decreased absorption of Quinolones
60
Rifampin increases metabolism of:
1) Azoles
2) Cyclosporine
3) Oral contraceptives
4) Warfarin
5) Protease inhibitors
6) Methadone
7) Tacrolimus
8) Propranolol
61
Sulfonamides should not be given with:
1) Sulfonylureas
2) Phenytoin
3) Warfarin
62
Sulfonamides given with Sulfonylureas, Phenytoin, or
Warfarin cause:
Displacement from binding to albumin
63
Tetracyclines have major drug reactions with:
1) Antacids
2) Iron
3) Calcium
4) Sucralfate
5)Digoxin
64
Tetracyclines given with Antacids, iron, calcium, or sucralfate cause:
Decreased absorption of tetracycline.
65
Tetracyclines given with Digoxin cause:
Increased digoxin bioavailability
66
Important drug parameters to be considered are the:
1) Minimal Inhibitory Concentration (MIC)
2) Time the concentration is above MIC
67
Aminoglycosides exhibit ______, which allows a once-daily aminoglycosides administration.
Concentration-dependent bactericidal effects
68
Which drugs are given as a single large daily dose to maximize the peak/MIC ratio?
Aminoglycosides
69
Aminoglycosides possess a what kind of effect?
Post-antibiotic
70
What is the Post-antibiotic effect?
Persistent suppression of organism growth after concentrations decrease below the MIC
71
What appears to contribute to the success of high-dose, once-daily administration of aminoglycosides?
Post-antibiotic effect
72
Fluoroquinolones exhibit:
Concentration-dependent killing activity
73
Optimal killing by Fluoroquinolones appears to be characterized by:
The AUC/MIC ratio
74
β-Lactams display ___ effects.
Time-dependent bactericidal
75
The important pharmacodynamic relationship for β-Lactams is:
The duration that drug concentrations exceed the MIC
76
How can you administer β-lactams in ways that appear to be correlated with positive outcomes?
1) Frequent small doses
2) Continuous infusion
3) Prolonged infusion
77
One important factor in treating an infection is:
The presence of the antimicrobial agent in an **active form** and at **adequate concentration** at the site of infection
78
Drugs that have low biliary fluid concentrations are NOT useful in the treatment of:
1) Cholecystitis
2) Cholangitis
79
Drugs that do NOT reach significant concentrations in the CSF should NOT be used in
treatment of:
Bacterial meningitis
80
Which factors can high
concentrations of certain drugs?
1) Acidic pH
2) WBC products
3) Various enzymes
81
Body fluids where drug concentration data are
clinically relevant include:
1) CSF
2) Urine
3) Synovial fluid
4) Peritoneal fluid
82
Parenteral therapy is indicated in:
1) Febrile neutropenia
2) Meningitis
3) Endocarditis
4) Osteomyelitis
83
Severe pneumonia often is treated initially with __(oral/IV) antibiotics then switched to __(oral/IV) therapy with clinical improvement.
IV; Oral
84
Which patient illnesses treated in the ambulatory setting can receive oral therapy?
1) URTIs (pharyngitis,
bronchitis, sinusitis, and otitis media)
2) Lower respiratory tract infections
3) Skin and soft-tissue
infections
4) Uncomplicated UTIs
5) Selected STDs
85
Antibiotics associated with CNS toxicities, when not dose-adjusted for renal function, include:
1) Penicillins
2) Cephalosporins
3) Quinolones
4) Imipenem
86
Reversible nephrotoxicity is classically associated with:
1) Aminoglycosides
2) Vancomycin
87
Irreversible ototoxicity can occur with:
Aminoglycosides
88
Hematologic toxicities occur with prolonged use of:
1) **N**afcillin (**N**eutropenia)
2) **P**iperacillin (**P**latelet
dysfunction)
3) Cefotetan (Hypoprothrombinemia)
4) Chloramphenicol (Bone marrow suppression, both idiosyncratic and dose-related toxicity)
5) Trimethoprim (Megaloblastic anemia)
89
Prolonged use of Nafcillin causes:
Neutropenia
90
Prolonged use of Piperacillin causes:
Platelet dysfunction
91
Prolonged use of Cefotetan causes:
Hypoprothrombinemia
92
Prolonged use of Chloramphenicol causes:
Bone marrow suppression
93
Prolonged use of Trimethoprim causes:
Megaloblastic anemia
94
Which drugs cause photosensitivity?
1) Azithromycin
2) Quinolones
3) Tetracyclines
4) Pyrazinamide
5) Sulfamethoxazole
6) Trimethoprim
95
Many antibiotics have been implicated in causing
diarrhea and colitis secondary to ___ superinfection!!!!!!
Clostridium difficile
96
Which drugs cause QT prolongation?
1) Macrolides/azalide
2) Fluoroquinolones
97
Which drugs cause Stevens-Johnson syndrome?
1) Fluoroquinolones
2) Sulfonamides and trimethoprim
98
Patients who fail to respond to antimicrobial therapy over 2-3 days require:
A thorough reevaluation
99
Causes of antimicrobial therapy failure?
1) The disease is NOT infectious or is nonbacterial in origin
2) There is an undetected pathogen in a polymicrobial infection
3) Factors directly related to drug selection, the host, or the pathogen
4) Laboratory error in identification, susceptibility testing, or both
100
Antimicrobial therapy failures caused by Drug Selection?
1) Inappropriate selection of drug, dosage, or route of administration
2) Reduced absorption of a drug, resulting in subtherapeutic concentrations
3) Accelerated drug elimination = low concentrations
4) Poor penetration into the site of infection
5) Chemical inactivation of the drug at the site of infection
101
Which "diseases" can cause accelerated drug elimination?
1) Cystic fibrosis
2) Pregnancy
102
Which sites have poor penetration into the site of infection?
1) CNS
2) Eye
3) Prostate gland
103
Reduced absorption of a drug, resulting in subtherapeutic concentrations, can be caused by:
1) GI disease (short-bowel syndrome)
2) Drug interactions
104
Antimicrobial therapy failures caused by Host Factors?
1) Immunosuppression
2) The need for surgical drainage of abscesses or removal of foreign bodies, necrotic tissue, or both.
105
Which infections will NOT be effectively treated without surgical procedures?
1) Abscesses
2) Removal of foreign bodies, necrotic tissue, or both.
106
What is Intrinsic resistance?
When the antimicrobial agent never had activity against the bacterial species. (Naturally resistant)
107
Bacteria that lack ___ will not respond to βlactam antibiotics.
Cell wall
108
What is Acquired resistance?
When the antimicrobial agent was originally active against the bacterial species but the genetic makeup of the bacteria has changed so the drug can NO longer be effective.
109
What are the mechanisms of acquired bacterial resistance?
1) Alteration in the target site
2) Change in membrane permeability
3) Expression of an efflux pump
4) Drug inactivation through either β-lactamases or aminoglycoside-modifying enzymes is the predominant mechanism of resistance!!
110
The expression of β-lactamases can be:
1) Induced
2) Constitutive
111
The increased resistance results from:
1) Continued overuse of antimicrobials in the community and in hospitals
2) Long-term suppressive antimicrobials for the prevention of infections in immunosuppressed patients
112
Enterococci with multiple resistance patterns may be resistant to:
1) β-lactams
2) Vancomycin
3) Aminoglycosides
4) Tetracyclines
5) Ciprofloxacin
6) Clindamycin
7) Erythromycin
8) Quinupristin-dalfopristin
113
Resistance to β-lactams can be caused by:
1) β-lactamase production
2) Altered penicillin-binding proteins [PBPs]
3) Both
114
Resistance to Vancomycin can be caused by:
Alterations in peptidoglycan synthesis
115
Resistance to Aminoglycosides can be caused by:
High levels of AGs-degrading enzymes
116
Penicillin-Resistant Enterococci treatment?
Vancomycin + Gentamicin or Streptomycin
117
Vancomycin-Resistant Enterococci (VRE) treatment?
1) Linezolid
2) Daptomycin
3) Tigecycline
4) Nitrofurantoin for UTI
118
Enterococci with multiple resistance patterns treatment are susceptible to:
1) Imipenem
2) Teicoplanin
119
Resistant Pneumococci are usually susceptible to:
1) Vancomycin
2) New Fluoroquinolones:
a) Moxifloxacin
b) Trovafloxacin)
3) Cefotaxime/Ceftriaxone
120
Which antimicrobial agents have been used for resistant gram-positive bacteria?
1) Linezolid
2) Daptomycin
3) Telavancin (Semi-synthetic
derivative of Vancomycin)
4) Tigecycline (New Tetracycline)
121
Enterobacter, Citrobacter, Serratia, and P. aeruginosa usually retain susceptibility to:
1) Fluoroquinolones
2) Aminoglycosides
3) Carbapenems
122
Which patients are at high risk for drug failure?
Debilitated patients with:
1) Pulmonary infections
2) Abscesses
3) Osteomyelitis
123
True or False: Antimicrobial combinations are often overused in clinical practice.
TRUE
124
The unnecessary use of antimicrobial combinations may cause:
1) Increases toxicity
2) Increases costs
3) Reduced efficacy due to antagonism of one drug by another
125
Antimicrobial combinations should be selected for one or more of the following reasons:
1) To provide broad-spectrum empiric therapy in seriously ill patients.
2) To treat polymicrobial infections
3) To decrease the emergence of resistant strains–tuberculosis.
4) To obtain enhanced inhibition or killing
5) To decrease dose-related toxicity by using reduced doses of one or more components of the drug regimen.
126
Antimicrobial combinations chosen should cover:
The most common known or suspected pathogens but NOT cover all possible pathogens.
127
The use of Flucytosine in combination with Amphotericin B for the treatment of Cryptococcal meningitis in non HIV-infected patients allows for:
A reduction in amphotericin B dosage with decreased Amphotericin B induced nephrotoxicity
