What are the 5 Ds of antimicrobial stewardship?

Diagnosis, Drug, Dose, Duration, De-escalation

What’s a major factor affecting the reliability of MIC interpretation?

Drug concentration at infection site

What does “susceptible dose dependent” (SDD) mean?

Higher or aggressive dosing is needed

Which gram-negative bacilli are aerobic, non-lactose fermenting, and oxidase negative?

Proteus, Salmonella, and Acinetobacter

When is antimicrobial combination therapy typically used?

Serious infections and polymicrobial cases

What lab test helps determine if a specific antibiotic is effective against a pathogen?

Antimicrobial susceptibility testing

Which organism is a common gram-negative rod found in the oral cavity?

Bacteroides spp. (non-fragilis)

Which antibiotics are concentration-dependent with Cmax:MIC relevance?

Aminoglycosides, fluoroquinolones, daptomycin

What organization establishes MIC breakpoints?

Clinical and Laboratory Standards Institute

Which classification best fits Escherichia coli and Klebsiella pneumoniae?

Aerobic, lactose fermenting, oxidase negative

How does impaired vascular flow affect antibiotic therapy?

Prevents drug from reaching infection site

What is the dosing strategy for concentration-dependent killing antibiotics?

Large doses with decreased frequency

Why may pregnant patients require higher antibiotic doses?

Increased volume of distribution and clearance

Which drugs exhibit AUC:MIC–based killing?

Macrolides, vancomycin, fluoroquinolones

What is one common clinical pitfall when using MIC data?

Comparing MICs of different organisms

What is the purpose of maintaining drug concentration above MIC for as long as possible?

Enhances bacterial killing in time-dependent drugs

Why were penicillinase-resistant penicillins developed?

To overcome penicillinase-producing staph

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Answers

1
What are the 5 Ds of antimicrobial stewardship?
Drug, Disease, De-escalation, Diet
Diagnosis, Drug, Dose, Duration, De-escalation
Diagnosis, Direction, Design, Duration, Discharge
Direction, Drug, Distribution, Dose, Delay
2
What is the main route of elimination for natural penicillins?
Biliary
Hepatic
Fecal
Renal
3
What is the dosage form of Penicillin G (benzylpenicillin)?
PO
SC
IM
IV
4
What’s a major factor affecting the reliability of MIC interpretation?
Platelet count
Enzyme inhibition
Serum protein levels
Drug concentration at infection site
5
What group of bacteria are aerobic, non-lactose fermenting, and oxidase positive?
Pseudomonas and Campylobacter
Haemophilus and Burkholderia
Escherichia and Shigella
Vibrio and Salmonella
6
What does pharmacodynamics describe?
How the immune system responds
Drug transport in the body
What the body does to the drug
What the drug does to the bug
7
What does “susceptible dose dependent” (SDD) mean?
MIC value changes with fluid volume
MIC may fluctuate based on age
Higher or aggressive dosing is needed
Susceptibility depends on testing lab
8
What type of therapy is chosen after identification of the causative organism?
Directed
Empiric
Prophylactic
De-escalation
9
Which organism causes syphilis and belongs to the spirochete class?
Chlamydia trachomatis
Borrelia burgdorferi
Mycoplasma pneumoniae
Treponema pallidum
10
Which gram-negative bacilli are aerobic, non-lactose fermenting, and oxidase negative?
Proteus, Salmonella, and Acinetobacter
Campylobacter, Haemophilus, and Vibrio
Klebsiella, Enterobacter, and Serratia
Bacteroides, Prevotella, and Fusobacterium
11
When is antimicrobial combination therapy typically used?
Prophylaxis for surgery
Topical infections
Serious infections and polymicrobial cases
Mild outpatient infections
12
Which agency provides guidance on core elements of antimicrobial stewardship programs?
CDC
FDA
NIH
CMS
13
What test uses fluorescence-based molecular hybridization for rapid pathogen ID in about 90 minutes?
Microbroth dilution
Accelerate PhenoTest™ BC Kit
PCR multiplex panel
MALDI-TOF
14
Are timed-kill curve tests commonly performed in clinical labs?
Only in pediatric cases
Only for resistant organisms
Yes
No
15
What lab test helps determine if a specific antibiotic is effective against a pathogen?
Gram stain
Complete blood count
Liver function panel
Antimicrobial susceptibility testing
16
Which bacteria can cause CNS infections and are gram-negative cocci?
Haemophilus influenzae
Neisseria meningitidis
Escherichia coli
Enterobacter spp.
17
Which formulation provides blood levels up to 7 days and is used for pneumonia and syphilis?
PCN G benzathine
PCN G procaine
PCN G IV aqueous
PCN VK
18
What does it mean when two drugs combined have more effect than either alone?
Resistance
Indifference
Synergy
Antagonism
19
Which organism is a common gram-negative rod found in the oral cavity?
Klebsiella pneumoniae
Haemophilus influenzae
Bacteroides spp. (non-fragilis)
Pseudomonas aeruginosa
20
Which drug has a resistant interpretation with MIC ≥8 in Staphylococcus testing?
Oxacillin
Rifampin
Ciprofloxacin
Erythromycin
21
Which gram-negative bacillus is both non-lactose fermenting and oxidase negative?
Stenotrophomonas maltophilia
K. aerogenes
Pasteurella multocida
Haemophilus influenzae
22
Which gram-negative bacillus is oxidase positive but does NOT ferment lactose?
Klebsiella pneumoniae
Escherichia coli
Pseudomonas aeruginosa
Citrobacter freundii
23
Linezolid belongs to which category based on its activity?
Antifungal
Bacteriostatic
Antiviral
Bactericidal
24
What type of fungi are Histoplasma, Blastomyces, and Coccidioides?
Moulds
Dimorphic fungi
Yeasts
Anaerobic fungi
25
Which antibiotics are concentration-dependent with Cmax:MIC relevance?
Tetracyclines and sulfonamides
Vancomycin and fosfomycin
Aminoglycosides, fluoroquinolones, daptomycin
Penicillins and cephalosporins
26
Which natural penicillin is available orally?
Penicillin VK
Penicillin G benzathine
Penicillin G procaine
Penicillin G
27
Why is Penicillin G not given orally?
Liver metabolism destroys it
Unstable in gastric acid
Low bioavailability
Poor absorption in small intestine
28
What organization establishes MIC breakpoints?
Centers for Disease Control
Clinical and Laboratory Standards Institute
World Health Organization
Infectious Diseases Society
29
What route is preferred for Penicillin G in severe infections?
IM aqueous
IV aqueous
Oral
Subcutaneous
30
What is the dosage form of dicloxacillin?
PO
IV
IM
SubQ
31
Which classification best fits Escherichia coli and Klebsiella pneumoniae?
Aerobic, oxidase negative
Anaerobic, oxidase positive
Aerobic, lactose fermenting, oxidase negative
Aerobic, lactose negative, oxidase positive
32
Which of the following is a gram-negative bacillus that ferments lactose?
Proteus mirabilis
Salmonella spp.
Escherichia coli
Pseudomonas aeruginosa
33
How does impaired vascular flow affect antibiotic therapy?
Enhances antibiotic potency
Promotes resistance
Increases drug excretion
Prevents drug from reaching infection site
34
Are Clostridium spp. (excluding C. difficile) covered by natural penicillin?
Yes
Only anaerobic species
No
Only during co-infection
35
What is the dosing strategy for concentration-dependent killing antibiotics?
Small frequent doses
Large doses with decreased frequency
Continuous infusion
IV push every 6 hours
36
What anaerobic gram-negative cocci is listed in the classification?
Veillonella spp.
Fusobacterium spp.
Moraxella catarrhalis
Bacteroides fragilis
37
Why may pregnant patients require higher antibiotic doses?
Impaired fetal circulation
Increased volume of distribution and clearance
Decreased renal clearance
Decreased hepatic metabolism
38
What is the drug of choice for Treponema pallidum (syphilis)?
Penicillin G
Penicillin VK
Amoxicillin
Ceftriaxone
39
Which drugs exhibit AUC:MIC–based killing?
β-lactams and sulfonamides
Cephalosporins and glycopeptides
Penicillins and carbapenems
Macrolides, vancomycin, fluoroquinolones
40
What is one common clinical pitfall when using MIC data?
Always using high-dose antibiotics
Avoiding empiric therapy
Comparing MICs of different organisms
Substituting oral for IV automatically
41
What is the purpose of maintaining drug concentration above MIC for as long as possible?
Enhances bacterial killing in time-dependent drugs
Reduces dosing frequency
Minimizes cost
Improves tissue penetration
42
What qualitative method uses paper disks to test bacterial susceptibility on agar?
Kirby-Bauer disk diffusion
Etest
Morphokinetic testing
MIC dilution method
43
Which of the following is a bactericidal antibiotic?
Tetracyclines
Clindamycin
Aminoglycosides
Linezolid
44
What MIC method analyzes single-cell growth microscopically every 10 minutes?
Epsilometer test
Microbroth dilution
Macrobroth dilution
MCA
45
Why is Staphylococcus spp. not covered by natural penicillin?
Biofilm formation
Lack of PBPs
> 90% penicillinase production
High resistance to β-lactams
46
What gram-negative cocci is associated with respiratory tract infections?
Bacteroides spp.
Prevotella spp.
Moraxella catarrhalis
Neisseria meningitidis
47
Which protein do penicillins bind to for their effect?
Peptidoglycan synthase
Topoisomerase
Penicillin-binding protein
Beta-lactamase
48
What is the pregnancy risk category for natural penicillins?
Unknown
Moderate risk
High risk
Low risk
49
What drug factor must be reviewed to avoid hypersensitivity reactions?
MIC and breakpoints
Allergies
Route of administration
Cost considerations
50
Why were penicillinase-resistant penicillins developed?
To overcome penicillinase-producing staph
To avoid renal toxicity
To treat gram-negative bacteria
To treat viral meningitis
51
What spirochete is associated with Lyme disease?
Treponema pallidum
Leptospira interrogans
Borrelia burgdorferi
Mycobacterium marinum
52
What is the interpretation of vancomycin with an MIC of 1 in Staphylococcus spp.?
SD
I
S
R
53
In the antagonism graph, how does the combination therapy (A + C) perform compared to Drug A?
No difference
It is equally effective
It is more effective
It is less effective
54
Which PCN formulation is not used for syphilis or pneumococcal meningitis?
PCN G procaine only
PCN G IV
PCN G procaine and benzathine
PCN VK
55
Which method is considered more consistent or accurate than standard methods, especially for new drugs?
Epsilometer test
MCA
Microbroth dilution
Macrobroth dilution
56
Why is the site of infection important when selecting an antimicrobial?
Determines liver metabolism
Correlates with drug penetration and efficacy
Predicts side effects
Avoids cross-reactivity
57
How is MIC determined in an Epsilometer test (Etest)?
Lowest visible turbidity
Edge of the strip
Bottom of the elliptical zone of inhibition
Diameter of clearing
58
Are penicillinase-resistant penicillins safe in pregnancy?
Only in third trimester
No
Yes, routinely used
Only with folic acid
59
What pharmacodynamic parameter is most relevant to timed-kill testing for β-lactams?
MIC90
AUC/MIC
Cmax/MIC
fT>MIC
60
What is the mechanism of action of antistaphylococcal penicillins?
Inhibits DNA replication
Blocks folate production
Binds to ribosomes
Inhibits cell wall synthesis
61
What is a key drug interaction of penicillinase-resistant penicillins?
Alters protein binding
CYP1A2 inhibition
Induces warfarin metabolism
Enhances statin toxicity
62
Which fungi are classified as moulds?
Candida and Cryptococcus
Aspergillus, Rhizopus, Mucor, Rhizomucor
Histoplasma and Blastomyces
Coccidioides and Candida
63
Which factors are included when considering drug cost?
Time of onset
Liver enzyme levels
Drug name only
Frequency, administration route, monitoring
64
Which organisms are classified as anaerobic gram-negative bacilli?
Prevotella, Bacteroides, Fusobacterium
Acinetobacter, Klebsiella, E. coli
Haemophilus, Proteus, Providencia
Veillonella, Moraxella, Neisseria
65
What are the common side effects of this class?
Seizures and hives
Cholestatic hepatitis, interstitial nephritis, GI
Rash only
Liver cirrhosis
66
What is the interpretation for cefepime with MIC ≤1.0 in the E. coli susceptibility chart?
NI
SD
SS
R
67
What is the AUC:MIC goal for vancomycin?
200–300
400–600
600–800
100–200
68
What is de-escalation in antimicrobial therapy?
Broadening coverage
Narrowing therapy based on cultures
Stopping treatment early
Starting prophylaxis
69
Which of the following fluids or tissues does penicillin distribute into?
Retina, cornea, vitreous
Sweat, aqueous humor, lymph
Blister fluid, lung, bile
CSF in healthy patients only
70
What is post-antibiotic effect (PAE)?
Bacterial regrowth delay post-antibiotic
Enzyme inhibition
Resistance to bacteriostatic drugs
Drug accumulation in tissue
71
What does it mean when an antibiotic is bactericidal?
It disrupts host immune responses
It kills susceptible bacteria
It slows replication
It suppresses bacterial growth
72
What does prolonged infusion aim to improve in time-dependent antibiotics?
Maximizes PAE
Increases fT>MIC
Increases Cmax
Reduces resistance development
73
Which group of gram-negative bacilli are anaerobic?
Salmonella, Shigella, and Morganella
Klebsiella and Enterobacter
Vibrio and Pasteurella
Bacteroides, Prevotella, Fusobacterium
74
What does a zone of inhibition in Kirby-Bauer testing correlate with?
Spectrum of activity
Dose-dependent killing
Genetic resistance
Minimum inhibitory concentration
75
Which MIC method uses test tubes with two-fold dilutions and is rarely used in labs due to being cumbersome?
Macrobroth dilution
Epsilometer test
Morphokinetic cellular analysis
Microbroth dilution
76
What is the mechanism of action for natural penicillins?
Inhibit cell wall synthesis
Disrupt DNA synthesis
Bind ribosomal subunits
Inhibit protein synthesis
77
Who provides oversight of stewardship programs in healthcare settings?
FDA and DEA
CDC and WHO
AMA and ASHP
Joint Commission and CMS
78
What age-related factor can increase the risk of drug toxicities in neonates and elderly?
Increased metabolism
Enhanced immunity
Increased protein binding
Decreased renal clearance
79
How should recurrent infection after recent drug use be treated?
Use a drug from the same class
Treat with an alternative agent
Increase the dose
Discontinue antibiotics
80
What pathogens commonly infect the abdomen and include both aerobes and anaerobes?
Klebsiella and Neisseria
Listeria and Moraxella
Clostridium spp. and Bacteroides spp.
Proteus and Haemophilus
81
Which atypical bacteria are involved in lower respiratory tract infections?
Bacillus and Actinomyces spp.
Klebsiella and Pseudomonas spp.
Listeria and Neisseria spp.
M. pneumoniae, C. pneumoniae, L. pneumophila
82
What is the general purpose of a susceptibility report?
Rule out gram stain
Confirm MIC breakpoints
De-escalate or target antibiotic therapy
Determine organism shape
83
Which PK/PD target is most improved by continuous infusion strategies?
fT>MIC
AUC:MIC
PAE
Cmax
84
Which route would be appropriate for severe infections needing rapid drug levels?
Intravenous
Oral
Intramuscular
Subcutaneous
85
Polymyxin E is classified as what type of antibiotic?
Antiviral
Bacteriostatic
Bactericidal
Antifungal
86
What is a “susceptible” MIC interpretation?
Requires resistant strains
No treatment success possible
Works using standard antimicrobial doses
Only works at high dose
87
What acid-fast bacilli are part of the MAC (Mycobacterium avium complex)?
Mycobacterium kansasii and marinum
Mycobacterium leprae and tuberculosis
Mycobacterium intracellulare and avium
Mycobacterium bovis and africanum
88
What does Cmax/MIC represent in pharmacodynamics?
Duration of activity
Total exposure over time
Peak drug exposure vs. susceptibility
Immune cell activation
89
Which sites are difficult for antimicrobials to penetrate?
Skin and GI tract
CNS, prostate, bone, biliary tract
Liver and spleen
Lungs and kidneys
90
What is the spectrum of activity for natural penicillins?
Broad gram-negative only
Mostly fungal
Good gram-positive, limited gram-negative
Only anaerobic and atypicals
91
Which gram-negative rods are common in urinary tract infections?
Escherichia coli, Klebsiella, Proteus
Pseudomonas and Haemophilus
Campylobacter and Bacteroides
Salmonella and Shigella
92
Which drug factor considers gram-positive vs. gram-negative activity?
MIC
Spectrum of activity
Route of administration
Cost
93
What is the seizure risk increased by during PCN therapy?
Low dose use only
Single-dose oral therapy
IV route in healthy adults
Renal impairment and high dose
94
Which gram-negative bacilli are aerobic, lactose fermenting, and oxidase negative?
Klebsiella and Escherichia
Vibrio and Pasteurella
Pseudomonas and Burkholderia
Bacteroides and Fusobacterium
95
Which spirochete is treated with natural penicillin?
Borrelia burgdorferi
Mycoplasma pneumoniae
Treponema pallidum
Leptospira interrogans
96
What does MIC90 represent?
MIC value that inhibits 90% of organisms in a test population
Breakpoint for oral agents
Dose needed to inhibit toxicity
Concentration for resistance cutoff
97
What does antagonism mean in the context of combination therapy?
Better than either agent
Same as either agent
No change in effect
Worse than either agent
98
Which drug classes have long PAE against gram-negative organisms?
DNA and protein synthesis inhibitors
β-lactams
Cell wall inhibitors
Folic acid antagonists
99
Which agents are examples of drugs with SDD interpretation?
Amoxicillin and metronidazole
Cefepime, fluconazole, daptomycin
Nitrofurantoin and trimethoprim
Vancomycin and linezolid
100
What is the purpose of breakpoints in susceptibility testing?
Measure drug cost
Predict patient adherence
Define bacterial colony size
Interpret MIC to guide therapy
101
What is the main route of elimination for nafcillin and oxacillin?
Lymphatic
Renal
Hepatic and biliary
Fecal
102
Which gram-negative cocci are covered by natural penicillins?
Neisseria meningitidis
Moraxella catarrhalis
Haemophilus influenzae
Klebsiella pneumoniae
103
Which organisms are categorized as anaerobic gram-negative bacilli?
Proteus and Providencia
Bacteroides, Prevotella, Fusobacterium
Enterobacter and Citrobacter
Campylobacter and Haemophilus
104
What is the dosage form for Bicillin C-R® (Penicillin G procaine and benzathine)?
IV
PO
SubQ
IM
105
What is a unique characteristic of Burkholderia cepacia among gram-negative bacilli?
It is oxidase positive but non-fermenting
It is acid-fast
It is a spore-former
It is gram-positive under certain conditions
106
What is the term for using antibiotics to reduce the risk of infection?
Prophylaxis
Directed therapy
De-escalation
Empiric therapy
107
Which class of antibiotics includes vancomycin and oritavancin?
Both
Neither
Bactericidal
Bacteriostatic
108
What method uses well plates with two-fold dilutions to determine MICs more efficiently?
Disk diffusion
Microbroth dilution
Macrobroth dilution
MCA
109
Which anaerobic gram-negative organism is non-fragilis?
Bacteroides spp. (non-fragilis)
Veillonella spp.
Bacteroides fragilis
Fusobacterium spp.
110
What do timed-kill curve tests evaluate?
Antimicrobial effect on bacteria
Host immune response
Resistance mutation
Drug metabolism in the liver
111
Which penicillinase-resistant penicillin is no longer available in the U.S.?
Dicloxacillin
Methicillin
Oxacillin
Nafcillin
112
Which of the following is both lactose fermenting and part of the Enterobacterales order?
Klebsiella oxytoca
Pseudomonas aeruginosa
Haemophilus influenzae
Acinetobacter spp.
113
How can hepatic function in neonates affect drug therapy?
Increases absorption
Enhances drug elimination
Improves liver regeneration
Decreases metabolism, leading to toxicity
114
Which gram-positive cocci commonly infect skin and soft tissue?
Streptococcus pneumoniae
Peptostreptococcus spp.
Enterococcus faecalis
Staphylococcus aureus and pyogenes
115
What does MIC stand for?
Most inhibitory compound
Minimum inhibitory concentration
Microbial infection concentration
Maximum infectivity category
116
What factors are included in PK/PD evaluation?
MIC and MBC
Bacterial resistance
Drug-drug interactions and ADME
Cost and convenience
117
Which acid-fast bacillus causes tuberculosis?
Mycobacterium leprae
Mycobacterium marinum
Nocardia spp.
Mycobacterium tuberculosis
118
Which gram-negative organism is listed under natural penicillin coverage?
Proteus mirabilis
E. coli
Pseudomonas aeruginosa
Pasteurella multocida
119
Why can altered pH in neonates or elderly impact antimicrobial therapy?
Inhibits immune response
Impacts antimicrobial absorption
Delays gastric emptying
Alters enzyme binding
120
Which bacteria are classified as HACEK organisms?
Haemophilus spp., Aggregatibacter, Cardiobacterium, Eikenella, Kingella
Salmonella, Shigella, Morganella
Klebsiella, Enterobacter, Citrobacter
Escherichia coli, Proteus spp.
121
Which of these antibiotics is bacteriostatic?
Chloramphenicol
Metronidazole
Fluoroquinolones
Carbapenems
122
Why is site of infection important when selecting a drug?
It determines resistance mechanism
It changes the organism’s susceptibility
It avoids hypersensitivity
It affects drug penetration
123
Which two organisms are both aerobic and lactose fermenting with oxidase positivity?
Klebsiella and Citrobacter
Pseudomonas and Salmonella
Vibrio and Pasteurella
Proteus and Providencia
124
Which of the following antibiotics is NOT bactericidal?
Daptomycin
Glycyclines
Monobactams
Penicillins
125
Which infusion strategy produces the highest drug peak concentration?
Traditional bolus infusion
Oral dosing
Continuous infusion
Prolonged infusion
126
What is the goal peak-to-MIC ratio (Cmax:MIC) for concentration-dependent antibiotics?
≥ 5
≥ 2
≥ 10
≥ 20
127
Which bacteria are only partially acid-fast?
Nocardia spp.
Treponema pallidum
Mycobacterium kansasii
Mycoplasma spp.
128
Which two species of Neisseria are clinically significant pathogens?
Neisseria sicca and flavescens
Neisseria and Veillonella
Neisseria and Moraxella
Neisseria gonorrhoeae and meningitidis
129
What is the oxygen requirement for Shigella and Salmonella?
Microaerophilic
Facultative anaerobic
Aerobic
Anaerobic
130
Which medication classes are typically avoided during pregnancy or childhood due to toxicity?
Fluoroquinolones, tetracyclines, sulfonamides
Azoles, macrolides
Aminoglycosides, cephalosporins
Macrolides, beta-lactams
131
In disk diffusion testing, what indicates that a strain is resistant to a drug?
Faint purple color
Red precipitate
Clear zone around disk
Growth up to the margin of the disk
132
What organisms are penicillinase-resistant penicillins designed to target?
MRSA and VRE
All strep and gram-negatives
MSSA and MSSE
Enterococcus spp.
133
What PK/PD parameter reflects both concentration and time-dependent activity?
Volume of distribution
T>MIC
MIC90
AUC:MIC
134
What side effect is associated specifically with procaine PCN formulations?
Thrombocytopenia
Severe diarrhea
Hoigne’s syndrome
Anaphylaxis
135
What tool helps select empiric therapy based on local resistance patterns?
Antimicrobial gradient
Culture result
Antibody panel
Antibiogram
136
What is the MIC interpretation for penicillin when MIC is ≥0.5?
S
SD
I
R
137
What organisms are common gram-negative rods in the lower respiratory tract?
E. coli and Salmonella spp.
H. influenzae and Klebsiella pneumoniae
Enterobacter and Moraxella spp.
Campylobacter and Haemophilus spp.
138
Which PK/PD parameter reflects the area under the concentration-time curve?
MIC
Cmax
PAE
AUC
139
What complication can occur in slow acetylators taking isoniazid?
Liver failure
Rash
Hemolysis
Peripheral neuropathy
140
What is the goal Cmax/MIC target for aminoglycosides and similar agents?
≥ 5
≥ 1.5
≥ 2
≥ 10
141
What does MIC stand for?
Mean inhibitory clearance
Microbial inhibition coefficient
Minimum inhibitory concentration
Maximum intracellular concentration
142
What gram-positive anaerobic cocci is found in the oral cavity?
Moraxella catarrhalis
Peptostreptococcus spp.
Streptococcus pneumoniae
Enterococcus faecalis
143
Which of these is bacteriostatic and used to inhibit protein synthesis?
Nitrofurantoin
Macrolides
Fluoroquinolones
Metronidazole
144
Which PK/PD index is associated with β-lactams, lincosamides, and monobactams?
Cmax/MIC
AUC:MIC
fT>MIC
PAE
145
What gram-positive rod is associated with skin and bone infections (excluding C. difficile)?
Actinomyces spp.
Bacillus cereus
Listeria monocytogenes
Clostridium spp.
146
What emerging method weighs individual organisms over time to determine MICs even faster than MCA?
Morphokinetic cellular analysis
Microfluidics screening
Resonant mass measurement
Whole genome sequencing
147
What is the interpretation of piperacillin/tazobactam with MIC ≤4.0 in the E. coli chart?
NI
I
SD
SS
148
Which two gram-positive cocci infect the upper respiratory tract?
S. pneumoniae and S. pyogenes
Enterococcus and Peptostreptococcus
S. aureus and S. agalactiae
Staphylococcus and Enterococcus
149
Which gram-positive cocci are covered by natural penicillins?
Streptococcus spp.
Staphylococcus aureus
Listeria monocytogenes
Enterobacter spp.
150
Which gram-negative cocci is associated with bone and joint infections?
Moraxella catarrhalis
Neisseria gonorrhoeae
Klebsiella pneumoniae
Haemophilus influenzae
151
Which yeast is known to have a capsule and can cause meningitis?
Rhizopus spp.
Aspergillus fumigatus
Cryptococcus neoformans
Candida albicans
152
What is it called when two drugs combined have a similar effect to each one alone?
Additivity
Antagonism
Synergy
Indifference
153
What kind of allergic reaction should be avoided with antibiotic use?
Rash only
Anaphylaxis or laryngospasm
GI upset
Photosensitivity
154
What type of bacteria do penicillinase-resistant penicillins not cover at all?
Gram-positive cocci
Gram-negative bacteria
Anaerobes
Spirochetes
155
Which class of antibiotics has minimal or no PAE except for staphylococci or P. aeruginosa?
Oxazolidinones
Tetracyclines
β-lactams
Macrolides
156
What test result combination is most typical of Pseudomonas aeruginosa?
Lactose negative, oxidase negative
Lactose positive, oxidase negative
Lactose negative, oxidase positive
Lactose positive, oxidase positive
157
Which formulation lasts up to 30 days and is used for rheumatic fever prophylaxis?
PCN G procaine
PCN G benzathine
PCN G IV aqueous
PCN VK
158
What does a “resistant” interpretation imply?
Organism is not inhibited by standard doses
Eradication requires narrow spectrum agent
Increased clearance of drug
Susceptibility increases at low dose
159
What are typical infections treated with oxacillin or nafcillin?
MSSA skin/tissue infections, endocarditis
VRE bloodstream infection
Gonorrhea
MRSA pneumonia
160
Which streptococcal conditions are commonly treated with natural penicillin?
UTI and cellulitis
Pharyngitis and endocarditis
Pharyngitis and pyelonephritis
Meningitis and otitis
161
Which CNS pathogen is a gram-positive rod?
Clostridium perfringens
Bacillus anthracis
Listeria monocytogenes
Actinomyces spp.
162
What is the new genus name for Candida glabrata?
Coccidioides glabrata
Histoplasma glabrata
Cryptococcus glabrata
Nakaseomyces glabrata
163
What symptoms are seen in Hoigne’s syndrome?
Seizures and hives
Psychosis, fear, auditory disturbances
Rash and vomiting
Liver failure and jaundice
164
Do penicillinase-resistant penicillins cover MRSA?
No
Yes
Only if combined with vancomycin
Only in high doses
165
Which of the following is NOT a true allergy?
Laryngospasm
GI disturbance (N/V/D)
Hives
Anaphylaxis
166
Which gram-negative rods are associated with bone and joint infections?
Bacteroides fragilis, Pseudomonas spp.
Salmonella spp.
Campylobacter spp.
Stenotrophomonas maltophilia
167
Are penicillinase-resistant penicillins effective against Enterococcus spp.?
Only IV
Sometimes
No
Yes
168
Which antibiotic classes show time-dependent killing (fT>MIC)?
Sulfonamides and glycopeptides
Macrolides and tetracyclines
Aminoglycosides and fluoroquinolones
β-lactams, lincosamides, monobactams
169
What PD parameter reflects the time free drug exceeds the MIC?
Cmax/MIC
Cmin
fT>MIC
AUC₀–₂₄
170
What is the classification of clindamycin based on its antibacterial activity?
Beta-lactam
Bactericidal
Antiseptic
Bacteriostatic
171
Which of the following is a gram-negative cocci?
Veillonella spp.
Haemophilus influenzae
Bacteroides fragilis
Neisseria gonorrhoeae
172
What enzyme deficiency increases the risk of hemolysis with sulfonamides or nitrofurantoin?
CYP2D6
Acetyl-CoA synthetase
Lactase
Glucose-6-phosphate dehydrogenase (G6PD)
173
Why is recent antimicrobial use important in selecting empiric therapy?
Improves response to same drug class
Encourages development of immunity
Enhances gut flora
Likely resistance to previously used agents
174
Which bacteria show variable lactose fermentation and oxidase positivity depending on species?
Klebsiella spp.
Providencia spp.
Serratia marcescens
HACEK organisms
175
What is the mechanism of bacteriostatic antibiotics?
Disrupt membranes
Kill bacteria directly
Inhibit DNA synthesis
Inhibit replication without killing
176
Which anaerobic bacteria are susceptible to natural penicillins?
Enterococcus spp.
Lactobacillus spp.
Clostridium spp. (not C. diff), Peptostreptococcus spp.
Bacteroides spp.
177
Which MIC method uses a plastic strip with an antibiotic concentration gradient on an agar plate?
Epsilometer test
Macrobroth dilution
Microbroth dilution
MCA
178
Which atypical bacteria is known for causing Legionnaires’ disease?
Legionella pneumophila
Chlamydophila pneumoniae
Chlamydia trachomatis
Mycoplasma pneumoniae
179
Which two antibiotics are interpreted as resistant (RRR) for E. coli in the chart?
Meropenem and ciprofloxacin
Nitrofurantoin and amikacin
Cefepime and aztreonam
Ampicillin and ceftriaxone
180
What yeast is often isolated in urinary tract infections?
Cryptococcus neoformans
Coccidioides immitis
Rhizopus spp.
Candida spp.
181
What factor includes evaluating safety concerns, contraindications, and adverse effects?
MIC interpretation
Drug-drug interactions
Antimicrobial susceptibility
Adverse effects and contraindications
182
What does PAE allow in terms of dosing strategy?
Increased frequency
Less frequent administration
Higher daily dose
Loading doses only
183
In the synergy graph, which line shows the most significant reduction in bacterial count?
Drug A alone
A + B combination
Drug B alone
No drug
184
Which formulation of penicillin is acid stable and given orally?
PCN G benzathine
PCN G procaine
PCN VK
PCN G
185
What term describes whether a drug kills or inhibits bacterial growth?
Drug cost
Spectrum of activity
Pharmacokinetics
Mechanism of action
186
Which organism is a non-lactose fermenter, oxidase negative, and an Enterobacterales member?
Proteus mirabilis
Stenotrophomonas maltophilia
Providencia stuartii
Pseudomonas aeruginosa
187
What does multidrug-resistant (MDR) risk assessment evaluate?
Need for anaerobic coverage
Likelihood of infection with resistant organisms
Potential for GI toxicity
Necessity of intravenous therapy
188
What must be considered when treating immunocompromised patients with hepatic or renal dysfunction?
No need for dose change
Drug accumulation unless adjusted
Enhanced clearance
Reduced half-life
189
What atypical bacteria lacks a cell wall and is resistant to beta-lactams?
Legionella pneumophila
Borrelia burgdorferi
Chlamydia trachomatis
Mycoplasma pneumoniae
190
Which method can detect non-genetic resistance mechanisms not screened by molecular tests?
PCR
MCA
Disk diffusion
Microbroth dilution
191
What is the term for starting antibiotics before the organism is identified?
Prophylaxis
De-escalation
Directed therapy
Empiric therapy
192
Is Neisseria meningitidis susceptible to natural penicillins?
No
Yes
Only in elderly
Only in high doses
193
Which of the following is NOT part of the Enterobacterales order?
Salmonella spp.
Klebsiella pneumoniae
Enterobacter cloacae
Pseudomonas aeruginosa
194
Which of the following antibiotic classes is bactericidal?
Tetracyclines
Sulfonamides
Cephalosporins
Chloramphenicol
195
What does an “intermediate” interpretation mean in susceptibility testing?
Eradication possible with high doses
MIC exceeds resistance cutoff
Agent should be avoided completely
Drug is ineffective
196
What is the purpose of the minimum bactericidal concentration (MBC)?
Kills 99.9% of the inoculum
Identifies allergic risk
Prevents resistance
Predicts side effects
197
What does T>concentration indicate?
Dosing frequency
Maximum concentration
Absorption rate
Time above threshold concentration
198
What type of agents are associated with AUC:MIC-based killing?
β-lactams and cephalosporins
Tetracyclines, lincosamides
Glycopeptides, oxazolidinones, fluoroquinolones
Macrolides, sulfonamides, aminoglycosides
199
What is the first step in evaluating organism factors?
Choose empiric therapy
Determine route of drug administration
Start broad-spectrum therapy
Identify the organism
200
Which of the following bacteria is oxidase positive and not part of Enterobacterales?
Citrobacter freundii
Klebsiella pneumoniae
Haemophilus influenzae
Morganella spp.

ID Packet Pages 11-20 Flashcards | StudBud