Antibiotics Flashcards
1
Q
What is empiric therapy
A
treatment prior to the identity of the organism
2
Q
When is empiric therapy indicated
A
In critically ill patients
3
Q
What type of treatment is given for empiric therapy
A
Broad spectrum
4
Q
What is antibiotic sensitivity consideration based on
A
Pattern of antibiotic sensitivity
Lab testing
5
Q
What is MIC
A
Lowest concentration of a drug that inhibits bacterial growth (minimal inhibitory concentration)
6
Q
What is MBC
A
Minimal bactericidal concentration
Lowest concentration of a drug that kills bacteria
7
Q
How do bacteriostatic antibiotics work
A
They inhibit bacterial replication but does not kill bacteria
Host defenses required
8
Q
What are some miscellaneous considerations to include when choosing an antibiotic
A
Route of administration
Tissue distribution
Route of metabolism/ elimination
Side effects/ toxicity
9
Q
What are the host specific considerations to have while choosing an antibiotic
A
Immune status
Anatomy
allergies
Bioavailability
Other drug interactions
age
pregnancy
renal function
10
Q
Why do you have to consider immune status before giving an antibiotic
A
Are they neutropenic
Do they have cell mediated defects
11
Q
What type of antibiotic would you give someone with a compromised immune system
A
bactericidal
12
Q
Why do you consider the anatomy before giving an antibiotic
A
Do they have an abcess, necrotic tissue, foreign material
Need to match the drug bioavailability to the site of infection
13
Q
What type of drug would you give for an immune protected area
A
Bactericidal
14
Q
What are some immune protected areas
A
CNS
Eye
Bacterial endocarditis
15
Q
Why is renal function important to consider before administering an antibiotic
A
Some drugs need to be dose adjusted because the kidney filters them
16
Q
Why is age important to consider before prescribing antibiotics
A
You should avoid chloramphenicol and sulfonamides in neonates
avoid tetracyclines in small children
17
Q
What type of antibiotic would you avoid prescribing during pregnancy
A
Aminoglycosides
18
Q
Which antibiotics are poorly absorbed in the GI tract and thus require IV admin instead of oral
A
Vancomycin and aminoglycosides
19
Q
What is synergy
A
When the combined effect of two antibiotics is greater than if they were given alone
20
Q
What is antagonism
A
When the combined effect of two antibiotics is worse than if given alone
21
Q
What is indifference
A
When the effect of 2 antibiotics equals that of their independent activity
22
Q
B-lactam combined with aminoglycosides against gram negative bacteria is an example of what type of interaction
A
Synergistic
23
Q
Penicillin (Bactericidal against susceptible forms of strep pneumoniae) combined with tetracycline (Bactericidal) would give what type of effect
A
Antagonistic
24
Q
What are some examples for antibiotic prophylaxis
A
prior to surgery
Pre dental extractions
Prevention of TB / meningitis
PJP in HIV infected patients
Recurrent UTI
25
Which antibiotics require dose adjustment in renal insufficiency
Penicillin
Amoxicillin
Piperacillin/ Tazobactam (Zosyn)
Cephalexin
Cefuroxime
Ciprofloxacin
Levofloxacine
Trimethoprim
Clarithromycin
26
Where are the common mechanism of action sites
Cell wall synthesis
Folic acid metabolism
Periplasmic space
Cell membrane
Protein synthesis
DNA gyrase
DNA directed RNA polymerase
27
What are the different types of protein synthesis in which antibiotics can have an effect
tRNA
30s inhibitors
50s inhibitors
28
What types of drugs are cell wall synthesis inhibitors
Penicillins
Monobactam
carbapenems
Combo agents
Cephalosporins
Glycopeptides
29
What is the mechanism of action for B-lactam antibiotics
Interfere with cell wall synthesis by binding to penicillin binding proteins.
This compromises the cell wall integrity = cell lysis
Enhances cell breakdown by activating autolytic enzymes
30
What are penicillin binding proteins
Transpeptidase enzymes that catalyze cross-linking of peptidoglycans
31
What is penicillin made up of
Thiazolidine
B-lactam ring
Side chain
32
What does the B lactate ring do
Essential for antibacterial activity
33
What does the side chain in penicillin do
Determines the antibacterial spectrum and pharmacologic properties of a particular penicillin
34
What are the classifications of penicillin
Natural
Aminopenicillin
Semi-synthetic
Ureidopenicillin
Beta lactamase inhibitor
35
What type of penicillin is considered natural
Penicillin G
Penicillin V
36
Which forms of penicillin are penicillinase sensitive
Natural
Aminopenicillin
37
What forms of penicillin make up the aminopenicillins
Ampicillin
Amoxicillin
38
What makes up the semi-synthetic penicillin
Nafcillin
oxacillin
Dicloxacillin
39
What types of penicillin are penicillinase resistant
Semi synthetic
40
What makes up ureidopenicillinl
piperacillin
Ticarcillin
41
How is piperacillin used
Never alone, always needs a b-lactam inhibitor
42
what type of penicillin treat gram positive cocci
Penicillin G, V
43
What pathogens are considered gram positive cocci
Strep pneumoniae
Group A strep (S. pyogenes)
Group B strep (S. agalactiae)
Group C,G strep
Viridans strep
44
What does Strep pneumoniae cause
Sinusitis
otitis media
Pneumonia
meningitis
45
What does group A strep cause
Bacterial pharyngitis
Cellulitis
toxic shock
Necrotizing fasciitis
46
What does group C,G strep cause
Cellulitis
Skin/soft tissue infections
47
What does group B strep cause
Meningitis in newborns
Bacteremia in elderly / diabetics
48
What pathogen does penicillin G,V not cover
Staph
49
What is penicillin V typically used for
Generally for group A strep (Strep throat)
Generally in kids or anyone with a doxycycline allergy
Syphillis
50
What type of gram negative cocci does natural penicillin treat
Neisseria meningitidis (Meningitis and bacteremia)
51
Why is natural penicillin not useful to treat N. Gonorrhoeae
Because of the widespread presence of penicillinase
52
What are the pharmokinetics for Penicillin V and G
Penicillin V = oral
Penicillin G = IV/IM
53
Why is penicillin not a good agent against bactericides fragilis and other bactericides spp?
Because of the presence of beta-lactamase
54
What is Natural penicillin's spectrum of activity for spirochetes
Works against
treponema pallidum (Syphilis)
Borrelia burgdorferi (Not typically used to treat Lyme though)
55
Why does penicillin G require frequent dosing when prescribed
Because of its 1/2hour half life
56
Which natural penicillin has better oral bioavailability
Penicillin V
57
If a patient requires an IM penicillin G administration, what is important to remember
That it cannot be given alone when given via IV
58
What is the most common side effect from Penicillin
Rash
59
What are the side effects of penicillin
Rash
Seizures
Anaphylaxis
60
When are patients at a high risk for seizures with penicillin
When a patient has a seizure disorder OR when a high dose of Pen G is given to someone with renal insufficiency
61
What is a contraindication for natural penicillin
Hypersensitivity to B-lactams antibiotics
Use with caution in patients with asthma or with a hx of multiple allergens
62
Which organism is penicillin resistant and why
S.aureus
Contains a penicillinase which hydrolyzes the beta lactase ring
63
If a patient has a suspected S. aureus infection- which antibiotic should NOT be used
Natural penicillin and Aminopenicillin
64
What is methicillin
The first penicillin developed to resist hydrolysis by staph beta-lactamase
65
What is methicillin used for
Treatment of infections caused by penicillinase-producing staph
66
Which type of penicillin is more useful against strep A, Strep B, and strep pneumonia
Penicillin G
67
What organism is semi-synthetic penicillin not useful against
Gram - activity
68
What is the IV/IM form of semi-synthetic penicillin
Nafcillin and oxacillin
69
What is the PO form of semi-synthetic penicillin
Dicloxacillin
70
Which semi-synthetic penicillin do not require renal or hepatic dosing adjustments
Dicloxacillin
Oxacillin
71
If a patient comes in with an MSSA infection... what would be the best type of penicillin to treat it with
Oxacillin or nafcillin
72
If a patient comes in with elevated creatinine, fever, and peripheral eosinophilia, what is their likely diagnosis
Allergic interstitial nephritis
73
What causes neutropenia with oxacillin/nafcillin dosing and when is it seen
Occurs 3 wks after a high dose therapy and is treated by decreasing the dose
74
Which antibiotic is 2x more active against enterococci than penicillin
Ampicillin or amoxicillin
75
If a patient comes in with listeria monocytogenes, what would be the antibiotic used to treat
Ampicillin or amoxicillin
76
What is the cause of meningitis in immunosuppressed patients, newborns, and individuals over 50
Listeria monocytogenes (Aminopenicillin better to treat than natural penicillin)
77
What is ampicillin/amoxicillin spectrum of activity against gram positive cocci
Active agent against penicillin-susceptible s. aureus
Not useful for most S.aureus though because of the beta-lactamase ring
78
What kind of gram - bacteria do ampicillin/amoxicillin treat
H. Influenzae
E. coli
*~40% resistant due to beta-lactamase
79
What are the common side effects of ampicillin and amoxicillin
Rash (4-8%)
Diarrhea (2-5%)
- worse is ampicillin
80
If a patient is given amoxicillin when they have infectious mononucleosis, what is the likely reaction going to be
Erythematous rash
81
What happens to the spectrum of activity if you combine B-lactamase inhibitors
Increase
82
When is IV ampicillin-sulbactam used (unasyn)
MSSA (gram+)
H. influenza , E.coli, K. Pneumonia (Gram -)
Bacteroides Fragilis (Anaerobe)
83
When is PO amoxicillin-clavulanate used (Augmentin)
MSSA (gram+)
H. influenza , E.coli, K. Pneumonia (Gram -)
Bacteroides Fragilis (Anaerobe)
84
What do beta-lactamase inhibitors treat better than ampicillin/amoxicillin
Better gram negative activity
85
What are the narrow-spectrum b-lactamase susceptible agents
Sreptococci
enterococci
Anaerobes
86
What are the very narrow spectrum B-lactamase resistant agents
S.Aureus, s epidermidis, streptococci
87
What type of drug is cephalosporin
Bactericidal
88
How is cephalosporin different from penicillin
Resistant to hydrolysis by beta-lactamase
R1&R2 side chain substitutions alter antibacterial spectrum and pharmokinetics
89
How are cephalosporins classified
By generation in order of their development
90
How does cephalosporin change with each generation
Increase gram negative activity with loss of gram positive activity
91
Why does cephalosporin have greater resistance to b-lactamases than penicillin
Because cephalosporin has a 6-membered ring (Larger than penicillin)
92
What are some adverse reactions for cephalosporin
Hypersensitivity
Superinfections
93
What is the mechanism of action for cephalosporin
Inhibits bacterial cell wall synthesis
94
How is ceftriaxone administered
IV
95
Which forms of Cephalosporin is administered via IV therapy
Ceftriaxone
Cefepime
Ceftaroline
Ceftazidime
cafazolin
96
If a person came in and was diagnosed with MRSA, what could you give as a treatment
Vancomycin
97
How is aztreonam administered
IV/IM
98
What class of drug is aztreonam
Monobactam
Broad gram- activity including pseudomonas aeruginosa
99
What is the mechanism of action for aztreonam
Prevents peptidoglycan cross-linking by binding to PBP3
100
What can aztreonam be given as an alternative to
Aminoglycosides and 3rd generation cephalosporin
101
What type of pathogen does aztreonam NOT work against
gram + or anaerobic activity
102
What type of antibiotic is vancomycin
Non b-lactam
glycopeptide
bactericidal
103
What is the mechanism of action for vancomycin
Inhibits cell wall synthesis by binding the D-Ala-D-Ala terminal of the forming glycopeptide which prevents cross linking
104
When is vancomycin used
When there is a drug resistant gram + infection (MRSA and C.Diff)
105
What type of infection is vancomycin not helpful against
Gram negative activity
106
What are the side effects of vancomycin
Infusion related flushing (Red man syndrome)
Ototoxicity / nephrotoxicity
107
What is red man syndrome
Infusion related flushing
108
When are you more likely to get ototoxicity or nephrotoxicity with vancomycin
At higher doses or in the presence of other toxic drugs
109
Which type of infection of vancomycin resistant
VRE and VRSA
110
What is the drug of choice against MRSA
Vancomycin
111
What type of antibiotic is daptomycin
Lipopeptide
Bactericidal
112
How is daptomycin administered
IV only
113
Is daptomycin a broad spectrum or narrow spectrum antibiotic
Narrow
114
When is daptomycin a useful treatment
With resistant gram positive cocci
-VRE
-MRSA
115
What is a primary toxicity associated with daptomycin
Myositis (Myopathy, muscle pain)
116
What are carbapenems
Structure of the b-lactam ring that is highly resistant to B-lactamases
117
What is one of the broadest spectrum antibacterial agents on the market
carbapenems
118
What are carbapenems useful against
Gram positive cocci (MSSA, MSSE, S. Pneumonia)
Gram - rod and resistan gram- rods
Anaerobes
119
An increased expression of AmpC gene is regulated by presence of substrates like what?
3rd generation cephalosporin and other genes
120
What are the SPACE organisms
Serratia marcescens
Proteus spp
Acinetobacter baumannii
Citrobacter Freundii
Enterobacter spp
121
What does ESBL stand for
Extended spectrum b-lactamases
122
What are ESBL organisms
TEM-1
Allow for drug resistance against Beta lactams
123
Which bacteria are ESBL found on
E.coli and klebsiella
124
What drug is typically needed against an ESBL
>3rd generation cephalosporin
125
What are 3 types of carbapenems
Imipenem
Meropenem
Ertapenem
126
Which carbapenem is most toxic
Imipenem
127
What is imipenem inactivated by and what are common side effects
Renal dehydropeptidase
Encephalopathy and seizures
128
What does imipenem need to be given with to inhibit DHP
cilastatin
129
What is the difference between imipenem and meropenem
Meropenem is not inactivated by DHP and is less likely to cause seizures
130
What kind of gram + organisms that can be treated by carbapenems
MSSA
MSSE
131
What is the spectrum of activity of carbapenems against gram negative organisms
Enterobacteriaceae (Excellent activity against)
Good ESBL
Pseudomonas
132
What type of drug is fosfomycin
Bactericidal
133
What is the mechanism of action of fosfomycin
Inhibit the first step of bacterial cell wall synthesis by inhibiting pyruvyl transferase
134
When is fosfomycin typically used
Treatment of UTIs
particularly those caused by E. coli and enterococcus faecalis
135
What are the side effect of fosfomycin
Diarrhea
vaginitis
136
What is the mechanism of action for Daptomycin
It alters the curvature of the cell membrane which leads to holes and leaks, completely disrupting the cell membrane
137
How is Fosfomycin administered
One time oral dose
