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Cmbm 2 Gopi > Antibiotics > Flashcards

Antibiotics Flashcards

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0
Q

resistant worries for Vancomycin

A

resistant gene on plasmid(means very mobile gene) being picked up by MRSA

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1
Q

Vancomycin

A

MRSA
penicilin resistant S. pneumo
susceptible enterococcal infections

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2
Q

Drug for vancomycin resistant Enterococci

A

Dancomycin

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3
Q

Target of beta lactam antibiotics

A

Peptidoglycan synthesis

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4
Q

Aerobic gram +

A

staph
strep
enterococci
listeria

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5
Q

anaerobes

A 
clostridium 
actinomyces 
peptostreptococcus 
propionibacterium 
bacteroides 
fusobacterium 
prevotella
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6
Q

aerobic (facultative) gram negative

A

enterobacteriaceae
neisseria
pseudomonas
haemophilus

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7
Q

Atypical/intracellular bacteria

A 
mycoplasma 
chlamydia 
legionella 
mycobacterium 
rickettsia 
spirochetes
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8
Q

Examples of Aminoglycosides

A

streptomycin
gentamicin
amikacin

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9
Q

toxicities of aminoglycosides

A

nephrotoxicity - see elevated creatinine

ototoxicity

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10
Q

Macrolides and Ketolides

A 
Broad spectrum but not deep 
Erythomycin 
Clarithromycin
Azithromycin (known as z pack) 
Telithromycin - ketolide
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11
Q

mechanism of Macrolides

A

bind 23S rRNA of the 50s ribosome

prevents protein elongation

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12
Q

Telithromycin

A

binds at 2 sites

ketolides

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13
Q

Erythromycin

A

can cause GI upset - makes pt nauseous

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14
Q

Azithromycin

A

longer half life

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15
Q

clinical uses for Macrolides

A

empiric therapy for community aquired pneumonia (CAP)

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16
Q

DOC for legionella, mycoplamsa, and chlamydia

A

Macrolides

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17
Q

Most aerobic gram neg rods are resistant to

A

Macrolides

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18
Q

Resistance to Macrolides

A

Efflux pump

Enzyme mediated methylation of binding site on 23S ribosome

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19
Q

Examples of Lincosamide

A

Clindamycin

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20
Q

Clidamycin active against

A

generally anaerobic drug
aerobic gram + including MRSA and s. pneumo
gram + and - anaerobes
some protozoans

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21
Q

mechanism of Tetracyclines

A

bind reversibly to 30s subunit

blocks binding of tRNA

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22
Q

What is clindamycin not useful for?

A

aerobic gram negatives

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23
Q

Tetracycline

A

broad range many aerobic gram pos and neg
anaerobes
Atypicals - especially useful
some protozoa

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24
Adverse reactions to Tetracyclines
Not given to childern under 8 Not used in pregnancy Cause photosensitization - bad sunburn
25
Fluoroquniolones
``` Ciprofloxacin - below the waist Gatifloxacin levofloxacin oflaxacin moxifloxacin ```
26
DNA gyrase inhibitor
Fluoroquinolones
27
clinical uses of fluoroquinolones
broad spectrum aerobic, gram neg bacteria active against strains of staph and strept and many atypical
28
toxicities of Fluoroquinolones
may damage growing cartilage - so no childern under 18 or pregnant women Black box warning of tendon rupture
29
Anti folate drugs
TMP/SMX sulfonamides trimethoprim
30
anerobic drug
metronidazole | clindamycin
31
TMP/SMX mechanism and activity
``` broad spectrum interferes with folate synthesis by bacteria which is needed for nucleic acid synthesis aerobic gm pos (CA-MRSA) some aerobic gm neg non bacterial organisms ```
32
Clinical uses of TMP/SMX
UTI RTI prostate and vaginal infections
33
Toxicities of TMP/SMX
skin rash | GI upset
34
bacteriocidal antibiotics
antibiotics that target cell wall causing lysis of bacteria beta lactams vancomycin daptomycin - cell membrane
35
Antibiotics that block protein synthesis
``` aminoglycosides 30s macrolides 50s tetracyclines 30s clindamycin 50s chloramphenical 50s linezolid 50s ```
36
Bacterostatic
antibiotics that inhibit growth and/or replication
37
Antibiotics that inhibit RNA synthesis
Rifamycin | Rifabutin
38
Antibiotics that target DNA or DNA synthesis
Quniolones metronidazole clofazimine
39
Antimetabolite antibiotics
Trimethoprimsuflamethoxazole (TMP/SMX) dapsone para-aminosalicylic acid
40
Empirical
treatment before receiving the test/cultures back
41
Beta lactams
``` Effective for certain Gr+ or Gr- Penicillins cephalosporins carbapenems monobactams ```
42
Antibiotics for Gram + cocci
Vancomycin | Daptomycin
43
TB drugs
Isonizad Ethambutol Pyrazinamide
44
Peptidoglycan synthesis and structure
Composed of alternating NAG and NAM units linked by transpeptidases (PBP) via D-Ala D-Ala units
45
Cyloserine
inhibits reactions involved in incorporation of alanine into cell wall percusor
46
Glycopeptides
bind to terminal D-ala-D-ala residues prevents incorporation of subunit into growing peptidoglycan
47
Bacitracin
prevents dephosphorylation of phospholipid carrier which prevents regeneration of carrier necessary for synthesis to continue in building peptidoglycan walls
48
Beta lactams
bind to end inhibit enzymes which catalyze this link
49
Mechanism of action of beta lactam antibiotics
transpeptidases catalyse crosslinking of peptidoglycan residues beta lactam antibiotics bind transpep. and block this reaction resulting in weak cell walls and bacterial lysis if bacteria are actively growing Bacteriocidal
50
Types of Penicillins
natural anti-staph penicillins aminopenicillins extended spectrum
51
what is unique about the structure of Penicillin
B lactam ring | Thiazolidine ring - essential for activity
52
Natural penicillins
``` 5 is oral G is IV or IM limited spectrum Most strept - GAS, GBS, viridians group NOT s. pneum Most gram + anaerobes N. meningitidis Treponema pallidum ```
53
Poor activity against aerobic and anaerobic gram neg rods and not active for intracellular bacteria
natural penicillin
54
Anti Staph Penicillin
Many staph make beta lactamases this antibiotic have large side groups making resistant to lactamases Naficillin and Oxacillin (IV) Dicloxacillin (oral)
55
Anti Staph penicillin activity
MSSA MSSE - methicillin resistant staph epidermidis Not active against MRSA MRSE
56
How is methicillin resistance confered?
due to altered PBP
57
Aminopenicillin
Ampicillin Amoxicillin amino group is R group - allows penetration through porins of some gram neg (esp. enteric rods) better absorption through GI than natural penicillins
58
Aminopenicillins activity against
``` limited spectrum similiar to natural PLUS E.coli Shigella Salmonella enterica AND borrelia burgdorferi ```
59
Extended spectrum penicillins
Piperacillin Ticarcillin Carbenicillin better able to penetrate gram neg porins than aminopencillins
60
spectrum of extended spectrum penicillins
same as natural PLUS more enterobacteriaceae some strains of pneumonia aeruginosa AKA anti pseudomonal penicillins
61
What is used in combination with aminopenicillins and extended spectrum penicillins?
B lactamase inhibitors
62
Some bacteria that contain beta lactamases
``` Staph. Aureus H. Inf N. gonorrhoeae Many enterobacteriaceae certain anaerobes ```
63
B lactamase inhibitors
can contain b lactam ring to act as decoy or inhibit lactamases following binding Clavulanic acid sulbactam tazobactam
64
Extended spectrum penicillin (ESP) and b lactamase inhibitors
Big guns some of most potent available Piperacillin/Tazobactam (Zosyn) Ticarcillin/clavulanate (Timentin) ``` gives ESP spectrum PLUS S. Aureus S. pneumo Most enterobacteriacae Most pseudomonas ```
65
Major toxicity of penicillins
Hypersensitivity rxns acts as hapten but immunogenic when binds RBC Type 1 response - skin rash, Anaphylaxis Type 2 response - Drug induced hemolytic anemia
66
What is more resistant to Beta lactamases than natural penicillins?
Cephalosporins and cephamycins
67
On cephalosporins R1 and R2 side chains affect
R1 - antibiotic activity | R2 - affect change in PK properties
68
First generation cephalosporins
cefazolin | cephalexin
69
Second generation
Cefotetan cefoxitin cefuroxime
70
Third generation cephalosporin
ceftriaxone
71
fourth generation cephalosporin
cefepime
72
Cephalosporins and cephamycins
beta lactam antiobiotics more active against gram neg than natural penicillins More stable too against many beta lactamases in general: increasing generation - aerobic gm + decreases and aerobic gm - increase generally not useful against anaerobes or intracellular organisms
73
Clinical First generation cephalsporin
spect: GAS, viridians, s. pneumo, PLUS some E. coli, klebsiella, proteus Minor skin and soft tissue infections (alt to anti staph pen) UTIs (E.coli)
74
Second generation cephalosporins
same spect as first generation PLUS H. Inf Neisseria species
75
Third generation cephalosporins
moderate against aerobic gram + bacteria - MSSA PLUS increased activity against aerobic gram - b/c modification of R side chains allow increased penetration through porins some can cross the BBB - cefotaxime and ceftriaxone activity against anaerobes - ceftizoxime activity against pseudomonas - ceftazidime
76
aerobic gram positive think ....
Staph | strept
77
N. gonorrhae
resistant to a lot of antibiotics | becoming more and more of a problem
78
N. meningitidis
not usually problem | can treat with penicillin
79
Fourth generation
cefepime Spectrum 3rd gen PLUS MSSA activity against pseudomonas - increased penetration thru porins and affinity to PBP increased against Enterobacteriaceae - increased resistance to beta lactamases
80
Fourth generation poor against
anaerobes
81
Carbapemems
``` Use for very serious infections - Big guns Imipenem, meropenem, ertapenem Among MOST broad spectrum among LAST LINE of defense against resistant bacteria improved penetration of porins enhanced binding to PBP increased resistance to beta lactamases USEFUL for pseudomonas ```
82
LAST LINE antibiotic
carbapemems | some Ecoli and klebsiella developed resistance
83
Carbapenems NOT active against
enterococcus MRSA C. Diff Burkholdreia cepacia
84
Hail Mary - last resort antibiotic
Imipenem used with cilastatin (combo called Primaxin) to inhibit renal dihydropeptidase
85
Monobactams
Aztreonam side groups give ability to penetrate porins and bind to gram neg PBP CANNOT bind gram + PBP
86
Excellent safety profile
Monobactams safe for pts with penicillin allergies and renal disease Useful for pseudomonas
87
Spectrum of Monobactams
Narrow spectrum Aerobic gram neg Moraxella, neisseria, enterobacteriaceae*, pseudomonas*, haemophilus, burkholderia * some strains developed resistance
88
Bacterial Mechanisms of resistance to Beta lactams
penetration - poor thus intracellular bacteria not affected Porins - beta lactams must be able to pass through pores - mutations of porins can alter acessibility Pumps - efflux pumps Penicillinases - beta lactamases Penicillin binding proteins - mutation prevents binding Peptidoglycan - lacking cell wall intrinsically gives resistance
89
Intrinsic resistance to beta lactams
intracellular growth lack of cell wall porin that excludes antibiotics
90
Acquired resistance to beta lactams
mutation genes from phage - transduction genes from another bacteria - transformation and conjugation altered penicillin binding proteins - methicillin resistant efflux pumps (pseudmonas have mutli drug resist pumps) decreased permeability of gram neg porins
91
Mechanism of resistance to Cephalosporins
production of beta lactamases
92
Vancomycin
Laser guided missile Huge, wont fit through porin spectrum very narrow Gram positive only
93
Mechanism of Vancomycin
cell wall inhibitor - binds to D-Ala-D-Ala
94
Resistance to Vancomycin
Enterococci change to D-Ala-D-lac | resistance gene on plasmid thus concern could transfer to MRSA
95
Clinical app of Vancomycin
reserve use for MRSA penicillin resistant S. pneumo susceptible enterococcal infection
96
Daptomycin
``` Laser guided missile - narrow spectrum cyclic lipopeptide antibiotic lipid portion inserts forming channel in membrane induces bacterial lysis active against aerobic gram + not useful for gram neg bacteria ```
97
for Vancomycin resistant enterococci
Daptomycin
98
Reserve for MRSA, penicillin resistant S. pneumonae, vancomycin resistant enterococci
Daptomycin
99
No Alcohol with this drug
Metronidazole
100
Metronidazole
acts as free radical causing strain breaks bacterial DNA | Active against gram neg anaerobes and most gram pos anaerobes including C. Diff
101
Latent TB treated with
Isoniazid
102
Penicillin sensitive S. Pneum
Penicillin G | Ampicillin
103
Penicillian resistant S. Pneumo
``` can overcome intermediate resistance by increasing dosage otherwise cefuroxime ceftriaxone vancomycin macolides or telithromycin ```
104
Staph. Aureus aerobic and gram + cocci causes what illnesses
``` skin and wound infections septicemia Endocarditis Pneumonia septic arthritis and osteomyelitis ```
105
All MSSA strains have what mechanism
Beta lactamase production
106
MRSA resistance confers resistance from
altered PBP
107
Antibiotics for MSSA
Anti staph penicillins - Nafcillin, oxacillin | Cephalosporins - 1-3rd generation - cefazolin, cefuroxime, ceftriaxone
108
Antibiotic for Staph Aureus (not MSSA or MRSA)
beta lactam plus beta lactamase inhibitor Ampicillin-sulbactam Piperacillin-tazobactam Ticarcillin-clavulanate
109
Antibiotics for MRSA (hospital acquired)
Vancomycin
110
Antibiotics MRSA (community acquired)
clindamycin
111
Antibiotics for MRSA
Linezolid Quinupristin-dalfopristin Daptomycin Tigecycline (like tetracycline) culture and sensitivity tests should guide therapy
112
MRSA isolates may be susceptible to other non beta lactam antibiotics including
clindamycin doxycycline minocycline
113
Pseudomonas Aeruginosa
causes serious infections in compromised hosts bacteremia pneumonia UTIs wound infection lungs of CF patients chronically infected
114
Always base therapy on culture and sensitivity results for this organism
P. Aeruginosa
115
Resistance mechanisms of P. Aeruginosa
multidrug efflux pump beta lactamase production altered porin proteins aminoglycoside-modifying enzymes
116
Combination therapy for Pseudomonas
ceftazidime and tobroamycin (beta lactam and aminoglycan) | Piperacillin and ciprofloxacin (extend spectrum and Fluoro)
117
Treatment for pseudomonas
Extended spectrum penicillins (piperacilin and ticarcilin) Cephalosporins (ceftazidime 3rd and cefepime 4th) Carbapenems Aztreonam Quinolones - some strains Aminoglycosides
118
enterobacteriaceae
aerobic (facultative) gram neg rods | many produce bet lactamases some with broad activity - extended spectrum beta lactamases
119
E coli can cause
``` diarrhea intrabdominal infections sepsis UTIs meningitis in infants ```
120
shigella
diarrhea | person to person transmission
121
salmonella
diarrhea | animal to person
122
klebsiella
pneumonia
123
Proteus
UTIs
124
Yersinia
diarrhea | plague
125
E coli, klebsiella and Proteus
ampicillin cefazolin TMP/SMX fluroquinolones
126
If enterobacteriaceae is resistant, use bigger guns
3rd gen - cephalosporins, aztreonam, piperacillin-tazobactam, ticarcillin-clavulanate, carbapenems can add aminoglycans for synergy
127
N. Gonorrhoeae DOC
problem organisms, lots of resistance Ceftriaxone (3rd gen) cefixime many resistance mechanisms -efflux pumps, beta lactamases, altered PBP, altered porins
128
N. meningitidis. Treat with?
penicillin if resistant, use ceftriaxone or cefotaxime (3rd)
129
Gram positive anerobes
clostridium actinomyces peptostreptococcus propionibacterium
130
Gram negative anerobes
bacteriodes fusobacterium prevotella
131
Antibiotics active against at least some Anaerobes
penicillin clindamycin metronidazole some second and third generation cephalosporins beta lactam/beta lactamase inhibitor combinations
132
C. Diff causes
antibiotic resistant associated colitis | causes diarrhea and pseudomembranous
133
C Diff treatment
metronidazole - given first | Vancomycin
134
Tetracyclines, Macrolides and quinolones are effective for
mycoplasma (intracellular) chlamydia (intracellular) Legionella (intracellular) Rickettsia (intracellular) - no macrolide
135
B. burgdorferi - treat with?
doxycycline BUT if kid under 18 use aminopenicillin
136
T pallidum treat with?
penicillin
137
what is the second line of drugs for M.tb
``` streptomycin para-aminosalicylic acid cycloserine ethionamide amikacin levofloxacin capreomycin ```
138
MDR-TB is resistant to ?
Isoniazid | Rifampcin
139
XDR-TB is resistant to?
Isoniazid Rif fluoroquinolone and one of three injectable second line drugs (capre, kana, amik)
140
What anti Tb drugs acts through inhibiting cell wall synthesis?
Isoniazid | Ethambutol
141
What Tb drug acts through disrupting the membrane?
Pyrazinamide
142
What drug for TB inhibits RNA synthesis?
Rifampin

Cmbm 2 Gopi (16 decks)

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