MT6314 ANTIMICROBIALS BETA LACTAMS Flashcards
1
Q
Drugs that inhibit the growth/replication, or kill microrganisms
A
Antimicrobials
2
Q
Antimicrobials include what kind of drugs based on their target molecule?
A
̶ Antibacterial
̶ Antifungal
̶ Antiviral
̶ Anti-protozoal
̶ Anti parasitic
3
Q
Antimicrobials are under that kind of drugs?
A
chemotherapeutic drugs
4
Q
2 kinds of bacteria?
A
Gram-positive
Gram-negative
5
Q
Bacterial cell wall synthesis inhibitors include?
A
Penicillins
Cephalosporins
Miscellaneous
6
Q
2 kinds of penicillins?
A
Narrow spectrum
Wider spectrum
7
Q
2 kinds of cephalosporins?
A
Narrow spectrum
Wider spectrum
8
Q
Kinds of miscellaneous bacterial synthesis inhibitors?
A
Carbapenems
Aztreonam
Vancomycin
9
Q
First to suggest that a Penicillium mold (now known as Penicillium chrysogenum) must secrete an antibacterial substance
A
Sir Alexander Fleming
10
Q
Sir Alexander Fleming suggested that _____ must secrete _________
A
Penicillium mold (Penicillium chrysogenum)
antibacterial substance
11
Q
First to concentrate the active substance involved, which he named penicillin, in 1928.
A
Sir Alexander Fleming
12
Q
Penicillins are derivates of?
A
6-aminopenicillamic acid
13
Q
Penicillins contain what structure?
A
beta lactam ring structure
14
Q
What determines the drug’s stability to enzymatic or acidic hydrolysis?
A
Nature of the R group
15
Q
The nature of the R group also affects?
A
Antibacterial spectrum
16
Q
The beta-lactam ring is the site of?
A
Hydrolysis by bacterial penicillinase or by acid
17
Q
Penicillin basic structure includes?
A
- Thiazolidine ring (A)
- β-lactam ring (B) that carries a secondary amino group (RNH–)
18
Q
R group penicillins include?
A
Penicillin G
Penicillin V
Oxacillin
Dicloxacillin
Nafcillin
Ampicillin
Amoxicillin
Piperacillin
19
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Ampicillin
A
1st gen cephalosporin
20
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Cefazolin
A
2nd gen cephalosporin
21
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Cefaclor
A
3rd gen cephalosporin
22
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Aztreonam
A
Monobactams
23
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Biapenem
A
Carbapenems
24
Q
WHAT KIND OF B-LACTAM ANTIBIOTICS: Amoxicillin
A
Penicillins
25
WHAT KIND OF B-LACTAM ANTIBIOTICS: Ertapenem
Carbapenems
26
WHAT KIND OF B-LACTAM ANTIBIOTICS: Doripenem
Carbapenems
27
WHAT KIND OF B-LACTAM ANTIBIOTICS: Imipenem
Carbapenems
28
WHAT KIND OF B-LACTAM ANTIBIOTICS: Panipenem
Carbapenems
29
WHAT KIND OF B-LACTAM ANTIBIOTICS: Tigemonam
Monobactam
30
WHAT KIND OF B-LACTAM ANTIBIOTICS: Carumonam
Monobactam
31
WHAT KIND OF B-LACTAM ANTIBIOTICS: Nocardicin A
Monobactam
32
Pharmacokinetics of antimicrobials vary in?
Vary in their oral availability
33
Penicillins are polar or non-polar?
Polar
34
T or F: Penicillins are metabolized extensively
F, not metabolized extensively
35
How is penicillin excreted and it is inhibited by?
̶ Excreted unchaned in urine
̶ Inhibited by Probenecid
36
When do antimicrobials cross the BBB?
when meninges are inflamed (MENINGITIS)
37
How should antimicrobials be given usually?
on an empty stomach; except Amoxicillin
38
MOA of antimicrobials?
*Bactericidal drugs
*Inhibit cell wall synthesis
1. Binds to PBP
2. Inhibits transpeptidation
3. Activation of autolytic enzymes
39
Antimicrobials inhibit what action of bacterial cell wall synthesis?
transpeptidation reaction
40
What is the final step of the synthesis of the peptidoglycan?
Cross linking of PEP side chains
41
The cross linking of PEP side chains is blocked by?
Penicillin
42
Antimicrobial resistance is brought about by?
Hydrolysis of the β -lactam ring by bacterial β -lactamases
Modification of PBP
Changes in membrane permeability
43
Clinical uses of penicillins?
*Narrow spectrum penicillinase susceptible agents
*Very Narrow spectrum penicillinase resistant agents – against Staphylococcus aureus
*Wider spectrum penicillinase susceptible drugs
44
limited spectrum; susceptible to β-lactamases
Penicillin G
45
Penicillin G is susceptible to?
β-lactamases
46
Penicillin G is used for?
streptotocci, meningococci, gram-positive bacilli, spirochetes
47
What is the first line drug for syphilis?
Benzathine Penicillin G
48
Benzathine Penicillin G is given how?
IM
49
Narrow spectrum penicillinase susceptible agents include what drugs?
Pen G
Pen V
50
Very Narrow spectrum penicillinase resistant agents – against Staphylococcus aureus, include what drugs?
Methicillin
Oxacillin
Cloxacillin (Dicloxacillin)
51
Wider spectrum penicillinase susceptible drugs include?
Ampicillin and Amoxicllin
Piperacillin and Ticarcillin
52
Wider spectrum than Pen G
Ampicillin and Amoxicllin
53
Ampicillin and Amoxicllin are enhanced when used with?
penicillinases (BLIC or beta-lactam-inhibitor combination)
54
Piperacillin and Ticarcillin have enhanced activity against?
gram-negative (Pseudomonas, Enterobacter, Klebsiella)
55
Piperacillin and Ticarcillin is usually combined with?
penicillinase inhibitors
56
Toxicity of antimicrobials include?
Allergy – urticaria, pruritus, fever, joint swelling, anemia, anaphylaxis
GI disturbances : nausea, diarrhea
57
Toxicity of Methicillin causes?
interstitial nephritis
58
Toxicity of Nafcillin causes?
Neutropenia
59
Toxicity of Ampicillin causes?
rash (non-allergic)
pseudomembranous colitis
60
Resemble β -lactam molecules, but have very weak antibacterial action
Beta-Lactamase inhibitors
61
Beta-Lactamase inhibitors resemble what?
β -lactam molecules
62
T or F: Beta-Lactamase inhibitors have strong antibacterial action
F, very weak
63
Beta-Lactamase inhibitors are combined with what to protect them from?
Combined with beta-lactam antibiotics to protect them from β-lactamases
64
Protection of the Beta-Lactamase inhibitors from β-lactamases subsequently protects them from?
inactivation
65
Beta-lactamase inhibitors are available only in?
fixed combinations with specific penicillins and cephalosporins
66
Cephalosporins are derivatives of?
7-aminocephalosporanic acid
67
T or F: Cephalosporins do not contain a B-lactam structure.
F, they contain one
68
Who isolated Cephalosporin C compound in from the fungus Acremonium?
Giuseppe Brotzu
69
Giuseppe Brotzu isolated ________compound in from the fungus________, previously known as _____________ in 1945.
Cephalosporin C
Acremonium
"Cephalosporium”
70
More stable to many bacterial β–lactamases, has broader spectrum of activity
Cephalosporins and Cephamycins
71
How many sites of attachment do Cephalosporins and Cephamycins have for what groups?
2 sites of attachment for various R1 and R2 groups
72
T or F: Cephalosporins and Cephamycins are more stable compared to other bacterial β–lactamases
T
73
R group at 7-position is R1 or R2?
R2
74
R group at 3-position is R1 or R2?
R1
75
R group at 7-position function?
alters antibacterial activity
76
R group at 3-position function?
modifies pharmacokinetic profile
77
Route of administration of cephalosporins?
Most are parenteral/ IV
78
Major elimination of cephalosporins are by?
renal extretion; some with side chains – hepatic metabolism
79
Which cephalosporins are excreted in the bile?
Cefoperazone and ceftriaxone
80
Do not cross BBB even in inflamed meninges
1st and 2nd generation cephalosporins
81
When cephalosporins bind to the PBP, what occurs?
inhibit cell wall synthesis, similar to penicillins
82
Cephalosporins are?
bactericidal
83
Structural differences render cephalosporins less suseceptible to ____________
penicillinases produced by staphylococci
84
Some organisms are resistant through production of?
other beta-lactamases vs cephalosporins
85
What bacteria is resistant to cephalosporins?
MRSA
86
Clinical Uses of 1st Generation drugs?
Cefazolin and cephalexin – against G+ cocci, E coli, K pneumoniae
87
Clinical Uses of 2nd Generation drugs?
̶ Less activity against G+, extended G- overage
̶ Anaerobic coverage : Cefotetan, Cefoxitin
̶ H influenzae, M catarrhalis: Cefamandole, cefuroxime, cefaclor
88
3rd generation drugs include?
Ceftazidime, cefoperazone, cefotaxime
89
3rd Generation drugs have what kin of clinical use?
̶ Increased activity for G-; penetrates BBB (except Cefoperazone and Cefixime)
90
Drug used against gonococcal urethritis?
Ceftriaxone (3rd gen)
91
Clinical Uses of 4th generation drugs?
̶ Cefepime – more resistant to beta lactamases; combines gram positive activity of 1st gen. with wider gram neg. spectrum of 3rd gen.
̶ Ceftaroline – active against MRSA
92
Toxicity of antimicrobials?
Allergy – from rashes to anaphylactic shock
Complete cross reactivity should be assumed
93
Percentage of cross reactivity between penicillin and cephalosporin is assumed to be?
5-10%
94
First generation cephalosporins are predominantly active against ______, with succeeding generations progressively more active against ______ strains (often with reduced ______ activity except ____ generation, which are extended spectrum agents)
Gr(+)’s
Gr(-)
Gr(+)
4th
95
Cephalosporins are inactive against?
Listeria
Atypicals
Methicillin-resistant staphylococcus aureus (MRSA)- except Ceftaroline
Enterococcus
96
Coverage of 1st generation cephalosporins?
Gr(+) cocci, E.coli, K pneumoniae, and Proteus mirabilis
97
Coverage of 2nd generation cephalosporins?
same as 1st gen but with extended Gr(-) activity- Klebsiella, H. influenzae, Bacteroides fragilis, Serratia
98
Coverage of 3rd generation cephalosporins?
Expanded Gram-negative coverage: Citrobacter, serratia, providencia, Pseudomonas (Ceftazidime)
99
Coverage of 4th generation cephalosporins?
Pseudomonas, Enterobacteriaceae , methicillin-susceptible S. aureus, S. pneumoniae., Haemophilus and Neisseria sp.
100
MOA or drawback of 2nd generation cephalosporins?
Not useful against Enterobacter
101
MOA of 3rd generation cephalosporins?
Some able to cross the blood-brain-barrier
Not useful against Enterobacter
No longer commercially available
102
MOA of 4th generation cephalosporins?
Penetrates well into cerebrospinal fluid.
Useful in treatment of Enterobacter infections.
103
WHAT GENERATION DRUGS: Cefazolin, cefadroxil, cephalexin, cephalothin, cephapirin, cephradine
1ST
104
WHAT GENERATION DRUGS: Cefaclor, cefamandole, cefonicid, cefuroxime, cefprozil, loracarbef, and ceforanide
2ND
105
WHAT GENERATION DRUGS: Cefotaxime, ceftazidime, ceftizoxime, ceftriaxone, cefixime
3RD
106
WHAT GENERATION DRUGS: cefpodoxime proxetil, cefdinir, cefditoren pivoxil, ceftibuten, moxalactam, cefoperazone
3RD
107
WHAT GENERATION DRUGS: ceftizoxime, moxalactam, cefoperazone
3RD BUT NOT COMMERCIALLY AVAILABLE
108
WHAT GENERATION DRUGS: cefepime
4th
109
This first-generation parenteral cephalosporin has a longer duration of action and a similar spectrum of action, compared to other first- generation drugs. It penetrates well into bone.
Cefazolin
110
This is the prototype of first-generation, oral cephalosporins. Oral administration twice daily is effective against pharyngitis.
Cephalexin
111
1st generation drugs examples?
Cefazolin
Cefadroxil
Cephalexin
112
This parenteral cephalosporin has a longer half-life than similar agents. It crosses the blood-brain barrier, and it can be used for community- acquired bronchitis or pneumonia in the elderly and for patients who are immunocompromised.
Cefuroxime sodium
113
Administered twice daily, this drug is well absorbed and is active against B-lactamase-producing organisms.
Cefuroxime axetil
114
2nd generation drugs examples?
Cefuroxime sodium
Cefuroxime axetil
115
These are administered orally once daily.
Cefdinir
Cefixime
116
This penetrates well into the CSF.
Cefotaxime
117
This is active against Pseudomonas aeruginosa.
Ceftazidime
118
This drug has the longest half-life of any cephalosporin (6 to 8 hours), which permits once-a-day dosing. High levels of the drug can be achieved in blood and CSF.
Ceftriaxone
119
Ceftriaxone is effective against?
genital, anal, and pharyngeal penicillin-resistant Neisseria gonorrhoeae.
120
Ceftriaxone is excreted in patients with? And it has good penetration into?
renal insufficiency.
good penetration into bone.
121
3rd generation drugs examples?
Cefdinir
Cefixime
Cefotaxime
Ceftazidime
Ceftriaxone
122
This is active against Pseudomonas aeruginosa.
Cefepime
123
4th generation drugs examples?
Cefepime
124
This is active against MRSA,
Ceftaroline
125
Advanced generation drugs examples?
Ceftaroline
126
Adverse reactions of cephalosporins include?
* Renal: interstitial nephritis and tubular necrosis
* Hematologic: Hypoprothrombinemia and bleeding disorders (Cefotetan, cefamandole, cefmetazole, and cefoperazone)
* Others: Local irritation and pain (IM), thrombophlebitis (IV)
127
Resistant to beta-lactamases by some organisms
Monobactam - AZTREONAM
128
Aztreonam coverage is limited to?
aerobic Gr(-) organisms
129
T or F: Penicillin-allergic patients cannot tolerate aztreonam
F, can tolerate without reaction
130
Major toxicity is uncommon and parenteral administration
AZTREONAM
131
What is the coverage of carbapenems?
Gram-negative rods including P. aeruginosa, Gram-positive organisms, and anaerobes
132
Carbapenems are resistant to?
most β –lactamases, ESBL
133
What carbapenems are administered IV?
Doripenem, ertapenem, imipenem, and
meropenem
134
Imipenem is combined with what to inhibit what?
combined with cilastatin which inhibits dehydropeptidases- enzymes in renal tubules that inhibit imipinem.
135
Carbapenems penetrate what well, except?
Penetrate CSF well except ertapenem
136
Excretion of carbapenems are through?
renal, adjust dose in renal insufficiency
137
Vancomycin is isolated from?
bacterium Amycolatopsis orientalis
138
Coverage of vancomycin?
bactericidal against Gram-positive cocci and anaerobes (i.e. Enterococcus faecium); Active against MRSA
139
Similar drug to vancomycin?
Teicoplanin
140
MOA of vancomycin?
binds to D-Ala-D-Ala terminal of peptidoglycan; inhibits transglycosylation
141
Adverse reactions to vancomycin?
red man syndrome
142
Fosfomycin is a _________ inhibitor of ___________
Antimetabolite inhibitor of enolpyruvate transferase
143
Fosfomycin inhibits addition of what to what?
Inhibits addition of phosphoenolpyruvate to UDP-N-acetylglucosamine
144
Coverage of fosfomycin?
gram-positive and gram negative
145
Excretion of fosfomycin?
renal, with urinary concentrations exceeding MICs for most urinary tract pathogens
146
Clinical use of fosfomycin?
uncomplicated cystitis (UTI)
147
Bacitracin was obtained from?
Tracy strain of Bacillus subtilis in 1943.
148
Coverage of Bacitracin?
gram-positive microorganisms
149
MOA of Bacitracin?
Inhibits cell wall formation by interfering with the lipid carrier that transfers peptidoglycan subunits to the growing cell wall
150
Adverse reactions to Bacitracin include?
highly nephrotoxicity when administered systemically
151
Clinical use of Bacitracin include?
topical antibiotic
152
Cycloserine is produced by?
Streptomyces orchidaceous.
153
MOA of cycloserine?
inhibits incorporation of d-alanine into peptidoglycan pentapeptide by inhibiting alanine racemase, which converts l-alanine to d-alanine, and d-alanyl-d-alanine ligase.
154
Pharmacokinetics of Cycloserine?
widely distributed in tissues, excreted in urine
155
Clinical use of Cycloserine?
treatment of tuberculosis caused by strains of Mycobacterium tuberculosis resistant to first-line agents
156
Adverse reactions to cycloserine include?
headaches, tremors, acute psychosis, and convulsions
157
Daptomycin is a fermentation product of?
Streptomyces roseosporus
158
Coverage of Daptomycin?
vancomycin-resistant strains of enterococci and S aureus (VRE, VRSA)
159
MOA of Daptomycin?
depolarization of the cell membrane with potassium efflux and rapid cell death
160
Excretion of Daptomycin?
renal
161
Adverse reactions of Daptomycin include?
myopathy- monitor creatine phosphokinase levels, allergic pneumonitis in patients receiving prolonged therapy (>2 weeks)
162
What antagonizes Daptomycin?
Pulmonary surfactant
163
T or F: Pulmonary surfactant antagonizes daptomycin, and it can be used to treat pneumonia.
F, should not be used to treat pneumonia
164
An antimicrobial drug that can eradicate an infection in the absence of host defense mechanisms; kills bacteria
Bactericidal
165
An antimicrobial drug that inhibits antimicrobial growth but requires host defense mechanisms to eradicate the infection; does not kill bacteria
Bacteriostatic
166
Drugs with structures containing a beta-lactam ring that must be intact for antimicrobial action
Beta-lactam antibiotics
167
Bacterial enzymes (penicillinases, cephalosporinases) that hydrolyze the beta-lactam ring of certain penicillins and cephalosporins
Beta-lactamases
168
Potent inhibitors of some bacterial beta-lactamases used in combinations to protect hydrolyzable penicillins from inactivation
Beta-lactam inhibitors
169
Lowest concentration of antimicrobial drug capable of inhibiting growth of an organism in a defined growth medium
Minimal inhibitory concentration (MIC)
170
Bacterial cytoplasmic membrane proteins that act as the initial receptors for penicillins and other beta-lactam antibiotics
Penicillin- binding proteins (PBPs)
171
Chains of polysaccharides and polypeptides that are cross-linked to form the bacterial cell wall
Peptidoglycan
172
More toxic to the invader than to the host; a property of useful antimicrobial drugs
Selective toxicity
173
Bacterial enzymes involved in the cross-linking of linear peptidoglycan chains, the final step in cell wall synthesis
Transpeptidases
174
Microbial resistance includes?
1. Production of antibiotic-inactivating enzymes
2. Changes in the structure of target receptors
3. Increased efflux via drug transporters
4. Decreases in the permeability of microbes’ cellular membrane to antibiotics
175
Strategies of Chemotherapeutic agents?
1. Use of adjunctive agents that can protect against antibiotic inactivation
2. Use of antibiotic combinations
3. Introduction of new (and often expensive)
chemical derivatives of established antibiotics
4. Efforts to avoid indiscriminate use or misuse of antibiotics
176
Major antibiotics that inhibit cell wall synthesis include?
* Penicillins
* Cephalosporins
177
B-lactam antibiotics inhibit?
cell wall synthesis
178
Drugs that are not as important as beta-lactam drugs include?
* Vancomycin
* Fosfomycin
* Bacitracin
179
What is essential for antibacterial activity seen in penicillins?
beta-lactam ring structure
180
Subclasses of penicillin have additional chemical substituents that confer differences in?
* Antimicrobial activity
* Susceptibility to acid and enzymatic hydrolysis
* Biodisposition
181
Pharmacokinetics of penicillins vary in?
resistance to gastric acid, oral bioavailability, and polar compounds (not metabolized extensively)
182
T or F: Penicillins are excreted unchanged in the feces
F, unchanged in urine
183
Tubular excretion of penicillins are inhibited by?
Probenecid
184
Penicillins partly excreted in bile?
Ampicillin and Nafcillin
185
Ampicillin and Nafcillin plasma half-life is how long?
30 min to 1 h
186
Procaine and Benzathine Penicillin G are given how?
IM
187
Procaine and Benzathine Penicillin G: long or short half lives?
Long
188
Procaine and Benzathine Penicillin G can cross?
BBB with inflamed meninges
189
MOA of penicillins?
Bactericidal
190
How do penicillins inhibit cell wall synthesis?
1. Binding of the drug to specific receptors
(penicillin-binding proteins [PBPs])
located in the bacterial cytoplasmic membrane
2. Inhibition of Transpeptidase enzymes
that act to cross-link linear peptidoglycan chains
3. Activation of autolytic enzymes that cause lesions in the bacterial cell wall
191
If Cross-linked peptidoglycans are damaged, this will result to?
cell lysis (bactericidal)
192
Enzymatic hydrolysis of the beta-lactam ring results in the?
loss of antibacterial activity
193
Formed by most staphylococci and gram (-)
organisms
Beta-lactamases
194
Beta-lactamases are also known as?
Penicillinases
195
Beta-lactamases have am major mechanism for?
bacterial resistance
196
Inhibitors of this enzymes are used in combination with penicillin to prevent their inactivation include?
* Clavulanic acid
* Sulbactam
* Tazobactam
197
Penicillin resistance includes structural changes in?
target PBPs and the porin structure of the outer membrane
198
Other mechanisms of bacterial resistance includes?
* Methicillin resistance in staphylococci
* Penicillin G resistance in pneumococci
199
Narrow-spectrum penicillinase-susceptible
agent that is a prototype, parenteral with a limited spectrum of activity
PENICILLIN G
200
PENICILLIN G is susceptible to?
beta-lactamases
201
PENICILLIN G is useful against infections caused by?
* Streptococci
* Meningococci
* Gram (+) bacilli
* Spirochetes
Penicillin-resistant S. pneumoniae (PRSP) strains
202
Some strains resistant to Pen G via production of beta-lactamases
* S. aureus
* N. gonorrhea
203
Drug of choice for syphilis
PENICILLIN G
204
Narrow-spectrum drug given orally for Oropharyngeal infections
PENICILLIN V
205
Very-narrow-spectrum penicillinase-resistant agents used as a treatment of known or suspected staphylococcal infections
METHICILLIN (prototype), NAFCILLIN, OXACILLIN
206
Has Wider spectrum than pen G, Susceptible to penicillinases
AMPICILLIN and AMOXICILLIN
207
Wider spectrum penicillinase-susceptible
agents include?
AMPICILLIN and AMOXICILLIN
208
AMPICILLIN and AMOXICILLIN have uses similar to Pen G which include?
* Enterococci - L. monocytogenes
* E. coli - P. mirabilis
* H. influenzae - M. catarrhalis
209
Synergistic (1+1=3) with aminoglycosides in enterococcal and listerial infections
AMPICILLIN and AMOXICILLIN
210
Wider spectrum penicillinase-susceptible agents include?
PIPERACILLIN and TICARCILLIN
211
Used against Pseudomonas, Enterobacter
and Some cases of klebsiella species
PIPERACILLIN and TICARCILLIN
212
Maybe caused by direct irritation or by overgrowth of gram (+) organisms or yeasts
Pseudomembranous colitis
213
Cephalosporins with side chains undergo?
hepatic metabolism
214
Major elimination of cephalosporins is via?
renal tubular excretion
215
What cephalosporins are excreted majorly in the bile and what generation are these?
Cefoperazone and ceftriaxone (3rd generation)
216
Which generation cephalosporins do not enter the CSF when the meninges are inflamed?
1st- and 2nd-generation
217
Effective against B.fragilis?
Cefofetan, cefoxitin
218
Effective against H.influenzae or M.catarrhalis?
Cefamandole, cefuroxime, cefaclor
219
3rd generation cephalosporins have the ability to penetrate the blood-brain barrier except?
cefoperazone, cefixime
220
3rd generation cephalosporins are effective against?
S. marcescens
221
Activity against Pseudomonas
Cefoperazone, ceftazidime (3rd gen)
222
Drug of choice for gonorrhea
Ceftriaxone (IV) and cefixime
223
Single injection for acute otitis media
As effective as 10 days of amoxicillin
Ceftriaxone
224
Cefepime effective against?
* Enterobacter
* Haemophilus
* Neisseria
* Some penicillinase-resistant pneumococci
225
Combines the gram (+) activity of 1st gen
and wider gram (-) spectrum of 3rd gen
Cefepime
226
May cause hypoprothrombinemia, and has Disulfiram-like reactions with ethanol
Drugs containing a methlythiotetrazole group: Cefamandole, cefoperazone, cefofetan
227
Monobactam that is resistant to beta-lactamases produced by certain gram (-) rods (Klebsiella, Pseudomonas, Serratia)
ASTREONAM
228
ASTREONAM is resistant to beta-lactamases produced by certain gram (-) rods which are?
* Klebsiella
* Pseudomonas
* Serratia
229
An inhibitor of cell wall synthesis binding to
PBP3
ASTREONAM
230
No cross-allergenicity with penicillin
ASTREONAM
231
Carbepenems that retain the beta-lactam ring
IMIPENEM, MEROPENEM, and ERTAPENEM
232
IMIPENEM, MEROPENEM, and ERTAPENEM are useful against infections caused by?
organisms resistant to other antibiotics
233
Rapidly inactivated by renal dehydropep-
tidases I
IMIPENEM
234
* Administered in combination
* Inhibitor of the enzyme
* Increases the half-life
* Inhibits formation of nephrotoxic metabolites
Cilastatin
235
* Similar to imipenem
* Not metabolized by renal dehydropeptidases
* Less likely to cause seizure
MEROPENEM
236
* Long half-life
* Less active against pseudomonas
* IM injection causes pain and irritation
ERTAPENEM
237
Used in fixed combination with certain hydrolyzable penicillins
CLAVULANIC ACID, SULBACTAM,
and TAZOBACTAM
238
Plasmid-encoded beta-lactamases include?
* Gonococci
* Streptococci
* E. coli
* H. influenzae
239
Bactericidal glycoprotein which binds to the D-Ala-D-Ala terminal of the nascent peptidoglycan pentapeptide side chain
VANCOMYCIN
240
VANCOMYCIN inhibits?
transglycosylation, elongation of peptidoglycan chain and cross-linking
241
Due to decreased affinity of the drug to
the binding site there is replacement of D-Ala by D-lactate
Vancomycin-resistant enterococci (VRE)
and vancomycin-resistant S. aureus
(VRSA)
242
Drug-resistant gram (+) organisms include?
* MRSA
* Penicillin-resistant pneumococci
* C. difficile
243
Not absorbed orally; Maybe given for bacterial enterocolitis
VANCOMYCIN
244
Vancomycin dosage modification in patients with?
renal impairment
245
Fosfomycin resistance happens via?
decreased intracellular accumulation of the drug
246
Antimetabolite inhibitor of cytosolic enolpyruvate transferase that prevents the formation of N- acetylmuramic acid which is essential in peptidoglycan chain formation
FOSFOMYCIN
247
In a single dose of Fosfomycin, the drug is less effective than?
the 7-day course of treatment with fluoroquinolones
248
What is common in Fosfomycin?
Diarrhea
249
Fosfomycin is synergistic with?
beta-lactam and quinolones in specific infections
250
Peptide antibiotic that interferes with a late stage in cell wall synthesis in gram (+) organisms
BACITRACIN
251
BACITRACIN is limited to ____ use only
Topical
252
Antimetabolite that blocks the incorporation of D-Ala into the pentapeptide side chain of the peptidoglycan
CYLCOSERINE
253
CYLCOSERINE is only used in?
TB caused by organisms resistant to first-line antituberculous drugs
254
CYLCOSERINE is potentially?
Potentially neurotoxic causing tremors, seizure and psychosis
