07_Antibiotic Essential Comparisons_Jonathan and Yinka Flashcards

1
Q

Of the Antimetabolites what microorganisms are halted or killed by…
Sulfanilamide?
Trimethoprim?
Isoniazid?

A

Sulfanilamide&raquo_space; wide range of bacteria and protozoa
Trimethoprim&raquo_space; wide range of bacteria and protozoa
Isoniazid&raquo_space; M. tuberculosis (mycobacteria)

Note: Sulfanilamide and Trimethoprim are static.
Isoniazid is cidal

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2
Q
Of the penicillins, what microorganisms are killed by...
Penicillin G and Penicillin V
Ampicillin and Amoxicillin
Tricarcillin
Piperacillin
Methicillin and Oxacillin
A

Penicillin G and Penicillin V&raquo_space; G+ and some G- cocci (meningitis and ypphilis) (note V is acid stable)
Ampicillin and Amoxicillin&raquo_space; G- enteric and most G+ (note ampicilin is acid stable)
Tricarcillin&raquo_space; G- bacilli, P. Aeruginosa, some G-
Piperacillin&raquo_space; G- bacilli, P. Aeruginosa, anaerobes, and some G +
Methicillin and Oxacillin&raquo_space; some G+ (note Oxacillin is acid stable)

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3
Q
Of the Cephalosporins, what microorganisms are killed by...
Cefazolin?
Cefuroxime?
Ceftriaxone?
Ceftazidime?
A

Cefazolin&raquo_space; G+ and some G- enteric
Cefuroxime&raquo_space; more G- and less G+
Ceftriaxone &raquo_space; broad G- and high penetration to blood brain barrier
Ceftazidime&raquo_space; broad G- and P. Aeruginosa

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4
Q

Of the B-lactams, what microorganisms are killed by…
Aztreonam?
Imipenem?

A

Aztreonam&raquo_space; aerobic G- and P. aeruginosa

Imipenem&raquo_space; broadest antimicrobial spectrum

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5
Q

Of the Glycopeptides, what microorganisms are killed by…
Vancomycin?
Cycloserine?
Bacitracin?

A

Vancomycin&raquo_space; G+ multiply resistent enterococcus and MRSA
Cycloserine&raquo_space; M. Tuberculosis (toxic, so 2ndary choice only)
Bacitracin&raquo_space; G+ (toxic, topical)

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6
Q

What microorganisms are killed by Polymyxin B?

A

G- enteric and Pseudomonas

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7
Q

Of the Aminogycosides, what microorganisms are killed by…
Streptomycin?
Gentamycin?

A

Streptomycin&raquo_space; M. Tuberculosis

Gentamycin&raquo_space; doesn’t say

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8
Q

Of the Tetracyclines, what microoganisms are halted by…
Doxycycline?
Tigecycline?

A

Doxycycline and Tigecycline&raquo_space; are affective against a broad spectrum of microorganisms including mycoplasma, rickettsia, chlamydia.

Note: Tigecycline is the most potent tetracycline. It means business.

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9
Q
Of the 50s inhibitors, what microorganisms are halted by...
Erythromycin?
Azithromycin?
Chloramphenicol?
Clindamycin?
Sreptogramins?
A

Erythromycin&raquo_space; G+ similar to penicillin, mycoplasma, and chlamydia.
Azithromycin&raquo_space; broader spectrum than erythromycin (has long half life and high concentration at site of infection due to penetration of macrophages)
Chloramphenicol&raquo_space; some anaerobes, B. fragilis
Clindamycin&raquo_space; G+ moderate anaerobes
Sreptogramins&raquo_space; MRSA and VREF

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10
Q

What microorganism is halted by the Oxazolidinone: Linezolid aka Zyyox?

A

G+
VREF
MRSA

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11
Q

What microorganism is halted (low concentration) or killed (high concentration) by Mupirocin?

A

MRSA, especially nasal MRSA

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12
Q

Of the DNA Replication Inhibitors, what microorganisms are killed by…
Ciprofloxacin and Moxifloxacin (Quinolones)?
Metronidazole (Nitroimidazole)?

A

Ciprofloxacin and Moxifloxacin (Quinolones)&raquo_space; G- enteric baccili, some G+, and P. aeruginosa
Metronidazole (Nitroimidazole)&raquo_space; Anaerobic (Bacteroides) and Protozoa (trichomoniasis and amebiasis)

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13
Q

Of the RNA synthesis inhibitors, what microorganism is killed by Rifampin?

A

Broad spectrum

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14
Q

Other antibiotics not otherwise classified that halt or kill Tuberculosis are?

A

Ethambutol (static)

Pyrazinamide (cidal)

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15
Q
Of the antifungals whic are cidal and which are static...
Amphotericin B (polyene)
Nystatin (polyene)
Fluconazole & Ketoconazole (azole)
Caspofungin (echinocadin)
Flucytosine
A
Amphotericin B (polyene) >> cidal
Nystatin (polyene) >> usually static, cidal at high doses
Fluconazole & Ketoconazole (azole) >> static
Caspofungin (echinocadin) >> cidal
Flucytosine >> static and cidal
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16
Q

Of the antifungals, what microorganisms are halted or killed by…
Fluconazole & Ketoconazole
Caspofungin

A

Fluconazole & Ketoconazole&raquo_space; oral cadidiasis aka thrush, mycoses, tinea versicolor
Caspofungin&raquo_space; aspergillus candida

17
Q
What are the contraindications of...
Isoniazid?
Penicillins?
Vancomycin?
Cycloserine?
Bacitracin?
Polymyxin B?
Streptomycin?
Gentamycin?
Tetracycline & Doxycycline?
Tigecycline?
Chloramphenicol?
Amphotericin B?
Nystatin?
Fluconazole & Ketoconazole?
A

isoniazid&raquo_space; Liver and neurotoxic
Penicillins&raquo_space; allergy
Vancomycin&raquo_space; CN VII and renal toxic
Cycloserine&raquo_space; toxic
Bacitracin&raquo_space; toxic
Polymyxin B&raquo_space; toxic when systemic
Streptomycin and Gentamycin&raquo_space; CN VIII and renal toxic
Tetracycline, Doxycycline, and Tigecycline&raquo_space; changes in GI flora and diarrhea
Chloramphenicol&raquo_space; Lethal, aplastic anemia (rare) => not widely used
Amphotericin B&raquo_space; toxic but used systemically
Nystatin&raquo_space; very toxic
Fluconazole & Ketoconazole&raquo_space; hepatotoxic orally

18
Q

What is the mechanism for…
Sulfanilamide?
Trimethoprim?
Isoniazid?

A

Sulfanilamide&raquo_space; competitively inhibits PABA in folic acid production
Trimethoprim&raquo_space; inhibits DHF reductase
Isoniazid&raquo_space; interpheres with mycolic acid synthesis

19
Q

What is the mechanism for Penicillins, Cephalosporins, and B-lactams?

A

Binds to an inactivates PBP (transpeptidase responsible for peptidoglycan cross-linking)
Requires growth conditions
Uncouples control of autolysins

20
Q

Of the Glycopeptides, what is the mechanism for…
Vancomycin?
Cycloserine?
Bacitracin?

A

Vancomycin&raquo_space; Binds to peptidoglycan precursors, May also permeabilize protoplasts and inhibit RNA synthesis
Cycloserine&raquo_space; Inhibits D-ala conversions in cell wall formation
Bacitracin&raquo_space; Inactivates phosphatase that regenerates active carrier lipid in murein (peptidoglycan) precursor synthesis

21
Q

What is the mechansims for Polymyxin B?

A

Binds to LPS (negatively charged) then to cytoplasmic membrane phospholipids => membrane leakage

22
Q

Of the Aminogycosides, what microorganisms are killed by…
Streptomycin&raquo_space;
Gentamycin&raquo_space;

A

both inhibit the 30S function

at high concentration, strep inhibits initiation complex
gentamycin binds to more than one ribosome protein, so it is not a single step inhibition

23
Q

What is the mechanism for tetracyclines?

A

blocks 30S

24
Q
Of the 50S inhibitors, what is the mechanism of...
Erythromycin
Azithromycin
Chloramphenicol
Clindamycin
Sreptogramins
Note the mechanisms are all similar
A

basically all block chain elongation

25
Q

What is the mechanism of Oxazolidinones Linezolid (Zyvox)?

A

Inhibits tRNA translocation

Interacts with 16S RNA and 23S rRNA of both subunits

26
Q

What is the mechanism on Mupirocin?

A

Binds isoleucyl-tRNA synthetase

27
Q

Of the DNA Replication Inhibitors, what is the mechanism of…
Ciprofloxacin and Moxifloxacin (Quinolones)?
Metronidazole (Nitroimidazole)?

A

Ciprofloxacin and Moxifloxacin (Quinolones)&raquo_space; Inhibits DNA gyrase
Metronidazole (Nitroimidazole)&raquo_space; “Binds and fragments DNA
Reduced and activated by Ferredoxin

28
Q

What is the mechanism of RNA Synthesis Inhibitor Rifampin?

A

Binds to β subunit of bacterial RNAp

29
Q

What is the idiosyncratic mechanism requirement of Pyrazinamide?

A

Requires activity of Mycobacteria amidase

30
Q
Of the anti-fugals what is the mechanism of...
Amphotericin B and Nystatin?
Fluconazole & Ketoconazole?
Caspofungin?
Flucytosine?
A

Amphotericin B and Nystatin&raquo_space; “Bind to sterols in cell membrane => affect permeability, Selective for ergosterol (fungal/plant)”

Fluconazole & Ketoconazole&raquo_space; “Inhibits ergosterol (cell membrane) synthesis via cP450 inhibition
Hyphae synthesis is also inhibited => easily phagocytosed
Caspofungin&raquo_space; Inhibit glucan (cell wall) synthesis via glucan synthase
Flucytosine&raquo_space; “Antimetabolite: replaces uracil => RNA synthesis
Also inhibits thymidylate synthetase => DNA synthesis

31
Q

What are the static antibiotics and anitfungals?

A

Sulfanilamide
Trimethorprim
Tetracyclines
50s Inhibitors: Erythro, Azithro, Chloramphenicol, Clindamycin, Sreptogramins

Linezolid (Oxazolidinones)
Ethanbutol
Nystatin