07_Antibiotic Essential Comparisons_Jonathan and Yinka Flashcards Preview

M1 Micro Bacteriology Quiz 1 > 07_Antibiotic Essential Comparisons_Jonathan and Yinka > Flashcards

Flashcards in 07_Antibiotic Essential Comparisons_Jonathan and Yinka Deck (31)
Loading flashcards...
1

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

Sulfanilamide >> wide range of bacteria and protozoa
Trimethoprim >> wide range of bacteria and protozoa
Isoniazid >> M. tuberculosis (mycobacteria)

Note: Sulfanilamide and Trimethoprim are static.
Isoniazid is cidal

2

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

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

3

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

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

4

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

Aztreonam >> aerobic G- and P. aeruginosa
Imipenem >> broadest antimicrobial spectrum

5

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

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

6

What microorganisms are killed by Polymyxin B?

G- enteric and Pseudomonas

7

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

Streptomycin >> M. Tuberculosis
Gentamycin >> doesn't say

8

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

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

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

9

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

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

10

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

G+
VREF
MRSA

11

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

MRSA, especially nasal MRSA

12

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

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

13

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

Broad spectrum

14

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

Ethambutol (static)
Pyrazinamide (cidal)

15

Of the antifungals whic are cidal and which are static...
Amphotericin B (polyene)
Nystatin (polyene)
Fluconazole & Ketoconazole (azole)
Caspofungin (echinocadin)
Flucytosine

Amphotericin B (polyene) >> cidal
Nystatin (polyene) >> usually static, cidal at high doses
Fluconazole & Ketoconazole (azole) >> static
Caspofungin (echinocadin) >> cidal
Flucytosine >> static and cidal

16

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

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

17

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

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

18

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

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

19

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

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

20

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

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

21

What is the mechansims for Polymyxin B?

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

22

Of the Aminogycosides, what microorganisms are killed by...
Streptomycin >>
Gentamycin >>

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

What is the mechanism for tetracyclines?

blocks 30S

24

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

basically all block chain elongation

25

What is the mechanism of Oxazolidinones Linezolid (Zyvox)?

Inhibits tRNA translocation
Interacts with 16S RNA and 23S rRNA of both subunits

26

What is the mechanism on Mupirocin?

Binds isoleucyl-tRNA synthetase

27

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

Ciprofloxacin and Moxifloxacin (Quinolones) >> Inhibits DNA gyrase
Metronidazole (Nitroimidazole) >> "Binds and fragments DNA
Reduced and activated by Ferredoxin

28

What is the mechanism of RNA Synthesis Inhibitor Rifampin?

Binds to β subunit of bacterial RNAp

29

What is the idiosyncratic mechanism requirement of Pyrazinamide?

Requires activity of Mycobacteria amidase

30

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

Amphotericin B and Nystatin >> "Bind to sterols in cell membrane => affect permeability, Selective for ergosterol (fungal/plant)"

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