Microbio antibiotics general Flashcards Preview

Microbiology Quiz 1 > Microbio antibiotics general > Flashcards

Flashcards in Microbio antibiotics general Deck (28)
Loading flashcards...
1

Trimethoprim resistance

Plasmid-coded, trimethoprim-resistant dihydrofolate reductase.

2

Penicilllin resistance

Hydrolysis of ß-lactam ring by ß-lactamase enzyme; decreased Cephalosporins permeability of bacteria to the antibiotic; altered penicillin binding proteins

3

Methicillin resistance

Altered penicillin binding proteins (not in ß-lactamase). (a ß-lactamase-resistant penicillin).

4

Aminoglycosides resistance

Enzymatic modification of drug by plasmid-coded enzyme; decreased permeability of bacteria to the antibiotic; mutation alters site to which antibiotic normally binds (e.g. S12 ribosomal protein for streptomycin).

5

Tetracyclines resistance

Interference with transport of drug into cell.

6

Chloramphenicol resistance

Detoxification of drug by acetylation of hydroxyl.

7

Erythromycin resistance

Enzymatic methylation of 23S ribosomal RNA.

8

Ciprofloxacin, Rifampin resistance

Altered target enzymes (gyrase, RNAP)

9

Vancomycin resistance

Alteration of cell wall precursor target.

10

antimetabolites (sulfonamides, trimethoprim) mechanism of action

Inhibit synthesis of dihydrofolate, ultimately nucleic acid synthesis.

11

Antimetabolite (flucytosine) mechanism of action

inhibits thmidylate synthetase and ultimately DNA synthesis

12

Isoniazid mechanism of action

Inhibits synthesis of mycolic acid (specific for Mycobacteria).

13

b-Lactams (penicillins, cephalosporins) mechanism of action

Interfere with cell wall biosynthesis. Inhibition of transpeptidation weakens cell wall. Autolytic enzymes of bacteria then promote lysis.

14

Glycopeptides (cycloserine, bacitracin, vancomycin, teichoplanin, caspofungin) mechanism of action

Interfere with cell wall biosynthesis.

15

Polymyxins and polyenes (nystatin, amphotericin B daptomycin) mechanism of action

Disrupt membrane integrity.

16

Aminoglycosides (streptomycin) mechanism of action

Inhibit protein synthesis by binding to a specific protein of 30S ribosomal subunit.

17

Aminoglycosides (gentamicin, kanamycin neomycin, amikacin tobramycin) mechanism of action

Bind to 30S ribosomal subunit at multiple sites. Inhibit protein synthesis.

18

tetracyclines mechanism of action

Block protein synthesis by inhibiting binding of amino-acyl t-RNA to 30S subunit.

19

Macrolides (Erythromycin, azithromycin), clindamycin, chloramphenicol mechanism of action

bind to 50S ribosomal subunit. Inhibit protein synthesis at chain
elongation step.

20

Oxazolidinones (linezolid) mechanism of action

Bind rRNA on both ribosomal subunits (new)

21

Streptogramins (dalfopristin, quinupristin) mechanism of action

Bind to 50S ribosomal subunit (new)

22

Mupirocin mechanism of action

Binds isoleucyl tRNA synthetase, preventing charging of Ile-tRNA and thus affecting protein synthesis.

23

Fluoroquinolones ciprofloxacin mechanism of action

Inhibit bacterial DNA gyrase.

24

Nitroimidazoles mechanism of action

fragments DNA

25

Rifampin mechanism of action

binds to bacterial RNA polymerase and blocks transcription

26

Azoles (fluconazole, ketoconazole) mechanism of action

Inhibit ergosterol synthesis.

27

Ethambutol mechanism of action

unknown, anti-TB

28

Pyrazinamide mechanism of action

unknown, anti-TB