Antimicrobials 1 and 2 Flashcards Preview

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Flashcards in Antimicrobials 1 and 2 Deck (29):
1

Define antibiotic and antimicrobial

Antibiotic: technically a naturally produced chemical from a microorganism. Antibacterial: drugs to treat bacterial infections

2

Define bacteriostatic and bactericidal

Static stops growth so immune system can catch up. Cidal kill bacteria. Best for life-threatening or when immune systems broken.

3

Principles of Antimicrobial Therapy Flowchart.

Insert chart.

4

Betalactams

Only work when the cells are actively dividing

5

Penicillin pyramid

Penicillin most narrow, amoxicillin/ampicillin more, pipercillin most. Cloxacillin on the side only fights staph, some strep. Tunnels = add another drug to amoxicillin/pipercillin. Insert Picture.

6

General facts Cephalosporins

From mold. Blocks cross linking of peptidoglycan, activate autolytic enzymes. Gram -ve coverage increases with generation, gram +ve decreases. No Listeria, no Enterococcus, no coagulase negative staphylococci

7

Generations of cephalosporins

1. Good gram +ve cocci, some gram -ve rod; 2. Good gram +ve cocci, more gram -ve; 3. Not great staph, good strep, even more gram -ve; 4. Good gram +ve, most gram -ve

8

Names of drugs in the generations of cephalosporins

1st: Cefazolin, cephalexin (po). 2nd: Cefuroxime, cefprozil. 3rd: (all T’s) Cefotaxime, ceftazidime, ceftriaxone, cefixime (po). 4th: cefepime

9

Monobactams

Aztreonams. No anaerobes covered.

10

Carbapenems

Imipenem and meropenem (fewer side effects) - cover almost all diseases.

11

Vancomycin

NOT A BETA LACTAM. Acts on early peptidoglycan wall synthesis

12

Bacitracin

NOT A BETA LACTAM. Acts by inhibiting the precursors from getting to the site of peptidoglycan wall synthesis. Only used as a cream/topical agent because of side effects

13

Summary of the drugs that affect cell wall

The cell wall active agents are the penicillins, the cephalosporins, the carbapenems, aztreonam and vancomycin. Penicillins – penicillin tree. Cephalosporins – ceph cycle. Aztreonam only gram negs. Carbapenems - gorillacillin. Vancomycin and bacitracin– only gram pos

14

Protein inhibitors

Need to be actively transported into cell - therefore don’t work well on anaerobes.

15

Aminoglycosides

Protein inhibitor. Gut gram negatives, bacteriocidal.

16

Macrolides/Erythromycins

Protein inhibitor. Mycoplama, chamydia, gram +ve, and respiratory gram -ve . Bacteriostatic.

17

Clindamycin

Protein inhibitor. Bacteriostatic. Common for dental and gyne. Gram positive aerobe and anaerobe

18

Chloramphenicol

Protein inhibitor. Bacteriostatic. Rarely used due to side effects - affect bone marrow and mitochondria.

19

Tetracycline, doxycycline, tigecyclin

Protein inhibitor. Bacteriostatic. Good coverage. Deposit on bones and teeth, can stain.

20

Linezolid

Protein inhibitor. Bacteriostatic. Acts on ribosome. Good for highly resistant gram +ve infections (superbugs)

21

Drugs that affect nucleic acid synthesis.

Work on proteins that affect nucleic acids ie ribosomes, gyrase, other enzymes, etc.

22

Quinolones

Inhibit enzymes for supercoiling (gyrase, etc). 1: rare. 2. Ciprofloxacin (urinary, diarrhea, gram +ve). 3. Levofloxain (pneumonia from community, mostly gram +, some gram -). 4. Gemifloxacin (powerful).

23

Metronidazole

Affect nucleic acid synthesis. Converted to active form by anaerobic or parasites. May be cancerous.

24

Rifampin

Inhibits RNA polymerase. Used in combination for mycobacteria. Prophylaxis against N meningitidis.

25

Antimetabolites

Binary fission requires cofactors like THF and folic acid. Antimetabolites block these.

26

TMP/SMX

Antimetabolites. No anaerobes. coverage good

27

Cytoplasmic membrane agents

Polymyxin - alters permeability; Good for gram -ve rods. Daptomycin - distrupts CM; reserved for highly resistant gram +ve cocci

28

How can bacteria become resistant?

Acquire genes via 3 mechanisms: Conjugation (plasmid). Bacteriophage transduction. Transformation (extracellular DNA)

29

What are the resistance mechanisms?

Block target, change target, fake (different metabolic pathway), attack (breakdown before it can bind), efflux pump