Antimicrobial Agents

Bactericidal agents ______ bacteria.

kill

Bacteriostatic agents ______ bacteria.

inhibit growth of

Bacteriostatic agents need the ______ to work with it to eliminate bacteria.

immune system

Antimicrobial agents are classified by their ______.

target site

What are the five main categories of antimicrobial agents (by target)?

- Cell wall

- Cell membrane

- Protein synthesis

- Nucleic acid synthesis

- Metabolic processes

What are the two antimicrobial agents that inhibit cell wall synthesis?

Beta-lactams and glycopeptides

Beta-lactams target ______ organisms.

Gram +/-

Beta-lactams and glycopeptides target the linkage of ______ in cell wall synthesis.

D-alanine to D-alanine

Beta-lactams inhibit the ______ that create the cross-linkage between peptide chains.

PBPs (transpeptidases)

This causes the bacterial cell to ______.

lyse (kill itself)

What are the major classes of Beta-lactam antibiotics?

- Penicillin

- Cephalosporins

- Monobactams

- Carbapenems

Penicillins all end in ______.

-cillin

Cephalosporins all start with ______.

cef-/ceph-

What antibiotic is a monobactam?

Aztreonam

Carbapenems all end in ______.

-enem

Glycopeptides bind to the ______ of transpeptidation enzyme.

substrate

Glycopeptides act only against ______ organisms.

Gram +

What are the two glycopeptides?

Vancomycin and teicoplanin

Vancomycin and teicoplanin are too ______ to fit through gram negative porins.

large

What are the antimicrobials that act on the cell membrane?

- Polymyxins

- Bacitracin

- Lipopeptide (Daptomycin)

Polymyxins include _______ and _______.

polymyxin B, colistin

Polymyxins alter the cell membrane's permeability by interacting with the membrane's ______.

phospholipids

Bacitracin disrupts the cell membrane and interferes with ______ synthesis.

cell wall

Bacitracin targets ______ bacteria while polymyxins target ______.

gram +, gram - rods

Lipopeptide (Daptomycin) binds to cytoplasmic membrane and ______.

aggregates

This aggregation of lipopeptide changes the shape of the membrane, forming ______.

holes

Lipopeptide is active against ______ bacteria only.

gram +

Lipopeptide is used to treat cases of ______ and ______ bacteriemia.

MRSA, VRE

What are the antimicrobial categories that inhibit protein synthesis?

- Rifampin (Rifampicin)

- Aminoglycosides

- Tetracyclines

- Macrolides

- Lincosamides

- Chloramphenicol

Rifampin is active against ______ bacteria and ______.

gram +, mycobacteria

Aminoglycosides are bactericidal and used against ______ bacteria.

gram -

Aminoglycosides are used in conjunction with ______ for gram + bacteria.

beta-lactams

What are some aminoglcyosides?

- Streptomycin

- Gentamicin

- Tobramycin

- Amikacin

Tetracyclines are bacteriostatic and have a ______ spectrum of activity.

broad

Are macrolides bacteriostatic or bactericidal?

Mostly bacteriostatic, but can be bactericidal at high concentrations

What are the macrolides?

- Erythromycin

- Clarithromycin

- Azithromycin

Macrolides are active mostly against ______ bacteria and are used when patients are allergic to ______.

gram +, beta-lactams

Lincosamides are active against ______ organisms and anaerobes.

gram +

What are the lincosamides?

- Clindamycin

- Lincomycin

Chloramphenicol is broad spectrum, acting against ______ bacteria.

gram + and -

What are the antimicrobial categories that inhibit synthesis of nucleic acid precursors?

- Sulfonamides

- Trimethoprim

Sulfonamides and trimethoprim inhibit production of ______ from PABA, which is needed for ______ synthesis.

folic acid, purine

What are the antimicrobials that inhibit DNA function?

- Quinolones

- Fluoroquinolones

- Metronidazole

Quinolones include ______.

nalidixic acid

Fluoroquinolones include ...

- Ciprofloxacin

- Levofloxacin

- Gattifloxacin

- Moxifloxacin

Quinolones and fluoroquinolones inhibit DNA ______ and ______.

gyrase, topoisomerase IV

Fluoroquinolones are ______, while quinolones target ______ bacteria only.

broad spectrum, gram -

Metronidazole makes DNA ______, targeting anaerobes and protozoans.

unstable

What are some newer antimicrobial agents?

- Streptogramins

- Oxazolidinones

- Ketolides