15 need-to-know antibiotics

Vancomycin

TARGET: inhibits cell wall synthesis by binding to alanine precursors

ADMINISTRATION: Staphyloccus aureus by injection,

or Clostridium difficile in the GI tract, where it is not absorbed

CLASS: glycopeptide (odd complex class, peptide modified carbohydrate)

Amoxicillin/Ampicillin

TARGET: acts as an irreversible inhibitor of the enzyme transpeptidase, which is needed by bacteria to make the cell wall

ADMINISTRATION: oral, IV, intramuscular

CLASS: penicillin group of beta-lactam; aminopenicillin family

Penicillin G (benzyl) vs V

TARGET: cell wall synthesis: decoy molecule resembles the AAs in the side chains of peptidoglycan, so an enzyme that cross-links instead binds to these drugs instead of the normal AA side chain (competitive inhibitor); D-ala transpeptidation blocked (drugs mimic D-ala-ala bridge)

ADMINISTRATION: IV, oral, intramuscular (injected is #1 in dentistry due to narrow spectrum)

G = IV

V = by mouth

CLASS: B-lactams

*Penicillin G AKA benzylpenicillin was first discovered

*Penicillin V (VK) AKA phenoxymethylpenicillin

Augmentin

Amoxicillin & clavulanic acid combo drug

*clavulanic acid is a B-lactamase inhibitor

Trimethoprim

TARGET: nucleic acid inhibitor; works by blocking folate metabolism through inhibiting dihydrofolate reductase thereby inhibiting purine and pyrimidine synthesis

ADMINISTRATION: oral

CLASS: other (usually paired with Sulfonamide, important in facial injuries, readily enters CSF for meningitis)

Sulfamethoxazole

combination of two antibiotics: sulfamethoxazole and trimethoprim

Ciprofloxacin (Levofloxacin)

TARGET: nucleic acid synthesis inhibitors; inhibit DNA gyrase, thus blocking DNA replication

ADMINISTRATION: By mouth, intravenous, topical (ear drops, eye drops) (Dr. G specifically mentioned orally)

CLASS: fluoroquinolones (2nd generation)

Nalidixic Acid

TARGET: nucleic acid synthesis inhibitors; inhibit DNA gyrase, thus blocking DNA replication

ADMINISTRATION: oral

CLASS: fluoroquinolones (1st generation)

Metronidazole

TARGET: DNA inhibitor; gets metabolized by anaerobic bacteria into a very active nitrogen radical that attacks and modifies everything around it, DNA damage results in cell death

ADMINISTRATION: by mouth, topical, rectal, IV, vaginal

CLASS: nitroimidazoles

*antibiotic and antiprotozoal medication

Rifampicin

TARGET: prevents initiation of RNA synthesis at first phospho-diester bond; inhibits bacterial DNA-dependent RNA synthesis by inhibiting bacterial DNA-dependent RNA polymerase

ADMINISTRATION: oral, IV

CLASS: rifamycin derivatives, which is a subclass of anamycins

Streptomycin

TARGET: protein synthesis inhibition; Anti-30S ribosomal subunit

ADMINISTRATION: intramuscular, intravenous (carbohydrate structure would cause it to be digested if ingested)

CLASS: Aminoglycosides

Tetracycline/Tigecycline

TARGET: inhibits protein synthesis: inhibits aminoacyl RNA-binding; inhibits peptidyl transfer by blocking peptidyl transferase site

ADMINISTRATION: oral

CLASS: tetracyclines (new glycylcyclines- Tigecycline)

Azithromycin

TARGET: protein synthesis inhibition; binds the 23S rRNA of the 50S subunit, inhibits chain translocation

ADMINISTRATION: oral, intravenous, eye drop

CLASS: macrolides

*top-used antibiotic

Erythromycin

TARGET: protein synthesis inhibition; binds the 23S rRNA of the 50S subunit, inhibits chain translocation

ADMINISTRATION: oral

CLASS: macrolide

*#2 used dental antibiotic for when patient has allergy to B-lactams

Clindamycin

TARGET: protein synthesis inhibitor by inhibiting ribosomal translocation,[56] in a similar way to macrolides. It does so by binding to the 50S rRNA of the large bacterial ribosomesubunit

ADMINISTRATION: By mouth, topical, IV, intravaginal

CLASS: lincosamides

*reserve for bone infections, careful use, lower dose