Antibiotic Classes Overview

Antibiotic classes can be divided into several different categories, usually based on a common chemical structure. An overview of the classes are described below. For a PDF version of this page, please click here.

Amoxicillin

B-lactams

Widely used antibiotic. All contain a lactam ring.

EXAMPLES: penicillins (amoxicillin and flucloxacillin), cephalosporins (cephalexin)

MoA: Prevent bacteria cell wall biosynthesis

Streptomycin

Aminoglycosides

Family of over 20 antibiotics; all contain aminosugar substructures.

EXAMPLES: streptomycin, neomycin, kanamycin, paromycin

MoA: inhibit the bacterial synthesis of proteins, leading to cell death

Chloramphenicol

Chloramphenicol

Commonly used in low-income countries. Distinct individual compound.

MoA: Inhibit protein synthesis, which prevents growth. Not a first-line drug in developed nations anymore due to increased resistance and safety concerns.

Bleomycin

Glycopeptides

“Drugs of last resort”. Consists of carbohydrate linked to a peptide formed of amino acids.

EXAMPLES: bleomycin, vancomycin, teicoplanin

MoA: Inhibit bacteria cell wall biosynthesis.

Geldanamycin

Ansamycins

Can also demonstrate antiviral activity. all contain an aromatic ring bridged by an aliphatic chain.

EXAMPLES: geldanamycin, rifamycin, naphthomycin

MoA: Inhibit bacterial synthesis of RNA, leading to cell death.

Dalfopristin, a component of quinupristin/dalfopristin

Streptogramins

2 groups of antibiotics that act synergistically. Combination of 2 structural differing compounds, from groups denoted A & B.

EXAMPLES: pristinamycin IIA & IA

MoA: Inhibit the synthesis of proteins by bacteria, leading to cell death.

Sulfamethoxazole

Sulfonamides

1st commercial antibiotics. Contains sulfonamide group. Can cause allergic reactions in some patients.

EXAMPLES: prontosil, sulfanilamide, sulfadiazine, sulfisoxazole

MoA: Prevent bacterial growth and multiplication (does not kill bacteria).

Tetracycline hydrochloride

Tetracyclines

Becoming less popular due to increased resistance. All contain 4 adjacent cyclic hydrocarbon rings.

EXAMPLES: tetracycline, doxycycline, limecycline, oxytetracycline

MoA: inhibit protein synthesis by bacteria, preventing growth

Erythromycin

Macrolides

2nd most prescribed antibiotics. All contain a 14-, 15-, or 16-membered macolide ring.

EXAMPLES: erythromycin, clarithromycin, azithromycin

MoA: inhibit protein synthesis by bacteria, occasionally leading to cell death.

Linezolid

Oxazolidinones

Potent antibiotics, typically used as drugs of last resort. All contain 2-oxazolidone somewhere in the structure.

EXAMPLES: linezolid, posizolid, tedizolid, cycloserine

MoA: inhibit protein synthesis by bacteria, occasionally leading to cell death.

Ciprofloxacin

Quinolones

Resistance evolves rapidly. All contain fused aromatic rings with a caroboxylic acid group attached.

EXAMPLES: ciprofloxacin, leofloxain, trovafloxivin

MoA: intefere with bacteria DNA replication and transcription.

Daptomycin

Lipopeptides

Instances of resistance are rare. All contain a lipid bonded to a peptide

EXAMPLES: daptomycin, surfactin

MoA: disrupt multiple cell membranes function, leading to cell death.