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.
Antibiotic Classes Overview
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.
