| Antibiotic | Class | Working Conc. | Stock Conc. | Solvent | Storage (Stock) | Target Organisms |
|---|
How to Use the Antibiotic Reference Table
Search: Type an antibiotic name (e.g. Ampicillin), abbreviation (e.g. Kan), or solvent (e.g. water, DMSO) to filter the table instantly.
Filter by type or solvent: Use the filter buttons to show only bacterial antibiotics, antifungal agents, or antibiotics grouped by their stock solvent.
Click any row to expand the full detail panel showing all properties, mechanism of action, stock preparation steps, and important notes.
About Laboratory Antibiotics
Antibiotics are used in molecular biology and microbiology labs primarily as selection agents — to maintain plasmids carrying antibiotic resistance genes and to select for transformed or transfected cells. The correct working concentration is critical: too low leads to incomplete selection; too high can be toxic and affect growth rate.
Volume (stock) = Working conc. × Total volume / Stock conc.
// Example: Ampicillin 100 µg/mL in 500 mL LB broth
Stock = 100 mg/mL (1000×)
Add = 100 µg/mL × 500 mL / 100,000 µg/mL = 0.5 mL stock
// Always add antibiotics AFTER autoclaved media cools to ≤55°C
Important Usage Notes
Always add antibiotics to cooled media (≤55°C) after autoclaving — heat destroys most antibiotics. Filter-sterilize stock solutions through a 0.22 µm membrane; do not autoclave antibiotic stocks. Prepare fresh working solutions when possible, especially for β-lactams (ampicillin, carbenicillin) which degrade rapidly in media.
Resistance Markers in Plasmids
Common plasmid resistance markers and their typical selection concentrations: AmpR (Ampicillin 100 µg/mL), KanR (Kanamycin 50 µg/mL), CmR (Chloramphenicol 34 µg/mL), TetR (Tetracycline 10–15 µg/mL), SpecR (Spectinomycin 100 µg/mL), GentR (Gentamicin 10–15 µg/mL).