The antibiotics penicillin and streptomycin are used to prevent bacterial contamination of cell cultures due to their effective combined action against gram-positive and gram-negative bacteria. Penicillin was originally purified from the fungi Penicillium and acts by interfering directly with the turnover of the bacterial cell wall and indirectly by triggering the release of enzymes that further alter the cell wall. Streptomycin was originally purified from Streptomyces griseus. It acts by binding to the 30S subunit of the bacterial ribosome, leading to inhibition of protein synthesis and death in susceptible bacteria. This solution contains 10,000 units/mL of penicillin and 10,000 g/mL of streptomycin in a 10 mM citrate buffer (for pH stability).

Life Technologies offers a wide range of antibiotics and antimycotics in both powder and liquid formats. See the complete list, or find products for:
 Contamination control
 Eukaryotic and bacterial selection

See recommended working concentrations for selection antibiotics.

Learn more about the use of antibiotics and antimycotics in cell culture and review guidelines for decontaminating cultures.