Gibco™ antibiotic-antifungal agents are used to prevent bacterial and fungal contamination. This solution contains 10,000 units/mL penicillin, 10,000 µg/mL streptomycin, and 25 µg/mL Gibco Amphotericin B. The antibiotics penicillin and streptomycin have a potent combined antimicrobial effect against Gram-positive and Gram-negative bacteria and are used to prevent bacterial contamination of cell cultures. Amphotericin B inhibits multicellular fungi and yeasts, thereby preventing fungal contamination of cell cultures.

Penicillin was originally purified from the fungus Penicillium. Its mechanism of action is to directly interfere with bacterial cell wall synthesis and indirectly to further change the cell wall by triggering the release of enzymes. Streptomycin was originally purified from Streptomyces griseus. Its mechanism of action is to bind to the 30S subunit of bacterial ribosomes, thereby inhibiting protein synthesis, leading to the death of sensitive bacteria. Amphotericin B is an antifungal agent that inhibits the growth of fungi and yeasts by increasing the permeability of fungal plasma membranes.