No abstract

No abstract

No abstract

A long-term cryopreservation study of vegetative cells of Micrococcus lutea ATCC 9341a, Micrococcus lutea ATCC 15957, and Staphylococcus epidermidis ATCC 12228 cells, used in our antibiotic bioassay procedure, was conducted. The cryoprotective abilities of 1% methylcellulose solution and a 15% glycerol solution at −14°C were determined. More organisms remained viable in 1% methylcellulose than in 15% glycerol. Overall survival of Staphylococcus epidermidis ATCC 12228 after 365 days was 1.5 logs lower than the other 2 organisms. The sensitivity and the resistance of the preserved organisms to various antibiotics did not change: The methodology is simple and inexpensive, saves analytical time, and avoids risk of contamination and sudden loss of a well-characterized culture.