Modified Dextrose Starch Agar for the Preservation of Neisseria gonorrhoeae

ABSTRACT

To seek a practical and inexpensive method to preserve gonococcal cultures, a few methods were compared. The following methods kept the cultures alive for only a short period of time skim milk at -20 degrees C; tryptic soy broth with 15% glycerol at -20 degrees C; cystine tryptic agar at 35 degrees C. Most of the test cultures survived for more than 4 weeks in the following media one half strength dextrose starch agar; one half strength dextrose starch agar with ferric nitrate; one half strength dextrose starch agar with antimicrobic CNV. Dextrose starch agar could be substituted by GC medium base with a slight modification. It is concluded that preservation of gonococci in one half strength dextrose starch agar with CNV, which produces less frequent contamination, is a practical method to maintain cultures for teaching and quality control.