Nutritional Profiles of Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica in Chemically Defined Media and the Use of Growth Requirements for Gonococcal Typing
A chemically defined medium was developed that supports growth of various strains of Neisseria recently isolated from clinical material. Quantitative tests were made of seven strains of Neisseria gonorrhoeae cultivated in the defined fluid medium. When inoculated at concentrations of 2 × 105–6 × 106 cfu/ml, the gonococci multiplied with generation times ≤ 60 min, yielding about 5 × 108 cfu/ml within 10 hr and more than 109 cfu/ml by 24 hr. Defined agar media were used for investigation of the growth requirements of 146 strains of N. gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica. Each species has a distinctive nutritional profile that serves to differentiate and identify it. On a series of defined media lacking different groups of compounds, the meningococci were relatively homogeneous in their growth responses and were more competent biosynthetically than strains of the other species. Gonococci exhibited a diversity of nutritional requirements; 74 strains were subdivided into 13 distinct clusters (auxotypes) on the basis of their patterns of growth responses to thiamine pyrophosphate, thiamine, proline, arginine, methionine, isoleucine, and hypoxanthine. Such results demonstrate the feasibility of developing a system for auxotyping of clinical isolates of N. gonorrhoeae.