Preliminary studies in the clinical use of a bicarbonate containing growth medium for Neisseria gonorrhoeae

A recent study from our laboratory demonstrated that the gaseous carbon dioxide atmosphere used for growth of Neisseria gonorrhoeae could be replaced by the addition of sodium bicarbonate directly to the growth medium. A comparative growth study was initiated using the Transgrow system and the bicarbonate system, Nei-Carb. The Nei-Carb system displayed several obvsiou advantages over the Transgrow system. It required less incubation space, the bicarbonate concentrations can be regulated more readily than concentration of gaseous CO2, and individual plates can be examined without disturbing the atmosphere of other incubating plates. The preliminary results indicate that the Nei-Carb system can be utilized as a medium for primary isolation of gonococci. For every positive culture detected by the Transgrow system a corresponding positive culture was detected by the Nei-Carb system. Moreover, four strains of N gonorrhoeae grew in the Nei-Carb system that would not grow in the Transgrow system using gaseous CO2. On further examination of these strains it was found that they required a much higher concentration of bicarbonate for growth than did those which grew readily in a gaseous CO2 atmosphere.