Abstract
We have succeeded in demonstrating and staining the capsule of Neisseria gonorrhoeae by a simple method. The presence of a capsule about the gonococcus has been reported only a few times and not substantiated, so that the Committee for Survey of Research on the Gonococcus and Gonococcal Infections 1 concluded, “The opinion of the majority is that the gonococcus does not form a capsule.’ Israeli 2 using a modified Hiss capsule stain found a clear or lightly stained zone, one to 3 times as wide as the organism; Szelvasi 3 claimed that in older cultures the capsule stained more intensively, although he did not describe the capsule. Recently Almaden 4 mordanted smears by Bailey's method, staining with carbol-fuchsin, and stated that capsules could be found when the organisms were in the mucoid state.
In our work various technics have been tried, and finally Churchman and Emelianoff's 5 method, with modifications, was successful. Absolutely clean slides as used for flagella stains were employed; a drop of a slightly turbid aqueous suspension of the organism was placed at one end of the slide, the slide tilted and the drop allowed to run down and air dry. Then 10 drops of Wright's stain was placed on the slide and, when almost evaporated, washed off with tap water, distilled water, or buffered solution (Clark and Lubs, pH 6.4). To demonstrate capsules by this method a metallic sheen must surface the slide and provide a smooth pink-purple background and not a granular one.
The organisms used were 2 strains of gonococci isolated 2 months previously by Dr. R. D. Reid from clinical cases of gonorrhea. Dr. Reid kindly furnished 24–48-hour cultures grown on either dextrose starch agar or ascitic infusion agar; in the latter case the organisms were washed several times with physiological salt solution to free them of whatever protein material might have come from the medium. These cultures were rechecked for identity: they were Gram negative cocci seen most frequently in the typical biscuit shaped diplococcal form, fermented dextrose and not maltose, formed whitish-grey, translucent, raised colonies with smooth outline, one millimeter in diameter on chocolate-blood infusion agar, and these colonies gave a strong oxidase reaction with the paradimethylanalinemonohydrochloride reagent.
Get full access to this article
View all access options for this article.