No abstract

No abstract

No abstract

A problem central to the study of mycoplasma has been the classification of strains and the identification of isolates from clinical material. Several serologic approaches to the identification of mycoplasma have been employed by laboratories in recent years. These approaches have permitted the recognition of new species of mycoplasma which were indistinguishable from established species in biologic properties.Recently we developed a new serologic technique which can be used for identification of mycoplasrna and for serodiagnosis and seroepidemiology. It is based upon Jensen's observation that specific antiserum inhibited the reduction of tetrazoliurn by Mycoplasma pneumoniae in broth medium.' We modified Jensen's method by incorporating substrates such as glucose, arginine, or urea in the medium as indicators of mycoplasma growth.-In this manner, antibody for all of the human mycoplasma species and many of the animal strains can now be measured by metabolic-inhibition (MI) techniques.Metabolic-inhibition Techniques. Strains of "classical" mycoplasma can be divided into two groups on the basis of whether or not they produce acid from carbohydrates. Acid production causes an acid shift in the pH of the medium. Almost all of the non-acid-producing strains metabolize the amino acid arginine with the release of ammonia into the medium and a concomitant alkaline shift in the pH. Acid or alkaline pH shift can be visualized by the incorporation of phenol red in the medium. In our tests, Haflick's medium6 supplemented with glucose was adjusted initially to pH 7.8, whereas medium supplemented with arginine was adjusted to pH 7.0. Specific antiserum inhibited metabolism of the mycoplasma and prevented an acid or alkaline shift in pH. The highest dilution of antiserum which prevented pH change (color change) was considered 8s the MI antibody end point. For maximum sensitivity, it was necessary to record the MI antibody titer when controls containing mycoplasma but not antiserum had changed approximately 0.5 pH unit, The MI titer of immune serum was not related to the size of the mycoplasma inoculum if the titer was recorded when