Capillary precipitin typing of Streptococcus pneumoniae

Abstract

The Neufeld test is presently the method of choice for typing S. pneumoniae. Although the test is reliable and relatively easy to perform, a simpler test, not requiring microscopic examination, would facilitate large-scale testing. A capillary precipitin test was designed and tested for its usefulness in typing penumococci. The type-specific carbohydrate antigens were obtained from broth culture supernatants. The antigens were reacted with type-specific [rabbit] antisera in glass capillary pipettes. Results from 82 reference antigens and 166 antigens from diagnostic pneumococcal strains showed that the reactions were specific, and the results agreed with Neufeld test results. These results indicate that the precipitin test is as specific as the Neufeld test. The test is easy to perform, requires small amounts of antiserum and can be completed in a short period of time.