Biomedical Sciences ETDs

Publication Date



Accurate and rapid identification of group A beta-hemolytic streptococci in upper respiratory infections is a vital step toward the appropriate treatment and eventual prevention of sequelae of streptococcal diseases. Presently, identification of group A streptococci may be accomplished in one of two ways: 1) serologically, by the Lancefield precipitin test, or by the fluorescent antibody test, and 2) by the bacitracin sensitivity disc test, or biochemically. Both the precipitin test and the bacitracin disc plate method take approximately 24-48 hours for identification of streptococci. The fluorescent antibody test requires less than 24 hours. Comparative studies have demonstrated that the conventional fluorescent antibody technique is as sensitive as the bacitracin disc method for identification of group A streptococci while the fluorescent antibody technique is more rapid. The intent of this study is to evaluate a rapid fluorescent antibody technique and compare it to the bacitracin disc method for the identification of group A streptococci. The precipitin test was used to arbitrate discrepancies between the two tests under study. A modified pronase-autoclave extraction procedure for the recovery of groupable carbohydrate antigen was employed in the precipitin test. The simple, efficient method eliminates the use of many chemicals, requires no pH determination and requires only small volumes of culture. Seven hundred and two throat cultures were obtained from patients at the Bernalillo County Medical Center in Albuquerque, New Mexico. They were tested for the presence of group A streptococci by a rapid fluorescent antibody test and the bacitracin disc plate test. Comparison of the two tests indicated that the fluorescent antibody test was more specific and sensitive than the bacitracin disc test and was a more rapid means of achieving accurate identification of group A streptococci. The sensitivity, rapidity and simplicity of the rapid fluorescent antibody test for the identification of group A streptococci from 2-4 hour broth cultures make this a suitable procedure for application in most diagnostic laboratories.

Document Type




Degree Name

Biomedical Sciences

Level of Degree


Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

John August Ulrich

Second Committee Member

Sei Tokuda

Third Committee Member

Alice Huston Cushing