Translations available in Spanish. Bacitracin Sensitivity Using Group A and B Beta-Hemolytic Streptococci Resource Type: Visual: Image Publication Date: Prior to 1/1/2002 Figure 1 Streptococcus pyogenes and Streptoccocus agalactiae (Enlarged view) Streptococcus pyogenes and Streptoccocus agalactiae (Labeled view) Authors Neal Chamberlain Department of Microbiology/Immunology A.T. Still University of Health Sciences/KCOM Kirksville, Missouri 63501 USA Email: nchamberlain@atsu.edu The image is a 24 h culture on 5% sheep blood agar plate that has been streaked with two different beta-hemolytic streptococci. One is a group A streptococcus (S. pyogenes) the other is a group B streptococcus (S. agalactiae). This image can be used to demonstrate to students the ability to differentiate the group A beta-hemolytic streptococcus from other non-group A beta-hemolytic streptococci using sensitivity to bacitracin (Taxo A discs). It demonstrates that the group A streptococci are sensitive to bacitracin and the group B streptococci are not sensitive. Age of culture is 24 h.