ID#: 8172
Description: Caption:
This 1977 image depicted two Petri dishes, each filled with trypticase soy agar medium, containing 5% defibrinated sheep's blood. The plate on the left had been stabbed and streaked with an inoculum containing Streptococcus mitis, alpha-hemolytic bacteria, a member of the Viridans group, while the right plate was stabbed with an inoculum containing Group A Streptococcus pyogenes (GAS), a typical beta-hemolytic bacteria. The inoculation was performed using a wire loop, which had been dipped into a primary culture medium. The BAPs were incubated in a carbon dioxide enriched atmosphere at 35oC for 24-hours.
Additional Information:
All culture organisms were Gram-positive cocci bacteria. The alpha-hemolytic organisms in the left plate grew colonies that were surrounded by a hazy, indistinct zone of partial red blood cell (RBC) hemolysis, and the beta-hemolytic bacteria on the right grew colonies surrounded by a clear, colorless zone of complete RBC destruction. Using the "stabbing" method of inoculation makes the qualitative interpretation of the hemolytic reaction much easier, for the results of colonial interactivity with the blood agar medium is much more pronounced, and therefore, easier to discern.
High Resolution: Click here for hi-resolution image (6.53 MB)
Content Providers(s): CDC/ Richard R. Facklam, Ph.D.
Creation Date: 1977
Photo Credit:
CDC Organization
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Copyright Restrictions: None - This image is in the public domain and thus free of any copyright restrictions.