6. Interpreting test results. On the basis of the test results, identify as B. cereus those isolates which are actively motile and strongly hemolytic and do not produce rhizoid colonies or protein toxin crystals. Nonmotile B. cereus strains are also fairly common and a few strains are weakly hemolytic. These nonpathogenic strains of B. cereus can be differentiated from B. anthracis by their resistance to penicillin and gamma bacteriophage. CAUTION: Nonmotile, nonhemolytic isolates that are suspected to be B. anthracis should be submitted to a pathology laboratory such as the Centers for Disease Control and Prevention, Atlanta, GA, for identification or destroyed by autoclaving. Acrystalliferous variants of B. thuringiensis and nonrhizoid strains derived from B. mycoides cannot be distinguished from B. cereus by the cultural tests.