This organism is an aerobic, Gram positive rod. It exhibits tumbling motility in a hanging drop preparation. Beta-hemolysis is produced on blood agar.
Special agar is required for stool culture isolation.
The main differentiation from other Gram-positive bacteria is the presence of motility. Clinical Correlation Intracellular in human infections Treatment with ampicillin preferable to penicillin due to intracellular action of ampicillin Gentamicin is used for synergy and combination is bactericidal. None of the cephalosporins are effective against Listeria Organism causes abortion in many species of wild and domestic animals.