A 30 year old woman with a bad obstetric history presents with fever. The blood culture from the patient grows gram--positive small to medium coccobacilli that are pleomorphic, occurring in sho chains. Direct wet mount from the culture shows tumbling motility. The most likely organism is:
High-Yield Explanation
Listeria are small gram positive coccobacilli with characteristic tumbling motility. They are non motile at 38 degree Celsius as the flagellae are produced optimally at 20-30 degree Celsius. Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition