n 1  cap  :  a genus of small gram-positive flagellated rod-shaped bacteria that do not form spores, are aerobic or facultatively anaerobic, and have a tendency to grow in chains and that include one (L. monocytogenes) causing listeriosis  2  :  any bacterium of the genus Listeria - called also listerella  lis*te*ri*al adj lis*te*ric adj 
 
 
 
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