Surfing Motility: A Novel Propulsion-Independent Mechanism for Surface Migration in Salmonella and E. coli .

has been extensively studied and is thought to require flagellar propulsion. Here, we show surface expansion in these species even in the absence of propulsion by the flagella. Instead, movement is tied to fermentation and surface tension: As cells ferment sugars, they create local osmolarity gradients, which generate a wave of fluid on which the cells "surf."