Neutrophil cell trapping bacteria Coloured scanning electron micrograph SEM of bacteria rodshaped being trapped by a neutrophil cell The neutrophil cell a type of white blood cell has trapped the bacteria with extruded material that forms a netlike structure called a NET neutrophil extracellular trap This method of cellular defence was first discovered in These are Shigella sp bacteria one of the causes of dysentery a severe intestinal inflammation