Helicobacter pylori. Coloured transmission electron micrograph (TEM) of a Helicobacter pylori bacterium (formerly known as Campylobacter pyloridis). Colonies of H.pylori occur on the stomach mucous membrane in people suffering gastritis, and this bacteria has been linked to stomach ulcer formation.
Campylobacter bacteria are the number-one cause of food-related gastrointestinal illness in the United States. ARS scientists are currently sequencing multiple Campylobacter genomes. This scanning electron microscope image shows the characteristic spiral, or corkscrew, shape of C. jejuni cells and related structures. Photo by De Wood; digital colorization by Chris Pooley.
Staphylococcus bacteria. Most common of the 1 trillion bacteria that live on our skin. Only a few strains of this bacteria are harmful and cause staph infections or toxic shock syndrome. Most are harmless.