Food poisoning bacteria. Coloured scanning electron micrograph (SEM) of Enterococcus sp. bacteria on the surface of a sausage. Species of Enterococcus were previously known as Strepto- coccus. The bacteria (green) are spherical cocci and appear in pairs known as diplococci. They are seen on a background of sausage meat. Meat contaminated with Enterococcus sp. can cause food poisoning in humans. Some Enterococcus sp. are a normal inhabitant of the human intestine, but can also cause urinary tract infections and invade wounds or ulcers on the skin. They show resistance to some types of antibiotics. Magnification: x7,600 at 6x7cm size. Magnification: x26,000 at 10x8 inch print size.