Campylobacter jejuni bacterium. Coloured trans- mission electron micrograph (TEM) of a section through a Campylobacter jejuni bacterium. This bacterium can grow in areas where little oxygen is present and causes food poisoning in humans. It is a Gram-negative bacterium which has two hair-like flagella (green) for locomotion. It is a common cause of gastroenteritis in humans, especially children and young adults. Contaminated poultry, meat and milk are sources of infection. Symptoms include fever and acute abdominal pain, followed by watery and often bloody diarrhoea. Recovery is usually rapid. Magnification: x25,000 at 6x6cm size.