bacteri(o)- Also bacter-.
[English bacterium, from Greek baktērion, diminutive of baktēria, staff or cane (because the first bacteria to be discovered were rod-shaped).]
Bacteria are members of a large group of single-celled micro-organisms, including some which can cause disease. Bacteriology is the study of them; a bactericide is a substance which kills them; a bacteriophage (Greek phagein, eat) is a virus which attacks bacteria; a bacteriostat (Greek statos, standing) is a substance that prevents the multiplying of bacteria without destroying them; bacteraemia (US bacteremia) is the presence of bacteria in the blood, while bacteriuria is their presence in the urine. See also bacill-.