Pronounced – bak-teer-ee-um

Bacterium (plural bacteria) is a tiny, living, single-cell microorganism (microorganism requires a microscope to be seen) that reproduces by cell division and usually has a cell wall.

Bacterium can be shaped like a sphere, rod, or spiral, can be found in virtually any environment, and can be beneficial or cause infection and disease.

Good bacteria aid in pollution control by consuming and breaking down organic matter and other pollutants in septic systems, sewage, oil spills, and soils. Bad bacteria in soil, water, or air can cause human, animal, and plant health problems.

Examples of bacterial disease include

• Diphtheria
• Tetanus
• Pertussis
• Haemophilus
• Influenza
• Pneumococcus (pneumonia)