Most of the types of bacteria that are not classified as dangerous organisms. However, some species belonging to pathogenic bacteria can cause disease. According to its shape, pathogenic bacteria are divided into three groups. Coccus-shaped bacteria and can cause a hoarse throat, ulcers, and pneumonia. Elongated rod-shaped bacteria hasilus that can cause typhoid and salmonella. Spirokaeta spiral-shaped bacteria and can cause Lyme disease and syphilis.
Bacteria infiltrate into the body through various ways, namely through the sprinkling of water is inhaled from the air, the skin wound, water or food that is swallowed, and reproductive systems. When bacteria enter the body successfully, the bacteria eat, splitting, and release toxic substances that can harm human cells. Usually the immune system can recognize bacteria and destroy it immediately. Infection also can be treated with antibiotics. Bacterial infections can be prevented by immunization, personal hygiene, including clean drinking water, and clean the wound with antiseptic.