Bacteria are usually composed of a cell wall, a cell membrane, a cytoplasm and a nucleus. Usually the basic forms of bacteria consist mainly of cocci (e.g., Staphylococcus), bacilli (e.g., Escherichia coli), and spirochetes (e.g., Helicobacter pylori).Bacteria have the structure and function of a typical prokaryotic cell, wherein each bacterial cell has a cell wall, a cell membrane, a cytoplasm, and a nucleoplasm, which are referred to as the basic structures of bacteria. Pods, flagella, hyphae and bacteriophages are specialized structures of some bacteria. Generally bacteria are a kind of unicellular microorganisms, belong to prokaryotes, they are small, simple structure, have cell wall and primitive nucleoplasm, no nucleolus and nuclear membrane, no other organelles except ribosomes. If patients find bacterial infection, they should seek medical treatment in time, and must not be negligent to avoid delaying their condition.