There are a large number of microorganisms in various parts of the normal human body ,such as the skin, mouth, pharynx, vagina and colon, etc. These microorganisms settle, grow and reproduce on the host cells called colonization, and the bacteria that are colonized are called normal strains, and the normal strains play an important role in maintaining the human ecological balance and the stability of the internal environment. Many factors such as host disease, effects of medical interventions, invasion of foreign bacteria and use of antimicrobial agents contribute to:

(1) Imbalance of flora, patients often show diarrhea, colitis, severe cases caused by double infection;

(2) localization transfer, normal flora can be transferred from the original site to other sites to cause infection;

(3) Endogenous infection, also known as autoinfection or opportunistic infection.

These problems are common when the host immune function is deficient. The pathogenicity of microorganisms is relative, a pathogen such as a small number can not cause disease; A large number of non-pathogenic bacteria can cause disease. When the pathogenic microorganism causes infection, the purpose of cure can be achieved as long as the pathogenic body is destroyed; In the case of endogenous infection caused by normal flora, it is impossible to eliminate the flora, and measures should be taken to adjust the flora.

Normal flora in different parts of the human body:

Skin: Staphylococcus, diphtherioid Bacillus, Pseudomonas aeruginosa, propionibacterium situs, anaerobic G+ coccus, penicillium, etc.

Intestinal tract (endjejunum, ileum, colon) : Escherichia coli, Aerobacter, Proteus, Pyobacter aeruginosa, Staphylococcus, Sarcina, Enterococcus, Bacillus perfringens, Bacillus, Bifidobacterium, Eubacillus, Prismoides, Peptococcus, Peptostreptococcus, Candida albicans, Eko-virus, adenovirus, etc.

Anterior urethra: surface staphylococcus, non-pathogenic acid-fast Bacillus, Enterococcus genus.

Vaginal: Lactobacillus, diphtherioid bacillus, Escherichia coli, Bacillus, Enterococcus, Neisseria, anaerobic coccus, etc.

Each infection has a specific pathogenic microbe called a pathogen. The common pathogenic bacteria of urinary genital infection in clinic include: Staphylococcus aureus, hemolytic streptococcus, gonococcus, Pseudomonas (Pseudomonas aeruginosa, etc.), diphtheria, Escherichia coli, tuberculosis bacillus, mycoplasma, Chlamydia, various viruses, various fungi, trichomonas, etc.