What are bacterial diseases | Type and Cause

Bacterial disease is an infectious or infectious disease caused by bacteria. There are two main classifications of bacteria. One is the phenotypic classification method, which is based on the phenotypes of bacteria, biochemical reactions, and serum reactions. The other is classification using nucleic acid research, that is, by analyzing the base composition of the bacterial DNA, the size of the genome, and the homology of the DNA. The latter classification is very scientific, so that some bacteria re-assign or replace the name.

 

In the normal human body surface and the cavity that communicates with the outside world, such as the oral cavity, nasopharyngeal, intestinal tract, reproductive tract, etc., there are various microorganisms, which are beneficial to the human body under normal conditions of human immune function, and are called normal. Flora. Among them, living on the human body surface are: Staphylococcus aureus, Staphylococcus aureus, Corynebacterium sp. JK, and Propionibacterium acnes. Living in the oropharynx are: Staphylococcus, alpha and beta hemolytic streptococci, non-hemolytic streptococcus, pneumococcus, Neisseria, Moraxa, Haemophilus, Anaerobacter, Lactic acid Bacillus, diphtheria-like bacilli, Eubacterium, Fusobacterium, Bacteroides, Candida albicans and so on. Those who colonize the intestines (end of jejunum to colon) are E. coli, Enterobacter aerogenes, Proteus, Pseudomonas, Staphylococcus, Enterococcus, Clostridium perfringens, Peptococcus, Peptostreptococcus, Bacillus (mainly Bacteroides fragilis), Bifidobacterium, Eubacterium, Fusobacterium, Candida albicans and the like. Bacteria living in the vagina include: Lactobacilli, Diphtheroids, Bacteroides, Enterococcus, Escherichia coli, Neisseria, Anaerobic cocci.

 

When the body's resistance is reduced, or when defense immune function is reduced due to various reasons (such as aging, diabetes, cirrhosis, cancer, hematology, chemotherapy, radiotherapy, immunosuppressive agents, hormones, and antibacterial drugs, etc.), it is normal. Germ bacteria or bacteria with low pathogenicity may invade other parts of the body and cause infections, which are called opportunistic pathogens (conditional pathogens). These conditional pathogens may be human normal flora, or present in the environment and usually not pathogenic, such as E. coli, K. pneumoniae, P. aeruginosa, Enterobacter, Serratia, Salmonella in Enterobacteriaceae bacteria Genera, Staphylococcus aureus, Staphylococcus aureus, Enterococcus, Clostridium perfringens, Listeria genus, Nocardia star, etc.; Candida, Aspergillus, Cryptococcus neoformans, Mucor and other fungi . In addition, it may be caused by certain viruses or protozoa.