BACTERIA AS A DISEASE CASUATIVE AGENT

Any microorganism live and multiply inside human body are called parasite. The body which the parasite lives is called host, in this case; the body is harboring the parasite. When the parasite live freely without causing any harm to  the host, they are called co-mensal, why dose parasite that cause harm to their host are called pathogen.

Parasite live in a varieties form, in some case pathogenic parasite may assume co mensal, while co-mensal assume pathogenic form. Some microorganism derived benefit from their host, and also their host drive benefit from them, this form of relationship is called symbiosis, but a situation where by only one partner benefit, and this is called sattelism.

Some of the microorganism prefers dead material for their harboring, such microorganism are called saprophyte. Microorganism cause infection to human being when it penetrate the host body surfaces, and enter the body tissue, multiply, in this state infection has said to have taken place. An infection that causes noticeable impairment of the body is called infectious disease. Disease is a process, and as a result of interaction between the host and the pathogen. In some case the host confer resistance or as susceptibility to the pathogen. Microorganism penetrate the surface of the host such, as skin, mucus membrane, intestinal epithelium these normally act as barrier to them, but many pathway in the first stage by attaching the exact receptor on the surfaces cell and multiply when they are on favorable condition, in these case, they start replication and spreading infection on the epithelium surface before they been release directly to the exterior. The organism the have these ability are diphtheria and streptococcus infection, while some penetrate more deeply into the body by breaking the barrier surface and invade the epithelial tissue in these case the pathogen inhibit body defense mechanism nonviable phagocyte cells and the organ responsible for antibody production. Phagocyte is a very important cell in the body system; they work by engulfing bacteria, Phagocyte secret a molecule cover micro-bicidal molecule so the bacteria which are injected by phagocyte are subjected to this molecule for final decision. The micro-bicidal molecule produce by phagocyte are hydrochloric acid, defensins, superoxide, serpprocidin. These substances kill and crush the bacteria subjected to them. Because of these, some bacteria also have develop of escaping phagocyte killing by possessing a capsules that prevent the microbial molecule to kill them, or they produce some toxic substance called leucocidin these substance kill phagocyte of the host. Some possess a similar substance like that of their host, in this case they cause confusion between the host substance and their pathogen, thereby make it difficult for the body mechanism to recognize them. Once this occurs, they cause excessive damage to the host. The damage cause by this pathogen to the host comes in different reason by involving in toxin production. The toxin produce are of two types base on the environment which they are secreted into; if the toxin produce are secreted to the environment where the organism exist, is called exotoxin. While toxin produce that are secreted into the environment to lysis of the organism this are called endotoxin. The Gram positive bacteria are the one that mainly produce exotoxin, and they are destroy at temperature of 60ºC.

Endotoxin are produce by Gran-Negative bacteria, they are found on their cell wall component, they can with stand up to a temperature of 100ºC the endotoxin are render non-toxic by addition of formalin or by heat temperature above 100ºC if the active of this conversion have no any immunological effect, they can be used to produce active immunity in human and animal against toxin termed toxoid.