Special stains for microorganisms
For there to be an infection, it is necessary on the one hand an infectious agent and on the other hand that this infectious agent has a harmful interaction for the host. Any interaction between an infectious agent and a host does not lead to an infection because in the vast majority of cases it creates a balance between the forces involved and this balance results in colonization of the host by different germs, this without infection.
For there to be an infection, there must be a break in this balance.
There are different infectious agents (microbes or micro-organisms) classified in different categories (families). The main categories are:
Not all microorganisms (germs) have the same ability to cause infections, some are almost always associated with clinical manifestations, while others only provoke them exceptionally.
There are special stains in histology to visualize the different families of infectious agents to establish a diagnosis of infectious disease.