SOME IMPORTANT DEFINATIONS RELATING TO ANTIBIOTICS

PATHOGENESIS:

A microorganism is called a pathogen if it is a capable of causing a disease. Some organisms are frequently pathogens whereas other cause disease rarely.

OPPORTUNISTIC:

Opportunistic bacteria are those, which rarely if ever cause disease in immuno-competent individuals but can cause serious disease in immuno-compromised people (whose defense mechanism are reduced).

VIRULENCE:

Virulence is quantitative measure of pathogenicity.

LD:

50% lethal dose is the number of organism needed to kill the half of the host.

ID:

50% infectious dose is the number of organism needed to cause infection in half of the host.

EPIDEMIC:

An infection is epidemic if it occurs much more frequently than usual.

PANDEMIC:

If a disease has worldwide distribution it is known as pandemic.

ENDEMIC:

An endemic infection is constantly present at a low level in a specific population or part of the country or world.