Clinical Microbiology and Infectious Diseases

Pathogenicity of Microbes

Pathogenicity refers to the ability of an organism to cause disease (i.e. harm the host). This ability represents a genetic component of the pathogen and the overt damage done to the host is a property of the host-pathogen interactions. Commensals and opportunistic pathogens lack this inherent ability to cause disease. However, disease is not an inevitable outcome of the host-pathogen interaction and, furthermore, pathogens can express a wide range of virulence. Virulence, a term often used interchangeably with pathogenicity, refers to the degree of pathology caused by the organism. The extent of the virulence is usually correlated with the ability of the pathogen to multiply within the host and may be affected by other factors. The development of a disease state is a dynamic process that is dependent on the virulence of the pathogen and the resistance of the host. It covers biology, host-pathogen interaction and medicine associated with infectious agents, as well as microorganism, fungi, viruses and protozoa. Microbic pathological process is committed to the study of the genomic, molecular and cellular bases of clinical infectious diseases.