Medical microbiology is a branch of medicine concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease; bacteria, fungi, parasites and viruses.

Whilst epidemiology is the study of the patterns, causes, and effects of health and disease conditions in populations, medical microbiology primarily focuses on the presence and growth of microbial infections in individuals, their effects on the human body and the methods of treating those infections.