微生物学是对微观生命形式（例如细菌和病毒）以及对这些微生物的免疫反应的研究。使用遗传学，化学，生物化学，生理学，生态学和病理学的技术来研究微生物的生物学是一个广泛的，多学科的领域，从分子水平上的基因表达到微生物种群的组成。涉及微生物的令人兴奋的发现对生物技术，分子生物学，医学，公共卫生和环境具有重要而深远的影响。艾滋病和其他重要疾病给公共卫生领域的微生物学家带来了新的令人振奋的挑战，重组DNA技术，免疫学以及操纵微生物细胞生物学的能力的进步彻底改变了科学，并将微生物学推向了迅速发展的中心生物技术领域。
Microbiology is the study of microscopic forms of life such as bacteria and viruses and the immune response to these microorganisms. It is a broad, multi-disciplinary field using techniques of genetics, chemistry, biochemistry, physiology, ecology, and pathology to study the biology of microorganisms from gene expression at the molecular level to the composition of populations of microorganisms. Exciting discoveries involving microorganisms have important and far reaching implications for biotechnology, molecular biology, medicine, public health and the environment. AIDS and other important diseases present new and exciting challenges for microbiologists in the public health field, and advances in recombinant DNA technology, immunology, and the ability to manipulate the biology of microbial cells have revolutionized science and thrust microbiology into the center of the rapidly expanding arena of biotechnology.