Introduction to Microbiology PDF Lecture Notes

Lecture No. -1 INTRODUCTION TO MEDICAL MICROBIOLOGY INTRODUCTION: Microbiology defined as the study of organisms too small to be seen with the naked eye. Microbes or microorganisms are microscopic living things that are usually unable to be viewed with the naked eye. They include Bacteria, fungi,...

Lecture No. -1 INTRODUCTION TO MEDICAL MICROBIOLOGY INTRODUCTION: Microbiology defined as the study of organisms too small to be seen with the naked eye. Microbes or microorganisms are microscopic living things that are usually unable to be viewed with the naked eye. They include Bacteria, fungi, protozoa, algae and viruses. Some microbes are pathogenic and many microbes are beneficial. HISTORY OF MICROBIOLOGY: The German scientist “Antoni van Leeuwenhoek 1673-1723” is the father of microbiology because he is the first person described live microorganisms that he observed in teeth scrapings and rain water. He gives the name “animalcules” for these microorganisms. The French scientist Louis Pasteur (1822–1895) developed a process (today known as pasteurization) to kill microbes. Pasteurization performed by heating liquids to 63 to 65 C for 30 minutes or to 73 to 75 C for 15 seconds. Robert Koch (1843–1910): was a pioneer in medical microbiology and worked in cholera, anthrax and tuberculosis. He was awarded a Nobel prize in 1905 for the work (Koch's postulates) in which he set out criteria to test microbes as a cause of the disease. Carolus Linnaeus (1735) established the system of scientific nomenclature. GENERAL CONCEPTS: Microorganisms are organisms that are too small to be seen with the unaided eye. “Germ” refers to a rapidly growing cell. There are large types of microbes in the world and more than 90% of the cells in our body are Microbes. Some microbes have Prokaryotic cells and some have Eukaryotic cells. ▪ B- Human Pathogens [A] Subcellular Infectious Entities (Acellular microbes): Acellular microbes: They are not composed of cells and they are smaller than cells. The acellular microbes considered by most scientists to be non-living entities. 1- Prions (proteinaceous infectious particles). They are protein molecules that cause degenerative central nervous system (CNS) diseases such as bovine spongiform encephalopathy (BSE). 2- Viruses. Ultramicroscopic, obligate intracellular organelles that: ▪ — contain only one type of nucleic acid, either DNA or RNA, ▪ — possess no enzymatic energy-producing system and no protein-synthesizing apparatus, ▪ — force infected host cells to synthesize virus particles. [B] Prokaryotic and Eukaryotic Microorganisms (Cellular microbes): Cellular microbes: are composed of cells and considered living organisms. They are usually referred to as microorganisms. ▪ Pathogenic microorganisms are found in the domains bacteria and eucarya. Pathogenic eukaryotic microorganisms include fungal and protozoan species. Microbes Cellular Infectious Acellular microorganisms infectious agent Prokaryote Eukaryote Archea 1- Fungi 1- Viruses 2- Algae Bacteria 3- Protozoa 2-Prions