![Antonius Van Leeuwenhoek - (1676) (A Dutch
[draper] merchant who lived from 1632-1723)
• He was the first to invent a primitive microscope. It consisted of a
single magnifying lens held in a flame but he was able to see objects
which he called animalcules in rain water from pools, scrapings
(tartar) from teeth and in faeces.](https://image.slidesharecdn.com/lecturetwointroductiontomicrobiology-230523094318-67f266e0/85/LECTURE-TWO-Introduction-to-microbiology-pptx-17-320.jpg)
LECTURE TWO Introduction to microbiology.pptx
- 1. Introduction to microbiology Kabombo joe ( Bsc P.H,EN,M.C cert. M&E,P.M,L.M)
- 2. introduction • Microbiology comprises and integrates the fields of immunology, bacteriology, virology, mycology and parasitology, each of which has seen considerable independent development. The common bond between all these courses under microbiology is the focus on the causes of infectious diseases and on the reaction of the body or the host to the pathogens. • The objective of this course is to instill a broad base knowledge of the etiological microorganism that cause disease; how the body responds to this invasion by pathogenic microorganism and be able to prevent disease in your working environment. This knowledge is a necessary prerequisite for the diagnosis, treatment and prevention of infectious diseases.
- 3. Definition of terminologies used in microbiology • MICRO-------------: Small or minute • BIO----------------- Life • LOGY-------------- Study • From the meaning of these three words, we can see that microbiology is the study of small living organisms. It can also be defined as the scientific study of minute living organisms which include bacteria, viruses, fungi and yeasts.
- 4. • Microbiology: This is the scientific study of minute living organisms which include bacteria, viruses, fungi and yeasts. Microbiology is also a science that studies micro-organisms and their effects on humans and animals. • Micro- organism (microbe): A microscopic cell or a very small living organism. • Microscopic: This term refers to organisms that are extremely small, visible only with the aid of a microscope.
- 5. • Dark ground microscopy: This is a method of microscopy which allows unstained microorganisms to be seen. • Pathology: This is the branch of medical science that studies the causes, nature and effects of diseases. • Pathogenic: A disease causing organism. • Infection: The successful invasion and multiplication of pathogenic organisms either on the body surface or in the body systems.
- 6. • Pathogen: A pathogen is a microbe that has the ability to cause host tissue injury. The host damage can be as a result of direct microbial activity or arise from the host immune response. This definition encompasses classical pathogens and opportunistic pathogens. • Pathogenesis: Pathogenesis is the mechanism involved in the development of a disease. • Pathogenicity: Pathogenicity is the ability of an organism to cause disease. • Virulence: This is defined as the level or degree of pathogenicity. Thus, a pathogen has greater virulence if its capacity to cause host damage is high.
- 7. • Parasite: This is an organism living upon or within another living organism deriving benefits as well as causing harm to the host. The term also can refer to an animal or plant or microorganism which depends on another living animal or plant to provide some or all necessities for its life process. • Ecto parasite: This term refers to a parasite which lives on the surface of its host e.g. a flea or lice. • Endo parasite: This term refers to a parasite which lives inside its host e.g. malaria parasite or worms. • Bacteriology: This is a branch of microbiology which deals with the scientific study of bacteria or branch of medical science that studies bacteria in relation to disease.
- 8. • Virology: Virology is a branch of microbiology which deals with the scientific study of viruses or branch of medical science that studies viruses and viral diseases. • Mycology: This is a branch of microbiology which is concerned with the scientific study of fungi or branch of botany that studies fungi and fungus- causing diseases. • Protozoology: The branch of microbiology concerned with the scientific study of protozoa. • Haematology: The science dealing with the formation, composition, functions and diseases of the blood. The branch of science concerned with the study of blood, blood-forming tissues and the disorders associated with them
- 9. • Oncology: The branch of medicine that deals with the scientific study of tumours. • Attenuated strain: A strain of micro-organism which has diminished virulence or which is weakened. • Autoclave: A device in which objects are sterilized by steam under pressure. • Carrier: A person who, though not suffering obviously from a particular disease, continues to harbor and to excrete the causative organisms which may be passed on to others. • Chemotherapeutic agent:This term refers to a synthetic substance which has a destructive action against microorganisms and which is used to treat infection.
- 10. • Fermentation: This term refers to the incomplete splitting of sugar by microorganisms to provide energy for their growth which yields alcohol, acids and gases. • Genus: This term refers to a group of animals or plants which though not identical, have • many characteristics in common. • Gram stain: This term refers to a method of bacteriological staining which divides bacteria into gram-positive and gram-negative types. The gram reaction depends on the nature of the bacteria cell wall. • Host: The animal or tissue on which a parasite lives and multiplies. • Interferon: A substance released by cells infected with viruses which renders other cells resistant to viral infection
- 11. • Infection: A state in which the body or part of it is invaded by a pathogenic organism which under favourable conditions, multiplies and produces effects which are harmful or injurious to the host cells. • Macrophage: A large white blood cell which has the ability to ingest (phagocytose) bacteria and other particles found in chronic inflammation. Antibody A specific substance (a type of protein produced by plasma cells) found in the blood that is formed in response to an antigen. • Antigen: A substance that stimulates the production of antibody or reacts with them when introduced in the body. • Antitoxin: An antibody which can specifically neutralize a particular toxin.
- 12. • Toxin: Poisonous substance released by certain organisms which has damaging action on the tissues • Asepsis: Free from germs or from infection • Antiseptic: It is a chemical agent which prevents the growth of micro-organisms, particularly on body surfaces and endothelial linings. • Bacteriocide: It is an agent that kills/destroys bacteria. • Acid fast bacillus: It is an organism which when stained will resist decolorization by acids. e.g Mycobacterium tuberculosis • Aerobe (aerobic organism): It is a micro-organism which can only live or thrive (grow) in the presence of oxygen. • Anaerobe (anaerobic organism): It is a microorganism which can only live or thrive in the absence of oxygen
- 13. • Facultative anaerobe: It is a microorganism which can grow under both anaerobic and aerobic conditions. • Commensals (normal flora):These are harmless organisms in their normal sites but capable of causing disease when transmitted to an abnormal site e.g. Escherichia coli (Escoli) are the harmless resident of the gut which can cause infection in the wound or urinary tract. • Medium: The mixture of substances in or on which bacteria are grown or cultivated in the laboratory • Micro aerophilic: Bacteria which grow best in the presence of a low concentration of oxygen i.e. less than that found in the air. • Micron: A unit of measurement of length equals 1/1000th of a millimetre.
- 14. • Motile: Able to move under its own power. • Mutation: The spontaneous, random change which sometimes occurs in the genetic constitution of an organism. • Immunity: The body’s ability to resist invading organisms or to resist infection. Saprophyte: It is a micro-organism which is able to live without parasitizing an animal or plant. • Septicaemia: This is the presence of bacteria and their toxins in the blood stream. • Sepsis: Infection of the body by bacteria or presence of pathogenic micro- organism in the • body.
- 15. • Species: A group of micro—organisms or plants or animals which have common characteristics • Spore: A structure produced by some species of bacteria which is very resistant to adverse conditions e.g. heating or drying which could kill the average bacterium. The spore is also able to survive the adverse conditions and to germinate once conditions are favourable.
- 16. History of Microbiology • Microbiology has had a long, rich history. It initially focused on the causes of infectious diseases but now covers practical applications of the science. Microbiology has developed over a period of years. The notable periods start from 1500 AD to the year 1900 AD to the present time. . The events were happening simultaneously in different countries. Many individuals have made significant contributions to the development of microbiology. The following are the notable ones
- 17. Antonius Van Leeuwenhoek - (1676) (A Dutch [draper] merchant who lived from 1632-1723) • He was the first to invent a primitive microscope. It consisted of a single magnifying lens held in a flame but he was able to see objects which he called animalcules in rain water from pools, scrapings (tartar) from teeth and in faeces.
- 18. • He noted that some were actively moving, and described stick like shapes and spirals after that. The microscope raised a lot of media arguments to the scientists as to whether the animalcules were produced spontaneously (spontaneous generation) which means creation of living from non-living. People believed that mice, maggots and microorganisms arose spontaneously from nowhere. The argument resulted in experiments which often gave conflicting results. Until his death in 1723, van Leeuwenhoek revealed the microscopic world to scientists of the day and is regarded as one of the first to provide accurate descriptions of protozoa, fungi, and bacteria.
- 19. Francesco who lived from 1626-1697. • Through his experiments he discovered that maggots were not spontaneously formed in decomposed meat but that larvae were the maggots which came from the flies.
- 20. Lazzare Spallanzani-1776 • He was an Italian priest and the first person to cultivate bacteria in a sterilized media with and without air. He also demonstrated that heating (boiling) meat for a sufficient length of time and then seal the cooking utensil would not contain bacteria • His experiments excluded air from heated organic materials. By this time, it was becoming clear that air is the common source of microorganism. The theory of spontaneous generation was finally thrown out and the idea of boiling as a means of sterilization was generally accepted.
- 21. Edward Jenner- 1798 • He introduced the cowpox vaccine/vaccination
- 22. Fracastoro (An Italian physician)-1546 • He first suggested that infection is the same for who received and who has given the infection (like other known living things animalcules arose from others like them). • Infection is caused by minute insensible particles and is spread by means of them. He also introduced the idea of contagium vivum.
- 23. Semmelewes-1847 • A Viennese obstetrician, he noted that puerperal fever was transmitted from one patient to another through hands of attendants. He showed that infection could be reduced by hand washing in between patients using chlorinated lime as an antiseptic. This discovery made the foundation stone of modern antiseptic techniques being used in hospitals.
- 24. John Snow-1854 • John Snow was a scientist in London who demonstrated that cholera was transmitted through drinking contaminated water.
- 25. Loius Pasteur- (1822-1895) • Pasteur was a French chemist from France who demonstrated that the microscopic organism called yeast caused the fermentation of sugar and starch into alcohol and that the presence of bacteria was spoiling the wine • He also investigated a silk worm disease which was damaging the silk industry. He developed methods of culture and showed that micro- organisms cause diseases, and this led to the Germ theory of disease. • He further developed vaccines for cholera, anthrax and rabies. He also introduced/invented pasteurization. This is a method of sterilization by heat where milk is heated at a very high temperature and then cooled rapidly.
- 26. Robert Koch- (1843-1910) • He was a German doctor (physician) and his first investigation was into the case of anthrax, (he isolated anthrax bacteria). He developed the bacteriological techniques which form the basis of modern diagnostic bacteriology e.g. use of dyes to colour bacteria and so make them more easily visible under the microscope. • He produced the first satisfactory solid media from blood agar for growth of bacteria. This enabled cultures of a single strain of bacterium to be obtained more readily. He also noted that organisms grew in clusters called colonies which were visible to naked eyes. He discovered the bacterial causes of many diseases including Tuberculosis in 1882 (isolated and described the Tubercle bacilli in 1882-TB/Koch’s disease)
- 27. • He also discovered the substance tuberculin in the colonies of TB bacilli which when injected in the body; it causes antigen-antibody reaction. He defined a system for attributing an organism as the cause of a specific disease. • Koch propounded his famous postulates which are that: a bacterium should always be found in association with its own particular disease • It should be isolated in pure growth from that disease and that; if then given to a suitable animal should reproduce the disease from which it was isolated.
- 28. Klebs and Fredrick Loeffler- (1852-1920) • A German bacteriologist who with Klebs isolated the Diphtheria Bacilli which they named after themselves as Klebs Loeffler Bacilli (KLB) • In 1888, they discovered that symptoms of diphtheria were not caused directly by bacteria but by a substance known as toxin produced by the bacteria, carried in the blood stream and able to produce tissue damage.
- 29. Emil Vanbehring -(1854-1917) • He discovered Diphtheria antitoxin in 1890. He showed that diphtheria could be prevented and cured by the administration of serum from the horse convalescent from diphtheria. This was the discovery of antitoxins.
- 30. Jenner -1749 -1823 • The microbiologist was well known around the world for his innovative contribution to immunisation and ultimate eradication of small pox. This made the foundation for immunology. He discovered vaccination against small pox.
- 31. Theillers-1927 • He was a microbiologist who used chicken eggs to culture the yellow fever virus and won the Nobel Peace Prize in 1951. He discovered the vaccine for yellow fever
- 32. Salk and Sabin • They discovered the vaccine for poliomyelitis. • From the presentation of the scientists who made significant contributions to the study of micro-biology, we note that the progress in the study of microbiology became extremely rapid in the latter part of the 19th century. The following years saw much of the knowledge confirmed. Scientists investigated the detailed structure and physiology of bacteria, the ways in which animals become immune to infectious diseases, and latter it became possible to cultivate and examine viruses.
- 33. • Other advances are the advent and development of substances which kill bacteria in the tissues and so cure many infections, antibiotics and chemotherapy • Antibiotic- is a substance produced by a micro-organism which, in high dilution, kills or inhibits the growth of other micro-organisms.
- 34. • Chemotherapeutical agents - are substances which have similar effect, but which are synthesized or made in the laboratory. Examples of chemotherapeutical agents are sulphonimides. The first was sulphanilamide, the active compound of prontosil shown by Domagk in Germany in 1935. The best known antibiotic, penicillin was discovered by Alexander Fleming in 1929. This was further developed by Florey and Chain in Oxford in 1940. Penicillin is produced by the mould penicillium notatum. It was called the magicalbullet which cured anything at that time.
- 35. Other Microbiologists • KIYOSHI SHIGA- (1870-1959) • He discovered the dysentery bacilli known as shingella shiga • Albert Neisser- (1855-1916) • He discovered the gonococco organism which causes Gonorrhoea, It was named after him and called it Neisseria Gonorrhoea • Edward Klein- (1844-1925) • He identified streptococcus as the cause of scarlet fever.
- 36. • Angus Von Wasserman- (1866-1925) • He introduced the first use for diagnosis of syphilis which is known as Wassermann’s Reaction • Leon Calmette - (1863-1933) • Together with Camille Guren, they introduced a BCG vaccine (Bacillus Camille Guren) against tuberculosis. • William Welchi- (1850-1935) • He discovered and described the organism that causes GAS GANGRENE as Clostridium Welchi
- 37. • Sir William Alexander Flemming -(1891 1955) • A British bacteriologist who in 1929 discovered the antibiotic penicillin • Prince Charles Chamberland- (1857-1908) • He discovered an instrument called an Autoclave used in the sterilization of surgical instruments
- 38. Prepared by: KABOMBO JOE THANK U ALL