History and Scope of Microbiology. MDCN241 Medical Microbiology

Transcription

1 History and Scope of Microbiology MDCN241 Medical Microbiology

2 At the end of this lesson the student should be able to List the landmark contributions in the history of microbiology List the main contents of microbiology List the main references in microbiology List the differences between prokaryote and eukaryote Classify the microorganisms

3 The Science of Microbiology

4 To learn microbiology You need: Fundemental background in biology Some knowledge of chemistry

5 Microbiology will provide you With a general background knowledge of microorganisms Relationship of these microorganisms to one another and To other organisms

6 You will learn Basic principles Application of them in modern science

7 Rapid developments Knowledge should be updated

8 Emerging pathogens Expanding problem of drug resistant microbes

9 New understanding themes in evolution and biodiversity

10 History has contributed to contemporary applications

11 Noted biologist and writer Lewis Thomas Nature abounds with little round thinks

12 Anton van Leeuwenhoek Three centuries ago First described in detail These little round things Became the most studied living organisms Not all are around nor are all friendly Some cause the most serious and devastating diseases known to humans Yet we could not live without these microscopic forms

13 The principles and applications of microbiology Are integral part of such areas as Medicine Genetics Biochemistry Molecular biology Ecology Agriculture Biotechnology

14 Imagine a world Life-threatening diseases are dignosed in minutes using molecular techniques to identify the pathogen Picture a society in which highly specific antibodies are used as magic bullets to target drugs to cancerous cells and where recombinant DNA in viruses used as vaccines for cancer therapy and to treat certain diseases by gene therapy

15 Superbugs devour toxic pollutants, clean up oil spills and eliminate agricultural pests without harm to animals,humans and plants Genetically engineered bacteria fertilize crops and significantly increase agricultural production Plants genetically moodified to protect them from insects, drougt and disease

16 The world described in this scenario is not in future It exists today Microorganis are used as small factories producing any biochemical a person desires These minute organisms provide scientists with the capability of un derstanding in greater detail the genetic composition of all forms of life.

17 microbes Play indispensible roles in our daily lives They are important not only in molecular biology, biotechnology but also in medicine, ecology,agriculture and industry. This knowledge did not emerge overnight but resulted from about a century of careful and deliberate scientific advances in the field of microbiology.

18 Microbology As a science began with the development of the microscope Inventor?

19 Microbiology Young discipline Dynamic science With new information constantly displacing old theories and assumptions. This makes microbiology an exciting science

20 From Louis Pasteur s Simple but ingenious experiments in the 19th century To disprove the doctrine of spontaneous generation To contemporary discoveries in recombinant DNA technology Microbiologists have been in the forefront of science

21 With this introductory lesson We will begin our journey through the field of Microbiology!!!!

22 Medical Microbiology Patrick R Murray Ken S Rosenthal Michael A Pfaller

23 To all who use this text book That they may benefit from its use As much as we did in its preparation

24 In Microbiology We will discover what microorganisms are Why we should study them.

25 History of Microbiology We will also take a little time to place the science of microbiology in historical perspective Highlighting some of the landmark contributions of early as well as more recent microbiologists.

26 Microbiology today A dynamic science With ramifications in all aspects of human life including: Medicine Agriculture Environment

27 So Welcome to the study of Medical Microbiology

28 Microorganisms -Creatures that are not directly visible to the unaided eye -They are famous for their biologic diversity

29 Microbiology is the science of microorganisms.

30 Microorganisms Single cells Cell clusters Viruses(microscobic but not cellular)

31 Microbial cells are distinct from Macroorganisms The cells of animals and plants Multicellular Many cells are arranged to form tissues, From these various organs

32 Plants Animals Purple

33 Cyanobacteria The first Oxygen evolving bacteria on Earth Responsible for oxygenating the atmosphere

34 In contrast to macroorganisms Microorganisms are able to carry out Their life processes: -growth -energy generation - reproduction independently of other cells

35 Microorganisms Are everywhere and Affect all other life forms on Earth Thus the science of Microbiology is of enormous importance

36 Microbiology The science of such a large and diverse group of microscobic organisms Basic biological science Applied biological sience

37 Microbiology as a basic biological science All cells have much in common Microorganisms can grow to extremely high densities in laboratory culture Are amenable to biochemical and genetic study Excellent models for understanding cell function in higher organisms

38 So our most sophisticated understanding of Chemical and Physical basis of life have arisen from studies of microorganisms.

39 Microbiology as an applied biological science Medicine: Some of the most important diseases of humans, other animals and plants are caused by microorganisms Agriculture: soil fertility Industry: Many large-scale industrial and biotechnology processes are microbially based: production of antibiotics or human proteins

40 Pharmaceutical microbiology is a new applied branch of microbiology, dealing with microorganisms associated with the production of pharmaceuticals either using microorganisms to manufacture pharmaceuticals or by controlling the microorganisms in the process environment

41 Importance of Microorganisms In the absence of microorganisms higher life forms would never have arisen!: the oxygen is the result of microbial activity Recycling of key nutrients and degrading organic matter by microrganisms They have existed on earth for billions of years before plants and animals appeared.

42 Extent of Microbial life Constitude the major portion of biomass on Earth Total microbial cell number on Earth. 5x10 30 cells Most procaryotic cells do not reside on earth s surface They lie in the ocean and terrestrial subsurfaces

43 Impact of Microorganisms on Humans Microorgansims as Disease agents Microorganisms and agriculture Microorganisms and food Microorganisms, Energy and Environment Microorganisms and Future

44 Microorganisms as diseases agents Microbiologists have a success in controlling the microorganisms by: -understanding the infectious diseases -improvement in sanitary practices and -the discovery and the use of antibiotics.

45 Death rate for the 10 leading causes of death in USA in 1900

46 Death rate for the 10 leading causes of death in USA in 2000

47 We now live in a world Many pathogenic microorganisms are in control Microorganisms are still a major threat such as in - AIDS patients -the cancer patients with devastated immune system -in patients with a multiple drug resistant pathogen

48 Microbial diseases still constitude Major causes of death in many developing countries of the world. Eradication of smallpox is a great success But millions still die yearly from -malaria, -tuberculosis, -cholera, -African sleeping sickness and -severe diarrheal syndromes

49 As the years, centuries pass While wondrous discoveries are being made New pathogens and their disease, Old pathogens causing new diseases and Increased threat of biologic terrorism are also discovered: -Smallpox -Anthrax -Brucellosis

50 Clearly microorganisms are still serious threats to human existance but Most are not harmful to humans They are actually beneficial

51 Like any science Modern microbiology owes much to the past. Despite the early roots the science of microbiology did not really develop until the nineteeth century.

52 The historical roots of microbiology Robert Hoooke (1664) Fruiting structures of molds

53 Hooke s microscope Hooke s microscope Hooke s microscope

54 A drawing by Hooke of blue molds which represents one of the first descriptions of microorganisms

55 Antoni von Leeuwenhoek The first person to see microorganisms in detail by microscope in 1684 and to report them A dutch amateur microscope builder

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58 But Understanding the nature and importance of these tiny organisms came only slowly.

59 Only in the 19th century Improved microscobes became available

60 Ferdinand Cohn Was the founder of bacteriology Discovered bacterial endospores Heat resistant forms of bacteria He was the first use cotton for closing flasks and tubes to prevent the contamination of sterile culture media

61 Downfall of spontaneous generation 19th century Louis Pasteur Swan-necked flask Microorganisms arose spontaneously from nonliving materials- spontaneous generation

62 Sterilizing the contents of the flask

63 If the flask remained upright, no microbial growth occured

64 If microorganisms trapped in the neck reached the sterile liquid, microbial growth ensued

65 Sterilization Killing all the bacteria or other microorganisms in or on objects This procedure used by Pasteur, Cohn and other were refined.

66 Pasteur Developed vaccines for Anthrax Rabies Fowl cholera

67 Koch Was the first to grow bacteria on solid culture media (gelatin) He was the first to grow pure culture of bacteria Koch s postulates: the link of a spesific microrganism to a spesific disease.

68 Taking bacteria from liquid culture

69 Inoculating on a solidified media

70 Isolated colonies of bacteria (pure culture) The media was solidified first by gelatin then By agar : a polysaccaride from red algae

71 Koch s postulates The suspected pathogenic organism should be present in all cases of the disease And absent from healthy animals

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73 Koch s postulates The suspected organism should grow in pure culture

74 Koch s postulates Cells from a pure culture of the suspected organism should cause disease in a healthy animal

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76 Koch s postulates The organism should be reisolated and shown to be the same as the original

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78 Koch s postulates not applicable to all microrganisms Viruses Chlamydia trachomatis Rickettsia rikkettsii Treponema pallidum

79 Koch s postulates for the 21st century More recently, modern nucleic acid-based microbial detection methods have made Koch s original postulates even less relevant. These nucleic acid-based methods make it possible to identify microbes that are associated with a disease, but in many cases the microbes are uncultivable. Also, nucleic acid-based detection methods are very sensitive, and they can often detect the very low levels of viruses that are found in healthy people without disease.

80 The use of these new methods has led to revised versions of Koch s postulates Fredricks and Relman have suggested the following set of Koch s postulates for the 21st century.

81 Koch s postulates for the 21st century by Fredricks and Relman A nucleic acid sequence belonging to a putative pathogen should be present in most cases of an infectious disease. Microbial nucleic acids should be found preferentially in those organs or gross anatomic sites known to be diseased, and not in those organs that lack pathology...

82 Robert Koch Discovered the cause of tuberculosis (one-seventh of all reported human deaths were caused by tuberculosis) Was awarded the 1905 Nobel prize for physiology of medicine.

83 Beijerinck Developed enrichment culture for selecting spesific microorganisms isolated many soil and aquatic microorganisms Tobacco mosaic disease ( filtered agent other than bacteria-virus concept)

84 Almost 100 years after Leeuwenhoek Otto Müller Organized bacteria into genera and species according to the classification methods of Linnaeus Taxonomic classification of microbes

85 The era of chemotherapy Paul Erlich (1910): First antibacterial agent Alexander Flemming (1928): Penicillin

86 Virus culture in cells 1946 John Enders Large-scale production of virus cultures for vaccine development

87 20th century Applied microbiology: Medical microbiology and ımmunology Basic microbiology

88 Around 1950 Bacterial genetics became a major field of study.

89 By the early 1960s An advanced understanding of DNA, RNA and protein synthesis Caused the arise of Molecular Biology

90 In the middle and to later part of the twentieth century Basic and applied microbiology worked hand in hand to usher in the current of molecular microbiology

91 In the new millenium Entire genomes can entirely be sequenced It is easy to see that the science of microbiology has come a long way in 300 years. But the best is yet to come!!!!

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93 The tools required for the analysis of microorganisms are provided by: Biochemistry Molecular biology genetics

94 Cell Eukartotes: -membrane bound nucleus -relatively large size -presence of membrane bound organelles (such as mitochondria) Prokaryotes: DNA is not physically separated from the cytoplasm

95 Eukaryotes and prokaryotes: Are organisms -with all the enzymes required for their replication and -biologic equipment necessary for the production of metabolic energy They are different from viruses which depend on host cells for these functions

96 Typical eucaryotic cell

97 The three phylogenetic lineages of cells (Domains according to comparative rrna sequences) Bacteria Archae Eukarya

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99 Bacteria :Prokaryotic Archae :Prokaryotic Eukarya :Eucaryotic

100 Major subdivisions: -algae, -protozoa -fungi -slime molds Microbial eukaryotes (protists)

101 Viruses unique properties Different from living creatures They depend on a host for replication A viral particle: a nucleic acid molecule (either DNA or RNA) enclosed in a protein coat or capsit

102 Virus Poison (latin) Iwonowsky Beijerinck

103 Viroids Small single stranded Circular RNA molecules Transmissible plant diseases

104 Prions Cause of degenerative central nervous system disease No nucleic acid Infectious protein Resistant to sterilization

105 Medical Microbiology Bacteria Viruses Fungi Parasites Prions

106 Diagnostic Microbiology Clinical Microbiology Laboratory: -Diagnosis -Control of Infectious Diseases

107 The success of the Microbiology laboratory Quality of the specimen The way its sent The method used The interpretation

108 Viruses The smallest infectious particles nm (ranging in diameter nm) Particles less than 200nm can not be seen by light microscope More than 40 genera implicated in human disease

109 Viruses True parasites Require host cell for replication Infection lead to rapid raplication and cell destruction or Longterm latent relationship HIV...AIDS

110 Bacteria Relatively simple cell Prokaryotic Cell wall: gram-negative or positive

111 Bacteria Preliminary classification: -size (1-20 micrometer) -shape(phere,rod,spiral) -arrangement (single cell, chain, cluster)

112 Bacteria Phenotypic Genotypic properties form the basis for definitive classification.

113 Fungi Eukaryotic More complex Yeasts Molds

114 Parasites The most complex Eukaryotic Unicellular, multicellular Size (variable: 1-2 micrometer:certain protozoa to 10m) Complex life cycle

115 Emerging and reemerging microorganisms HIV Crimean-Congo haemorrhagic fever West Nile virus Influenza(Avian flue, Pandemic flue) Sars (SARS-CoV) EBOLA MERS-CoV.....

116 Reference websites Who Cdc, ecdc saglik.gov.tr, Society websites ( klimik.org,

117 Scope of Pharmaceutical involves four main areas: Microbiology -Sterility of the pharmaceutical product -Anti-infective agents -Investigation of mutagenic and carsinogenic activity in prospective drugs by using microorganisms -Use of microorganisms as small microscopic factories for manufacturing pharmaceutical products.