INTRODUCTION TO INFECTIOUS DISEASES &HISTORY OF MICROBIOLOGY.pptx

This PowerPoint introduces to infectious diseases and briefy describes the contributions of Nobel laureates in medical microbiology.
it will be useful for MBBS students, BDS, BScMLT, DMLT, and various paramedical students.

1. INTRODUCTION TO INFECTIOUS DISEASES & HISTORY OF MICROBIOLOGY (MI1.1) DR ARUNA RANI BEHERA (MBBS,MD Microbiology) Associate professor Department of Microbiology

2. SPECIFIC LEARNING OBJECTIVES

3. What is Microbiology? Medical Microbiology- Study of microorganisms which produce disease in humans. Branches of clinical microbiology : General microbiology Immunology Hospital infection control Systemic Microbiology

4. Systemic microbiology (infectious diseases) Skin, soft tissue and musculoskeletal system infections CNS infections RTI GI & Hepatobiliary infections Infections of Eye & Ear Blood & CVS infections Urogenital tract infections

5. Extrachromosomal DNA Found in plasmid Found in mitochondria Cell membrane Does not contain sterols except in Mycoplasma Contain sterols Cellular organelles like mitochondria, ER, GA, Lysosomes etc. Absent (except ribosome) Present Ribosome 70S 80S Site of respiration Mesosome Mitochondria CLASSIFICATION OF MICROORGANISMS Characteristics Prokaryotes Eukaryotes Major groups Bacteria, blue green algae Fungi, parasites, plants and Animals, other algae Nucleus Not well defined Well defined Nuclear membrane Absent Present Nucleolus Absent Present Ribonucleoprotein Absent Present Cell division Binary fission Mitosis, meiosis Chromosome One, circular Many, linear

6. Bacteria, blue green algae Fungi, parasites, other algae, plants and animals Diffuse Well defined Doesn’t contain sterols Contain sterols

7. HISTORY OF MICROBIOLOGY A V Leeuwenhoek Paul Ehrlich Louis Pasteur Robert Koch

8. Proposed Principles of F ermentation Disproved theory of S pontaneous generation of disease . S terilisation techniques- steam steriliser , hot-air oven & autoclave Method of P asteurisation of milk Liquid Media concept Developed vaccines for Cholera, Anthrax & Rabies (CAR) Father of Microbiology Postulated G erm theory of disease Founder of Pasteur Institute Paris Coined the term Vaccine

9. Introduced solid media for culture of bacteria Introduced methods for isolation of bacteria in pure culture Described hanging drop method for testing Motility Discovered anthrax bacilli , tubercle bacilli and cholerae bacilli Developed staining techniques using Aniline dye. Koch’s postulates ROBERT KOCH

10. 1) The microorganism should be constantly associated with the lesions 2) It Should be possible to isolate the organism in pure culture from the lesion of the disease. 3) Inoculation of pure culture should produce similar lesions in experimental animal. 4) It should be possible to re-isolate the bacteria in pure culture from lesions produced in experimental animals Additional criterion: It should be possible to demonstrate specific antibodies to the microbe KOCH’S POSTULATES

11. Exceptions to Koch’s postulates: There are some bacteria that do not satisfy one or more of the four criteria of Koch’s postulates. Those organisms are: No animal model Mycobacterium leprae Treponema pallidum

12. 1. Virulence factor or its product should be found in pathogenic strains of the organism. 2. Mutating the virulence gene to disrupt its function should reduce the virulence of the pathogen 3. Reversion of a mutated virulence gene should restore virulence to the strain 3 MOLECULAR KOCH’S POSTULATES He stated that gene(coding for virulence) of a microorganism should satisfy all the criteria of Koch’s postulates rather than the microorganism itself. Mutation Modification of Koch’s postulates by Stanley Falkow .

13. HISTORY F irst observed microorganisms using ground lenses D iscovered that puerperal sepsis is contagious and introduced the concept of antisepsis . Invent ed the smallpox vaccine Antonie van Leeuwenhoek Edward Jenner Ignaz Semmelweis

14. THANK YOU Father of Antiseptic surgery He observed that postoperative infections were greatly reduced by using carbolic acid during surgery to sterilize the instruments and to clean the wounds. Father of Chemotherapy first to report acid-fast nature of tubercle bacillus Developed techniques to stain tissues and blood cells proposed a toxin-antitoxin interaction called Ehrlich phenomenon proposed the ‘side chain theory for antibody production’ discovered salvarsan (‘magic bullet’) as the first effective medicinal treatment for syphilis bacteria ‘ Ehrlichia ’ was named after him founder of Paul Ehrlich Institute , Germany JOSEPH LISTER PAUL EHRILICH

15. NOTABLE MILESTONES IN MICROBIOLOGY

16. ANTIBIOTIC ERA Development of various antibiotics and vaccines followed (dawn of antibiotic era ) Smallpox was eradicated globally (1980) Antibiotic resistance developed soon and has emerged as a global emergency Discovered penicillin (1928)

17. EPIDEMICS AND PANDEMICS 1300s: Black death (plague) in Europe and Asia 1918: Spanish flu (H1N1 virus) )

18. Microorganisms named after discoverer 18 Discoverer Organism Hansen Mycobacterium leprae Yersin & Kitasato Yersinia pestis Schaudinn & Hoffman Treponema pallidum d’Herelle Bacteriophages W.H. Welch Clostridium perfringens Anthony Epstein and Yvonne Barr Epstein-Barr virus Common name Scientific name Kleb-Loeffler bacillus Corynebacterium diphtheriae Koch Week bacillus Haemophilus aegyptius Pfeiffer’s bacillus Haemophilus influenzae Whitmore bacillus Burkholderia pseudomallei Battey bacillus Mycobacterium intracellulare Eaton’s agent Mycoplasma pneumoniae Gaffky Eberth bacillus Salmonella Typhi

19. MOLECULAR MICROBIOLOGY Major discoveries W Gilbert and F Sanger — Sequencing of DNA (1977) Kary Mullis — Polymerase chain reaction (1983) H. influenzae — 1st microbial whole genome sequence (1995)

20. CLASSIFICATION, NOMENCLATURE AND TAXONOMY OF BACTERIA Easy i dentification of microbes Carolus Linnaeus introduced a classification system consisting of kingdom, phylum, class, order, family, genus and species Clone — derived from a single cell; almost all are identical Colony — represents one clone Strain — derived from a single source Kingdom → Division → Class → Order → Family → Tribe → Genus → Species

21. BACTERIAL TAXONOMY 1) Phylogenetic Represented as a branching tree One characteristic—for division at each branch or level Based on ribosomal RNA 2) Adansonian classification/ Numerical taxonomy All characteristics are taken into account Several characteristics are compared at same time 3) Molecular or genetic classification Degree of genetic relatedness Based on the genes, DNA relatedness A:T & G:C ratio :Constant within the same species Used for classifying viruses 4) Intraspecies classification Diagnostic and epidemiological purpose Classified as: Biotypes: Biochemical properties Serotypes: Antigenic features Phage types: Bacteriophage susceptibility Colicin types: Production of bacteriocins

22. MOLECULAR EPIDEMIOLOGY & TYPE CULTURES Phenotypic - Study of expressed characteristics Genotypic- direct analysis of genes, chromosomal DNA & Extra chromosomal DNA. Contain representatives of all species Maintained by International Reference Labs Made available for study and comparison ATCC (American Type Culture Collection) NCTC (National Collection of Type Cultures)

23. HIV HEPATITIS A,B,C,D,E COVID-19 HERPES VIRUS DENGUE, CHICKUNGUNYA INFLUENZA MEASLES HPV Candida Cryptococcus Dimorphic fungus Dermatophytes Aspergillus

24. Gram-positive cocci : Staphylococcus, Streptococcus, Pneumococcus, Enterococcus Gram-positive bacilli: Bacillus, Corynebacterium, Actinomycetes, Clostridium Gram-negative cocci : Neisseria, Moraxella Gram-negative bacilli : Enterobacterales , vibrio, non-fermenters GRAM STAIN

25. Short Notes: Contributions of Louis Pasteur to Microbiology. Koch’s postulates. Who has described the germ theory of life? a. Antonie van Leeuwenhoek b. Louis Pasteur c. Robert Koch d. Paul Ehrlich 2. Who has introduced the sterilization techniques? a. Louis Pasteur b. Edward Jenner c. Robert Koch d. Paul Ehrlich 3. Who is known as ‘father of chemotherapy’? Joseph Lister Robert Koch Alexander Fleming Paul Ehrlich 4. All of the following are Koch’s postulates EXCEPT: The bacterium should be constantly associated with the lesions of the disease caused by it It should be possible to isolate the bacterium in pure culture from the lesions Inoculation of such pure cultures into suitable laboratory animals should reproduce the disease The bacterium need not be re-isolated from lesions produced in experimental animals

26. Which organisms does not follow Koch’s postulates? Stanley B. Prusiner was awarded the Nobel prize for his discovery of: The first scientist to have observed bacteria using a single lens microscope is Who is the father of antiseptic surgery? The smallpox vaccine was discovered by: Who is credited with the discovery of the electron microscope? The first whole-genome sequence of a microbe was published in 1995. Which organism’s genome was the first to be published in 1995? Which bacteria was discovered by Robert Koch?