MICR 201 Microbiology for Health Related Sciences

1. Lecture 1: The Microbial World Edith Porter, M.D. MICR 201 Microbiology for Health Related Sciences

2. Lecture Outline • Definition of Microbiology • Size dimensions • Classification of microbial agents • Microbial diversity • Role of microbes in nature • Beneficial • Environment • Normal microbiota • Commercial use and industrial applications • Harmful • Disease causing • History of Microbiology

3. What is Microbiology? • Micro • Small (micrometer range) • Not visible with the unaided eye • Bio • Living • Able to reproduce

4. The Dimensions of Microorganisms and Smaller Agents 1 inch 1 cm Human Egg cell (almost 1 mm) 1 mm (1/10 of 1 cm) Erythrocyte (7 mm) 1 mm (1/1000 of 1 mm) Bacterium (2 –4 mm) 1 nm (1/1000 of 1 mm) Large Virus (200 nm)

5. What do We Study in Microbiology? Cell membrane • Cellular organisms • Eukaryotes (have a nucleus) • Prokaryotes (do not have a nucleus) • Acellularagents • Viruses (nucleic acid + protein) • Viroids (nucleic acid) • Prions (protein) Nucleus with genetic material Nuclear membrane Cell membrane Genetic material in cytoplasm

6. Classification of Cellular Organisms (Carl Woese 1978) Protozoa Prokaryotes Domain Archaea Algae Fungi Slime molds Plants Domain Bacteria Animals Helminths Protists Domain Eukarya Eukaryotes

7. The Prokaryotes in Microbiology • Bacteria • Peptidoglycan cell walls • Binary fission • For energy, use organic chemicals, inorganic chemicals, or photosynthesis • Some produce molecular oxygen • Archaea • No peptidoglycan • Often in extreme environments • Diverse metabolic pathways • Not known to cause disease

8. Eukaryotes in Microbiology: Algae • Cellulose cell walls • Use photosynthesis for energy • Produce molecular oxygen and organic compounds

9. Eukaryotes in Microbiology: Fungi • Chitin cell walls • Use organic chemicals for energy • Two forms • Molds • Multicellular • Consisting of masses of mycelia composed of filaments called hyphae • Yeasts • Unicellular • Dimorphic shift

10. The Eukaryotes in Microbiology: Protozoa • Unicellular • Absorb or ingest organic chemicals • May be motile via pseudopods, cilia, or flagella

11. Eukaryotes in Microbiology: Multicellular Animal Parasites • Multicellular animals • Parasitic flatworms and roundworms are called helminths • Microscopic stages in life cycles Dirofilariaimmitis

12. Acellular Microbial Agents: Viruses • Viruses are replicated only when they are in a living host cell • Consist of DNA or RNA core • Core is surrounded by a protein coat • Coat may be enclosed in a lipid envelope (from host cell) • Not all viruses are harmful!

13. Acellular Microbial Agents: Prions • Proteinaceous infectious particles • Consist of protein only • Prions induce conformation changes of normal counter parts • Body’s response leads to symptomatic disease • Neurodegenerative disorders • CJD • BSE Brain section of animal with BSE

14. How do we Name Microbes? • Genus name followed by species name • Typically relate to the discoverer, habitat, properties of the organism or its role • Genus name capitalized, species name lower case • In italic (or underlined)

15. Some Examples for Microbial Name Giving • Escherichia coli or E. coli • Neisseriameningitidisor N. meningitidis Discoverer was Escherich lives in colon space Discoverer was Neisser causes meningitis space

16. Making Scientific Names Familiar

17. The Role of Microbes in Nature:Mostly Beneficial Microbes on human tongue in a healthy individual • Plankton • Geochemical cycling • Microbes recycle carbon, nutrients, sulfur, and phosphorus that can be used by plants and animals • Oxygen production • Normal flora: digestion, vitamin production etc • Cellulose digestion by protozoa in termite gut • Vitamin K production by human intestinal flora

18. The Role of Microbes in Nature: Sometimes Harmful • A small percentage of all microorganisms are involved in diseases • Humans, animals and plants can be affected • Opportunistic and obligate pathogens • Diseases linked to • microbial proliferation (e.g. pus, pneumonia) • toxic substances (e.g. botulism, liver cancer)

19. Multiple Choice #1 An organism that contains a nucleus and a cell membrane is: • Virus • Prokaryote • Helminth • Archaea

20. Multiple Choice #2 Choose the correct form of naming a microbe: • Pseudomonas maltophilia • P. maltophilia • Pseudomonas m. • P. m.

21. Brief History of Microbiology • Development of tools to study microbes • Microbes exist • Microbes cause disease • Humans have a defense system • Drugs that kill microbes can be developed • Microbes can be exploited to the benefit of humans

22. Tools to Study Microbes • For identification • Optics (microscope) • Glass slides • Dyes • Culture media, inoculation material • Biochemical and molecular genetic assays • Advanced tools to study their role • In vitro models • Animal models

23. Milestones in Microbiology: Microbes exist • ~ 1600 Galilei: Lenses for use in a microscope • 1665: Robert Hooke described cells • 1676 Van Leeuwenhoek: first recorded description of microbes called “animacules” • 17th/18th century: spontaneous generation • Living things arise from non living matter • 1858 Virchow proposes concept of biogenesis • Cells arise from living cells • 1861 Pasteur disproves theory of spontaneous generation (and proves concept of biogenesis)

24. Pasteur’s Proof of Biogenesis • Pasteur’s S-shaped flask kept microbes out but let air in Fermentation, Pasteurization

25. Milestones in Microbiology: Microbes cause disease • 1847 Semmelweis • childbed fever • 1867 Lister • antiseptic surgery with phenol • 1876 Koch • First proof that microbes cause disease: Bacillus anthracis causes anthrax • 1884 Gram stain developed, Koch’s postulates formulated http://www.chemistryexplained.com/images/chfa_03_img0510.jpg http://www.cdc.gov/ncidod/eid/vol7no2/images/cover_final_rgb.jpg http://www.acponline.org/bioterro/anthrax/graphics/cutaneous.jpg

26. Koch’s Postulates • Microbe must be present in every case of disease and not in the healthy one. • Microbe must be isolated in pure culture. • When inoculated into a healthy tissue the same disease must arise. • From this diseased tissue the same microbe must be re-isolated in pure culture.

27. Koch’s Postulates

28. Milestones in Microbiology: Humans have a defense system • 1798 Jenner: cow pox vaccination • 1884 Metchnikoff: phagocytosis • 1890 Ehrlich: theory of antibodies • 1921 Fleming: lysozyme

29. Milestones in Microbiology: Drugs that kill microbes • End of 19th century: dyes • 1910 Ehrlich: Firstchemotherapeuticum(salvarsan: arsenic compound to treat syphilis) • 1928 Fleming: first antibiotic (penicillin) • First successful treatment in 1942

30. Milestones in Microbiology: Microbes can be exploited • Food preparation (fermentation) • Bread, yogurt, kim-chi, cheese, beer, wine and many more • Production of Chemicals • acetone, butanol, alcohol, organic acids and many more • Drugs • Antibiotics, some cancer drugs • Biotechnology • Bioremediation • Clean up of BP oil spill • Genetic engineering • Recombinant drugs • Immunoassays • Rebecca Lancefield: serotyping of Streptococcus spec.

31. Anything left to do for Microbiologists? S. aureus Biofilm • Emerging infectious diseases and topics • Avian Flue (H5N1) and swine flu • West Nile virus encephalitis • Mad cow diseases (prions) • E. coli O157:H7 • Biofilm • On teeth, mucosal surfaces, rocks, medical devices • Hard to penetrate, source of recurrent infections • Emerging antibiotic resistance • Vancomycin resistant staphylococci and enterococci • Multidrug resistant tuberculosis strains • Resistance among malaria strains

32. Important to Remember • Microbial agents include prokaryotes, eukaryotes and acellular agents • Prokaryotes are cells without nucleus • Bacteria, archaea, fungi, algae, and protozoaare in the MICROMETERrange (mm) • Viruses, acellular agents, are in the NANOMETERrange (nm)