Microbial World. Basim R. Sahar

Transcription

1 Microbial World Basim R. Sahar

2 Microbes do benefit us, but they are also capable of causing many diseases Pneumonia Whooping Cough Botulism Typhoid Fever Measles Cholera Scarlet Fever Mumps Syphilis Gonorrhea Herpes 1 Chlamydia Tuberculosis Herpes 2 Meningitis Tetanus RMSV Strep Throat Lyme Disease AIDS

3 History of the Study of Microorganisms 1665 Robert Hooke little boxes - cells Cell Theory - all living things are made up of cells

4 Anton van Leeuwenhoek st person to actually see living microorganisms wee animalcules

5 Spontaneous Generation Theory that life just spontaneously developed from non-living matter Example: toads, snakes and mice - moist soil flies and maggots - manure and decaying flesh

6 Experiments to disprove Spontaneous Generation Francesco Redi 1668 Rudolph Virchow 1858 Theory of Biogenesis Cells can only arise from preexisting cells Louis Pasteur 1861

7 Pasteur designed special swan-necked flasks with a boiled meat infusion Shape of flask allowed air in (vital force) but trapped dust particles which may contain microbes

8 Germ Theory of Disease Hard for people to believe that diseases were caused by tiny invisible wee animalcules Diseases, they thought, were caused by: demons witchcraft bad luck the wrath of God curses evil spirits

9 Robert Koch - 1st to prove that bacteria actually caused diseases 1876 Microbial Etiology of Infectious Disease etiology - the cause of a disease Established scientific rules to show a cause and effect relationship between a microbe and a disease Koch s Postulates

10 Koch s Postulates 1. The same organisms must be found in all cases of a given disease. 2. The organism must be isolated and grown in pure culture. 3. The isolated organism must reproduce the same disease when inoculated into a healthy susceptible animal. 4. The original organism must again be isolated from the experimentally infected animal.

11 Exceptions to Koch s Postulates 1. Some organisms have never been grown in pure culture on artificial media Treponema pallidum - Syphilis

12 Exceptions to Koch s Postulates Mycobacterium leprae Leprosy Never been grown in pure culture on artificial media Abdominal cavity of the Seven Banded Armadillo

13 Exceptions to Koch s Postulates In exclusively human diseases, it is not morally acceptable to inoculate a deadly pathogen into a human guinea pig HIV

14 Koch established the Microbial Etiology of 3 important diseases of his day 1. Cholera (fecal-oral disease) Vibrio cholerae 2. Tuberculosis (pulmonary infection) Mycobacterium tuberculosis 3. Anthrax (sheep and cattle) Bacillus anthracis

15 Anthrax Bacillus anthracis Gram (+), non-motile, aerobic, spore forming rod Streptobacilli with central spores Livestock Sheep, cattle, goats Humans Handle hides, wool, goat hair, handicrafts from the Middle East made from animal products

16 3 Forms of Human Anthrax 1. Cutaneous Anthrax Enters thru cut or abrasion Results in painless ulcer (1-3 cm) with black (necrotic) center About 20% mortality rate in untreated cases

17 2. Gastrointestinal Anthrax Contaminated meat Abdominal pain, fever, vomiting blood, severe diarrhea 25% to 60% mortality rate

18 3. Inhalation Anthrax Initial symptoms resemble common cold Progress to severe breathing problems and shock Usually results in death 1-2 days after onset of acute symptoms Mortality rate 99% in untreated cases Treatment usually not effective after symptoms are present

19 Anthrax as a Biological Weapon Deadly if not treated early Spores can be produced in large quantities using basic knowledge of biology Spores may remain viable for years (60 at least) Spores can be spread Missiles, rockets, bombs, mail, crop dusters? No cloud or color No smell No taste Antibiotics only effective if administered early (within hours)

20 Koch - 1st to use Agar to solidify culture media

21 Golden Age of Microbiology Pasteur Pasteurization Fermentation Joseph Lister Phenol to treat surgical wounds 1 st attempt to control infections caused by microoganisms Robert Koch Koch s Postulates Edward Jenner vaccination Paul Erlich 1 st synthetic drug used to treat infections Salvarsan - arsenic based chemical to treat Syphilis salvation from Syphilis

22 Naming of Bacteria Genus and species - Binomial System of Taxonomic Classification Information usually given: 1. Describes an organism 2. Identifies a habitat 3. Honors a scientist or researcher

23 Bacterial Morphology Bacilli Cocci Spiral

24 Arrangements Staphylo Strepto Diplo Sarcinae Tetrad Vibrio bacter bacterium comma shaped bacilli bacilli