Microbiology
Chapter 1
Part I
Introduction to Microbiology
Scope of Microbiology Microbes
Life forms which require magnification for viewing
Ubiquitous Each group has a distinct set of biological
characteristics Single celled vs. multi-celled Prokaryotic vs. eukaryotic Cell wall vs. no cell wall Autotrophic vs. heterotrophic Cellular vs. acellular
Prokaryotic vs. Eukaryotic
Assigning Characteristics Bacteria
Protozoa
Fungi
Algae
Helminths
Viruses
Assign common characteristics to each group
(Top) Coccidioidomycosis Arthrospores (Bottom) Development of Arthrospores Into spherule in lung tissueFungal Infection of the lung
Schistosoma (worms) at two different stages of development – liver Disease and other symptoms
Staphylococcus AureusGram positive bacteriaStaph infections and MRSA
Trypanosoma Eukaryotic pathogenAfrican Sleeping Sickness
Treponema pallidumBacterial spirocheteCauses syphilis
Mycobacterium tuberculosis. Acid fast bacteria (shown in pink) like this causes TB and leprosy. Light blue is Staph epi, a commonbacteria cocci which inhabits theSkin. Not a common pathogen
Herpes Virus
Size Comparisons
What Do Microbes Do?
PhotosynthesisDecomposition
Soil Fertility&
Microbial Ecology
Microbial Physiology &
Fermentation ofCheeseWineBread
Genetics, Gene
Regulation &
Biotechnology
Bioremediation Oil Eating Bacteria &
FungiWater
Purification
Infectious Disease
& Immunology
Ch 4, 7, & 26 Ch 8 & 27 Ch 9 & 10
Ch 27 Briefly Need an
Environmental & Applied
Micro Course
Ch 14 – 16&
Ch 18 - 25
Part II
Historical Figures in Microbiology
Superstition of Microbiology Spontaneous generation
For thousands of years people believed that living things arose from vital forces present in non living matter
Mushrooms appearing on rotting wood Afflicted people were thought to be cursed
Controversy between… Abiogenesis and biogenesis
First Look at Microbes In the 1600s
Robert Hooke (English) reported that living things were composed of little boxes or cells
Antonie van Leeuwenhoek construction microscopes which could magnify 300X
Described microorganisms that he observed in teeth scrapings & rain water
Abiogenesis vs. Biogenesis Franceso Redi
He wanted to ascertain whether maggots arose from some “vital force” of the meat or were offspring of flies
Abiogenesis vs. Biogenesis Conclusions of Redi’s Experiment
This and related experiments proved that complex animals such as insects and mice develop through biogenesis
However, meat leaf out but covered with gauze would still rot
Therefore, the idea that simpler organism could arise from abiogenesis was still accepted
Proving that Microbes Are Present in Dust Particles Jablot’s vs. Needham’s Experiment
Jablots experiment supported the idea that microbes are present in the air
Proving that Microbes Are Present in Dust Particles However, support for Jablot’s experiment
faltered when Needham’s results were reported
Needham performed the same experiment with mutton gravy
Microbial growth was in both containers What do you think happened here?
These disputes would be put to rest with Louis Pasteur’s work
Proving that Microbes Are Present in Dust Particles
Pasteurization
Pasteur also demonstrated that spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called pasteurization
Lister’s Work English physician advanced the idea of
antisepsis in health care setting 1860’s Dressed wounds with carbolic acid
(phenol) Reduced deaths among patients by 2/3 Listerine Mouthwash
Koch’s Postulates 1876 Robert Koch provided proof that a
bacterium causes anthrax and provided the experimental steps, postulates, used to prove that a specific microbe causes a specific disease
Koch was a physician and Pasteur’s young rival
Koch’s Postulates
Mouse dies with sores
Take scraping and plate on agar
A heterogeneous population of bacteriaGrow – which one is the causative agent
Isolate all different strains and types and inject into healthy mice and see which micedevelop similar phenotype and symptoms
Take a sample again from mice which diedof same symptoms and isolate the causative agent again
Koch’s Postulates
A sequence of experimental steps to relate a specific microbe to a specific disease
Koch’s Postulates
Used to prove the
specific causative
agent of an infectious
disease
Jenner’s Work Observed that milkmaids did not acquire
smallpox Milkmaids were exposed to chronic low
doses of cowpox and therefore acquired specific immunity
1796 Jenner inoculated a person with cowpox virus and found this person was then protected against acquiring small pox
This protection is known as immunity Called vaccinatin from vacca for cow
Alexander Fleming’s Work In 1928 Fleming
discovered the first antibiotic by accident
He observed that Penicillium fungus secreted a substance which killed bacteria
Explain why a fungus would do this
In 1940s penicillin was tested clinically and mass produced
Germ Theory of Disease All of these aforementioned people and
others helped give rise to the germ theory of disease
Germ Theory states that microorganisms can invade other organisms and cause disease
Before this many time politics and religion would spur on erroneous theories
Part III
Introduction to Disease
Chronic vs. Infectious Disease Chronic
Disease which persists over a long period of time
Atherosclerosis, cancer & heart failure Infectious
Organism enters and tissues & grows Bacterial – Prokaryotic Viral – Acellular Protozoan – Eukaryotic
Causes symptoms in patients
Conquering Infectious Disease The triumph over infectious disease?
Antibiotics discovered in 1940s Vaccinations routinely delivered in the 1950s
through today Eradication of polio and small pox
But then… MRSA Drug resistant TB HIV Ebola Avia Flu And more
Conquering Infectious Disease What went wrong?
Medical advances Older and sicker people live longer More susceptible to garden variety microbes
Population is more mobile Emerging diseases
Encroachment of humans into wild habitat Rapid evolution and biochemical changes to
microbes Microbes have a quick generation time
All Diseases
Old StandardsSyphilisMeasles
Staph InfectionsChicken Pox
EmergingAvia Flu
Antigenic shift eventHIV in the 80’s
West Nile in US in 2001Continental travel
ReemergingTuberculosis - TB
New drug resistant strains
Immunocompromised patients
Top Causes of DeathUnited States Deaths Worldwide Deaths
1. Heart Disease 696,950 1. Heart Disease 8.12 x 106
2. Cancer 557,270 2. Stroke 5.51 x 106
3. Stroke 162,670 3. Res infection 3.88 x 106
4. Chronic LRD* 124,800 4. Cancer 3.33 x 106
5. Accidents 106,740 5. HIV/AIDS 2.78 x 106
6. Diabetes 73,250 6. Chronic LRD* 2.75 x 106
7. Flu & Pneumonia 65,680 7. Diarrheal disease 1.80 x 106
8. Alzheimer disease 58,870 8. Tuberculosis 1.57 x 106
9. Kidney problems 40,970 9. Malaria 1.27 x 106
10.Septicemia 33,865 10. Accidents 1.19 x 106
* Stands for lower respiratory diseaseInfectious Diseases are shown in red
Infectious Disease Statistics
Part IV
Taxonomy & Biological Classification
Organizing Life Classification
Orderly arrangement of organisms into groups that indicate evolutionary relationships
Nomenclature Assigning names to various taxonomic
rankings Identification
Correct placement of organism into taxonomic scheme
Taxonomy Origins of organizing biological life
Carl von Linne or Linnaeus 1701 – 1778 System of recognizing and defining properties
of living organism followed by the placement into specific slots
Grouped according to similar properties Grouped according to evolutionary relatedness Constantly being revised and refined
Taxonomy
Nomenclature Scientists use a standard binomial system Overseen by an international group
Verify that standard procedures were followed Ascertain the uniqueness of each name Make sure no other name exists
Nomenclature Staphylococcus aureus
Staphule – bunch of grapes Aureus – golden
Campylobacter jejuni Kampylos – curved Bakterion – little rod Jejunum – section of small intestine
Giardia lamblia Alfred Giard – French microbiologist Vilem Lambl – Bohemian physician
Evolution & Phylogeny Evolution
All new species originate from preexisting species
Closely related organism have similar feature due to evolution from common ancestral forms
Phylogeny Tree of life Classification based on evolutionary
relatedness
Whittaker’s System
Whittaker’s System Although used for many years this system
has problems in terms of evolutionary relatedness
Kingdom Protista Autotrophs & heterotrops are groups together
Archaea Although these organisms are prokaryotic they
are more closely related to eukaryotic cells
Solution to Whittaker’s Tree Biologist no longer group organisms into a
5 kingdom system Currently a three domain system
Many original kingdoms still work Plants, animals, fungi
However, Kingdom Protista & Kingdom Monera have been extensively reorganized into many different kingdoms
Three Domain System