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 Death

1.19 x 10610. Accidents 33,86510.Septicemia

1.27 x 1069. Malaria40,9709. Kidney problems

1.57 x 1068. Tuberculosis58,8708. Alzheimer disease

1.80 x 1067. Diarrheal disease

65,6807. Flu & Pneumonia

2.75 x 1066. Chronic LRD*73,2506. Diabetes

2.78 x 1065. HIV/AIDS106,7405. Accidents

3.33 x 1064. Cancer124,8004. Chronic LRD*

3.88 x 1063. Res infection 162,6703. Stroke

5.51 x 1062. Stroke557,2702. Cancer

8.12 x 1061. Heart Disease696,9501. Heart Disease

DeathsWorldwideDeathsUnited States

* 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