Chapter 1

History of Microbiology

Today’s Class

• General Information

• Course Outline

• Lab and Lab Schedule

• Chapter #1 Almco’s Fundamentals of Microbiology J.C. Pommerville– Microbiology: Then and Now

Books

• Alcamo’s Fundamentals of Microbiology

• Lab manual: Leboffe, M. and Pierce, B. Microbiology Laboratory Theory and Application

Instructor• Thomas Graham• Background 15 years Health Canada

– Escherichia coli O157:H7 and other VTEC– Salmonella and Campylobacter– Master’s Thesis on Listeria monocytogenes

• thomas.graham@lethbridgecollege.ab.ca• Best way to get hold of me is through Email.• I will set-up regular office schedule.• I check my Email every day.• WebCT post all information there as well

(hopefully).

Course Outline• The class is broken down into three

sections

• After each section there will be an exam

• Two midterms and one final

• Also, during class there will be two assignments– Assignment #1 will be on describing a

infectious bacterial pathogen.– Assignment #2 Group presentation on fungal,

parasitic or viral infections in humans.

Lab Schedule

• No, there is no lab this week (orientation, safety and microscopy).

• Two lab assignments (handouts).• You must have a lab coat you can ask Cherie if

there are any left for sale CB4002.• Miss 2 labs and you will fail unless you have a

medical reason.• Marking sheet will be provided you are

responsible for bring them to each lab.• Must go down to maintenance and have your

card swiped to get access to the lab.

Do you have any questions?

• Speak now or forever hold your peace!!!

• What are your majors (ie are you all nurses ?)

• Major problem in Microbiology is learning all the new terms.

Chapter 1Alcamo’s

Microbiology: Then and Now

Microorganisms• Microorganisms are ubiquitous (every where)

throughout the world.

– Antarctica, tallest mountain and deepest part of the sea.

• Microorganisms are defined as any organism

too small to be visible to the naked eye (not really true mushrooms).

• Most microorganisms are harmless and wide variety are beneficial to life and without them we would be soon be over run with dead plant and animal material.

Microorganisms

• They produce around 50% of the oxygen that we breath.

• However, when people hear the words viruses, parasites and bacteria they automatically think of infection and disease.

• The pathogens (any microbe that causes disease) have caused a number of major epidemics plague, cholera and small-pox, influenza, AIDs.

Tragedy In Eyam• 1665 – 1666

• A tailor brought some plague infected fleas in cloth to the village.

• Soon the village had its first cases of the plague.

• The village folks decided to stay in their village to insure that the other villages did not get infected.

• 260 of 350 died

Nursery Rhyme

• A ring-a-ring of rosies (rose colored blotches)

• A pocketful of posies (flowers used to lessen the stench of the dead)

• A tishoo! A tishoo! (sneezing)

• We all fall down. (death)

THE BEGINNINGS OF MICROBIOLOGY• Robert Hooke, 1665

– Published “Micrographia”– Developed first microscope– Sliced a cork and observed it’s micro structure he called

“cella”– Poor magnification 25 x

• Anton van Leeuwenhoek, 1674– Developed a lens system from ground glass – Magnify up to 300 times– Looked at water, tooth scum and faeces– He described “Animalcules” tiny animals– Looked at teeth scum and suggested that the population

of animalcules on your teeth was larger then the people in many big cities

Anton van Leeuwenhoek, 1674

Leeuwenhoek’s Lens System

The Transition Period Does Life Generate Itself Spontaneously?

• Basis of the doctrine of spontaneous generation.

• Aristotle fourth century B.C. suggested that flies, worms and other small animals arose spontaneously from decaying material without parents.

• Jan Baptista van Helmont 1600’s observed rats that originated from wheat bran and old rags and no parents.

Spontaneous Generation

• Others saw worms produced from rotting meat and frogs produced from slime.

• The only one who did not believe these ideas was Leeuwenhoek who had observed tiny eggs with his special microscope.

• Fransesco Redi's, 1668 set out to dispute the idea of spontaneous generation

Redi’s Experiment

• He set-up a number of experiments where he covered some jars of meat with fine lace cloth to prevent flies from entering and laying eggs.

• In these jars there were no maggots.

• In other jars he did not cover he found maggots.

• He suggested that the only way that this could happen was due to flies laying invisible eggs that hatched and gave rise too maggots.

Francesco Redi

This was the beginnings of experimental science• Needham's, 1748 had objections

– He had followed Redi’s method but used boiled gravy and a cork in jar– His however gave rise to the “animalcules”– He was rewarded with a membership in the Royal Society of London for

disproving Redi– It was actually one of the first documented experimental errors

(contamination of the cork).

• Spallanzani's, 1767 criticized Needham’s work– Spallanzani boiled meat and vegetable broth for long periods – He then made 3 flasks; one open to the air, 1 corked like Needham’s

and the last flame sealed the neck of the flasks– The first two grew “animalcules” the last one did not.

• Needham countered by saying Spallanzani had killed the vital life force by over heating and sealing the jars from the life giving air.

Finally Louis Pasteur Ended the Debate

• He developed an elaborate experiment using four different flasks.

• One was left open to the air.

• One was sealed by melting the glass.

• One had an open tube with heat that would sterilize the air.

• The final tube had a long bent neck which prevented microbes from reaching the broth.

Read The MicroInquiry 1

Alcamo’s Fundamentals of Microbiology Pg 12-13

The Idea That Microorganisms May be the Cause of Disease

• Edward Jenner’s, 1798– Developed an inoculation against smallpox that

interrupted transmission of the disease.– First vaccination procedure.– He had no idea what caused smallpox or the mode of

transmission.

• Ignaz Semmelweis, 1847– Many pregnant women were dying of puerperal

(childbed) fever a blood poisoning resulting from bacterial infection of the uterus.

– He determined that student physicians would come from autopsies to delivering babies.

– He first suggested hand scrubbing chlorine and lime.– Amount of deaths dropped dramatically.

Epidemiology – scientific study from which health problems are identified, including source, cause and

mode of transmission

• Semmelweis may have used epidemiology first John Snow, 1854 took it to a new level.

• Snow used it during an Cholera outbreak in London.

• Interviewed rich and poor the sick and healthy people.

• Plotted locations of each cholera case.

John Snow

• Traced source of outbreak to sewage contaminated water pumps in the streets.

• Identified drinking water as the source without isolating the causative agent.

• He ordered the removal of the handles off of all public water pumps.

Spatial Association Between E. coli O157 Infection and Cattle Density in Ontario (1990 - 1998)

Cases of human O157:H7 infections Cattle density (Cattle to Human population ratio)

%a%a %a%a$

L. Ontario

L. Erie

L. Huron

#

Toronto

#

Ottawa

VTEC 1990 - 1998 (rate /100,000 pop.)low (0 - 2.73)median (2.74 - 5.14)high (5.15 - 6.60)very high (6.61 - 8.26)

N

L. Ontario

L. Erie

L. Huron

#

Toronto

#

Ottawa

Cattle - Pop ratio (%)no cattlelow (0 .1 - 9.57)median (9.58 - 80.42)high (80.43 - 104.40)very high (104.41 - 272.93)

N

Health CanadaSanté Canada

Walkerton

Michel et al. (1999)

The Classical Golden Ageof Microbiology

(1854 – 1914)

Germs Cause Infectious Disease

• Louis Pasteur proposes that germs cause infectious disease.

• First he was asked to determine why wine went sour by a local merchant.

• 1857 Pasteur found that wine was produced from the fermentation grape juice by microorganisms (yeast), not the breakdown of chemicals in grapes, as was believed at the time.

Louis Pasteur

• He proved this by removing all the yeast from the wine. This stopped fermentation.

• Then he returned the yeast and fermentation resumed.

• He also showed that the souring of the wine was the result of bacterial contamination.

Microorganisms were small reproducing factories.

• From the wine work Pasteur’s wrote a paper in 1857 and in it proposed that germs were related to human illness and formulated the germ theory of disease.

• Germ Theory Of Disease: stated that microorganisms are responsible for many diseases.

• He also suggested in the same paper, that to control the souring of wine, that had initially lead to this work, a wine maker would only need to heat the wine to kill the bacteria and the wine would be fine.

• This process was accepted and was termed pasteurization many years later.

Pasteur’s work Contributes To Disease Identification and Control

• In 1859 Louis Pasteur’s daughter Jeanne died of typhoid and this lead him to focus most of his work in to controlling diseases.

• He demonstrated that bacterial broth of Cholera inoculations made animals ill but was unable to show the true causative agent.

• His critics had claimed that the toxins in the broth had caused the animals to be sick not the bacteria.

• In 1865, his two year old daughter Camille died of blood poisoning.

Silkworms

• In 1865, Pasteur turned to looking at Pebrine a disease in silkworms to isolate disease.

• In this work he isolated a protozoan as the cause of the silkworm disease.

• By changing feed and separating the health silkworms from sick Pasteur he stopped the spread of the disease and saved the silkworm industry in France.

• However, at the age of twelve Pasteur’s third daughter Cecille died of typhoid disease.

• This lead Pasteur to work on human diseases.

Hansen, Obermeier, Cohn and Lister• Pasteur work stimulated other researchers to look at

microorganisms as disease causing agents.

• Gerhard Hansen identified bacteria in leprosy patients.

• Otto Obermeier described bacteria in the blood of relapsing fever patients.

• Ferinand Cohn discovered that bacteria could divide into large numbers (replication).

• Joseph Lister– suggested that gangrene was caused by bacteria.– To block transmission of disease during surgery he used carbolic acid to

clean wounds and surgical equipment.

Robert Koch• Robert Koch focused on anthrax.

• Anthrax was a deadly bacterial disease that was killing a large number of cattle and sheep in Germany.

• Koch set-up a lab in his house to do his studies.

• In 1875, Koch injected mice with blood from an infected sheep and the mice died.

• He noted at autopsies the mice had died from the same disease as the sheep.

Koch• He was able to isolate a rod shaped bacteria from the

blood of an ox’s eye.

• From hours of tedious observations of these bacteria he observed that these bacteria multiplied into tangled threads then formed into highly resistant spores.

• He took some of the spores and injected them into mice.

• The infected mice soon showed the signs of anthrax.

• Following autopsies he was able to see swarms of the same bacilli in the blood of these mice

Koch Postulates

Koch’s Postulates

• Koch procedures became known as “The Koch Postulates”.

• These procedure gave a procedure that can be used to identify and isolate germs from infectious disease.

• Therefore, can relate specific organisms to a specific disease.

• This method of pathogen detection is still used today.

Koch Developed Pure Culture Techniques for Isolating Bacteria • Koch developed a cultivation technique using sliced potatoes.

• He noticed that he could get small masses of bacteria on the potato which he termed colonies.

• Colonies – are viable mass of microorganisms, usually of a single type.

• He soon added gelatin to broth and made it solid.

• He inoculated it with bacteria and next day he could see colonies.

• This lead him to develop a pure culture method.

• Pure Culture – an accumulation of one type of microorganism formed by the growth of colonies of that organism

Pure Culture Inoculation

• Koch now could quickly get pure cultures to inoculate into animals to test for infection.

• In 1881, Koch published his methods for pure culture.

• Koch received a letter of congratulations from Pasteur who had never been able to isolate infectious bacteria.

Agar and Petri Dish • Koch did not like the gelatin he had used as a solidifying agent.

• Turn liquid at high temperatures and by chemicals produced by the microorganisms.

• A wife of one of Koch’s associates had suggested the use of a seaweed extract (agar) as a solidifying agent.

• Fanny Eilshemius had used agar as a jelling agent for her jams and jellies.

• Today it is still the most used solidifying agents for culture media.

• Petri dishes were also invented by an assistant of Koch named Julius Petri.

Competition fuels the study of infectious diseasePasteur and Koch

• Pasteur lab: focused on infection and immunity.

• Anthrax (1878)• Anthrax showed that chickens did not become infected by anthrax because

their body temperature was 42ºC.

• but did if their temperature was cooled to 37ºC.

• Cholera (1880)• Developed a weakened bacteria that does not cause chicken cholera.

• He injected the weaken bacteria into chickens and then treated them with the lethal strain of cholera bacteria.

• The chickens did not develop disease..

• lead to the principles for vaccination

Koch

• Koch lab: focused on isolation, culture, and identification.

• Isolated the causative agent for caused tuberculosis, typhoid, and diphtheria bacilli.

• Kitasato a scientist working in Koch’s lab isolated tetanus bacillus Clostridium tetani.

Pasteur• Elie Metchnikoff working in Pasteur’s lab

discovered phagocytes an immunological defensive process were white blood cells engulf and destroy microorganisms.

• **1885 Pasteur successfully immunized a small boy, Joseph Meister, infected with rabies with bits of tissue isolated from the brain of a rabid animal.

Other Global Pioneers Contribute to Microbiology

• Nicolle - showed that lice transmitted typhus.

• Calmette - developed immunization process for tuberculosis.

• Bordet – isolated pertussis bacillus.

• Pfeiffer – identified the cause of meningitis.

• Ehrlich – working on syphilis developed first synthetic drug “magic bullet” out of arsenic.

• Ross – mosquitoes caused malaria.

• Bruce – tsetse flies cause sleeping sickness.

Microbes represent a diverse group of organisms

• Fungi

• Protista

• Bacteria

• Viruses

Fungi

• Mushrooms, puffballs, truffles, molds and yeasts.

• 70,000 species.

• May be as many as 1.5 million species because most have not been discovered.

• Grow best in warm, moist places.

Fungi• Secrete enzymes that breaks down nutrients,

therefore, grow on food source.

• Produce useful products.– Antibiotics like penicillin

• Used by food and alcohol industry.

• Together with bacteria play a major role in decomposing dead matter.

Protista• Single-celled protozoa and algae.

• 200,000 species.

• Some can be free-living others need plant or animal hosts.

• Locomotion is achieved by flagella, cilia or crawling.

Protista• Protista obtain food by absorbing from

surroundings or by eating small animals and plants.

• Algae make their own food through photosynthesis.

• Most protozoa are important as food for other animals (snails, clams, and Sponge Bob Square Pants).

• However, some cause disease– Malaria– Sleeping sickness– Diarrhea

Bacteria• 10 million species and billions that have not yet been

discovered.

• Simple singled-celled organisms that do not have a nucleus.

• Divided into two groups– Eubacteria– Archaea

• Three shapes– Bacillus (rod shaped)– Coccus (spherical)– Spirillium (spiral)

Bacteria• Decomposers sewage treatment.

• Food industry yoghurt and cheese.

• However, also responsible for food spoilage.

• A number are pathogenic

– Tuberculosis– Typhoid– Plague– Hamburger Disease– Etc.

Viruses• 3,600 known types of viruses.

• Structurally simpler than all other microbes.

• Not true cells.

• Core of nucleic acid (DNA or RNA) surrounded by a protein coat.

• Features used to identify viruses– Nucleic acid type, size, shape and biological properties

• Small number cause human disease– Smallpox, polio, measles, flu, AIDs and SARs are some

examples

THE SECOND GOLDEN AGE OF MICROBIOLOGY (1943-1970)

• Development of Genetics depended on work with microorganisms.

• In 1943 Salvador Luria and Max Dulbruck used Escherichia coli to show that bacteria can form spontaneous mutations that generates resistance to viral infection to bacteria phage.

• This research also showed other researchers that bacteria, especially E. coli, were excellent model systems for studying general principles of genetics.

• Beadle and Tatum used fungus, Neurospora, to show that one gene codes for one enzyme.

• 1953 Hersey and Chase showed that DNA was the substance of genetic material using bacteria viruses (bacteriaphage).

• Watson and Crick worked out the structure of DNA

MICROBIOLOGY (1943-1970)

New Microscopes Opened Up New Worlds• New type of microscope was developed.

• Electron microscope could magnify objects 1000 times better then the light microscope.

• This allowed researchers to see that bacteria were actually cellular like other microbes.

• However, they were organized differently than other microbes.

• Allowed researchers to classify two types of cellular organizations:– Eukaryotic cells

• DNA surrounded by a membrane envelope = cell nucleus• Karyotic with nut

– Prokaryotic cells• DNA not surrounded by an envelope• Without nut

Chemotherapy and antibiotic are used to combat infectious disease.

• After the relationship between microorganisms and disease was established the search for substances to destroy them took off.

• Chemotherapy – treatment of disease with chemical substances.

• Synthetic drugs – prepared from chemicals in a lab.

• Paul Ehrlich, 1910 synthesized the first synthetic drug.

Synthetic Drugs• Ehrlich, said that his chemical was the “magic bullet”.

• It was derived from arsenic.

• Ehrlich showed that it was very effective at curing syphilis.

• The chemical was called salvasan (Gave salvation to syphilis suffers).

• Soon more drugs were synthesized that could destroy microorganisms.

• A large number of these were made from derivatives of clothing dyes.

A Fortunate Accident

• Alexander Fleming, 1929, left bacterial plates on bench and left for a two week holiday.

• When he returned he found that a mold (Penicillium) had killed some of the bacteria that were near to it.

• Fleming then set out to find out what had occurred.

• He soon had developed an assay for the detection of the antimicrobial substance from Penicilium.

• He termed this new substance penicillin.

Antibiotics

• Florey and Chain, 1940 purified large amounts of penicillin and carried out trials to show the antimicrobial potential of penicillin.

• Gerhard Domagk, 1932, discovered the first sulfa drugs that prevented the production of folic acid in bacteria.

• Selman Waksman discovered actinomycin and streptomycin he called these two new substances “Antibiotics”.

• Antibiotics: Are defined as any chemicals produced naturally

from bacteria and fungi that act against other microorganisms.

• The research into antibiotics took off in World War II to help treat infections in war casualties.

• In 1969, the US Surgeon General declared that it was time to close the book on infectious diseases.

Antibiotics

• However, many of the drug companies who were making a lot of money from these antibiotic drugs.

• Had failed to mentioning one little problem.

• Many of the bacteria were starting to show signs of resistance to the antibiotics, as early as the 1950’s

End of the Second Golden Age

• Near the end of the 1960’s many believed that the antibiotics would soon bring an end to the age of infectious disease.

• This lead to a decrease in research funding for microbiology.

• Researcher’s started to take all the information learned from bacteria research and apply it to research on animals.

The Third Golden Age of Microbiology (Now)• Again Microbiology finds itself in the front lines of

research.

• A lot of this is due to biotechnology research era.

• Allows for the complete DNA sequencing of bacterial genomes (Genomics).

– Development of microarrays.

• Also, infectious diseases are still around and are getting a little nasty.– More than a 11 million people die from tuberculosis, malaria,

lower respiratory infections and diarrheal diseases each year.

Microbiology Challenges

• Antibiotic resistance– Increasing inability to treat infections.

– More and more pathogens are becoming resistant to antibiotic antimicrobial drugs.

– “Superbugs” MRSA, VRSA, others?

– One bonus is microbial genomics.

– Knowing the genes may be able to developed treatments to attach bugs.

– Also vaccination development.

Emerging and Reemerging Diseases

• Emerging diseases are the diseases that we have never seen before.

– AIDs, hantavirus pulmonary syndrome, Lyme disease, Mad Cow and SARs.

• Reemerging diseases the ones that have been seen before but are again having a resurgence (usually due to antibiotic resistance).

– Cholera, Tuberculosis, Dengue fever, West Nile

http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20070824/west_nile_sask_070824?s_name=&no_ads=

Bioterrorism

• Bioterrorism – use of biological agents to cause death and disease on large populations.

• Small Pox, Anthrax, Plague

• On the positive sides to this has focused a lot of funding dollars back into research of infectious microorganisms and molecular epidemiology.