Milestones in microbiology

BY: DR. NAZIA
1ST YEAR POST GRADUATE
DEPARTMENT OF MICROBIOLOGY

 INTRODUCTION
 THREE PERIODS OF DEVELOPMENT
-Pre 1865 period
-The Golden Era
-Modern Era/Post Golden era
 Discovery of Microbes
-Anton van Leeuwenhoek
- The Transition Period
-Theory of spontaneous generation
-Koch’s Postulates (the causal relationship
between a microorganism and a specific disease)
-koch’s Molecular Postulates
 -The Competetion Period

Microbiology is the study of living
organisms of microscopic size, which
includes bacteria, fungi, algae, protozoa
and viruses.
It aims to study their form, structure,
reproduction, physiology, metabolism and
classification.

Microorganisms are closely associated
with health and welfare of human beings.
Some are beneficial while others are
harmful.
 The science of microbiology did not start
until the invention of microscope in 16 th
century.

I ) Pre 1865 period where there was slow
accumulation of facts about bacteria and
existence of microbes.
II ) The period between 1865 and 1882
,also called as Golden Era where the
pioneering works of Louis Pasteur ,Robert
Koch, Lister etc made the most important
discoveries and laid the foundation of
microbiology

Modern Era/Post Golden era
 III ) The post 1882 period till date, the
modern period which has experienced
rapid developments in this field due to
accumulation of huge knowledge.

 Even before microorganisms were seen, some
investigators suspected their existence and responsibility
for disease.
 Among others, the Roman philosopher Lucretius
(about 98–55 B.C.) and the physician Girolamo
Fracastoro (1478–1553) suggested that disease was
caused by invisible living creatures.
 The earliest microscopic observations appear to have
been made between 1625 and 1630 on bees and weevils
by the Italian Francesco Stelluti, using a microscope
probably supplied by Galileo

 In 1665, the first drawing of a microorganism was
published in Robert Hooke’s Micrographia.

Antony van leeuwenhoek was the father
of microscopy.
He was a draper and haberdasher but
spent much of his spare time in
constructing simple microscope composed
of double convex glass lenses held
between two silver plates.

Magnification is 50 to 300 times.
Liquid specimen is placed between two
pieces of glass and shining light on them
at 450 angle.
This would provide a dark ground
illumination

These lens were of pinhead size but would
magnify over 200 times.
He used these lenses to inspect the quality
of cloth. But because of his curiosity he
started examining hair fibres , skin scales,
blood cells and even samples of his own
faeces.
At one point he observed tiny sperm cells
and speculated that they contain
microscopic embryos.

The only scientific group of those times
was the Royal Society of London. But the
correspondence was tenuos.
In 1673, Regnier de Graaf , a fellow of
Royal Society urged its members to
contact Leeuwenhoek following which they
did and he started sending his illustrations
and observations.

In september 1674, he filled a glass with
greenish cloudy water from a marshy lake
outside Delft and observed tiny organisms
which he called “animalcules”.
Later he examined materials from his own
teeth and faeces and many other materials
in which he found these animalcules.

In 1676 Leeuwenhoek sent his 8th letter to
the Royal Society. This has special
significance as it contains the first
description of microorganisims.
In 1680 he was elected to fellowship in the
Royal Society and he became one of the
famous men of his time along with Isaac
Newton and Robert Boyle.

A letter to the Royal
Society in 1683 included
drawings of what are now
believed to be bacterial
rods , spheres and spirals
He had sent about 200
letters to the Royal
Society

He died at the age of 90 in 1723 (his
longevity was an achievement itself).
He was a very suspicious and secretive
person and invited no one to work with him
nor did he show anyone how to grind
lenses or construct a microscope .
This is one of the reasons why the interest
in microorganisms waned after his death.

Biology in 1700s was a body of knowledge
without focus.
Basically it consisted of observations of
plant and animal life and attempts to place
the organisms in some logical order.
The dominant personality of that era was
Carolus Linnaeus a Swedish botanist
who brought plants and animals together
under one great classification.

 In 1718, Louis Jobolt published a review of
protozoa.
 In 1725, Abraham Tremblay described the
simple animal known as the hydra
 The then scientists could not believe that
microorganisms could cause infection.
 Rather they theorized that infectious diseases
were spread by an altered chemical quality of
the atmosphere, an entity called the
“miasma”.

 Miasma arose from the decaying or diseased
bodies known as miasms.
 The miasma theory figured prominently in
medical thinking well into the 1800s.
 As the years were passing on, some
biologists began to scrutinize the laws of
nature and question the origin of living things.
 Then the controversy about spontaneous
generation was answered by experimentation

In the 4th century BC, Aristotle wrote that
flies, worms and other animals arise from
the decaying matter without the need of
parent organisms.
This laid the basis for the theory of
spontaneous generation (that lifeless
substances could give rise to living
creatures).

In the early 1600s, the eminent Flemish
physician Jan Baptista Van Hemont lent
credence to the belief when he observed
that rats originate from wheat bran and old
rags.
Common people also supported his idea
as they could also see slime breeding
toads and meat generating maggots.

Among the first to dispute this theory was
the Florentine scientist Francesco Redi.
He reasoned that flies had reproductive
organs and suggested that they lay eggs
on exposed pieces of meat which then
hatch into maggots.
In 1670s he attempted to disprove the
belief that maggots arise from decaying
meat.
His work was one of the history’s first
experiments in biology .

In 1670s he attempted to disprove the
belief that maggots arise from decaying
meat.
His work was one of the history’s first
experiments in biology .

 An Italian cleric and
scientist, Abbe Lazzaro
Spallanzi criticized
Needhams work.
 He boiled meat and
vegetable broths for long
periods and then sealed
the necks of the flasks by
melting the glass.
 As a control he left some
flasks open to air,
stoppered some loosely
with corks and boiled
some briefly.

 After 2 days he found the control flasks
swarming with microorganisms but the sealed
flasks had none.
 His work was countered again by Needham
saying that he had destroyed the vital force of
life with excessive heat, and a few others
opined that air necessary for life has been
excluded.
 The controversy over this theory of
spontaneous generation continued which
encouraged scientists to experiment in
biology

 While the debate on spontaneous generation
continued, a few scientists studied on how
diseases were transmitted.
 In 1546, an Italian poet and scientist
Girolamo Fracastoro wrote “cotagion is
an infection that passes from one thing to
another”.
 He recognized 3 froms of passage – contact,
air and lifeless objects.
 His ideas were later interwoven by the
miasma theory and was given little credibility.

Athanasius Kirker reported microscopic
worms in the blood of plague victims-
which was not considered as other
scientists thought that what he had seen
were only blood cells.
Nor was Christian Fabricius taken
seriously when he suggested that fungi
cause rust and smut disease in plants in
1700s.

 On the contrary Edward Jenner received
many accolades when he discovered
immunization for smallpox in the year 1798,
though he could not explain the cause of the
disease.
 In the 1700s small pox was so rampant in
England and Europe that 1/3rd of the children
died before reaching the age of 3.
 Many were blinded and most were left
pockmarked for life.

 But those who have survived an attack of
small pox were immune for life.
 Thus the people started contracting a mild
form of disease where a doctor would make a
small wound in the arm and insert a few
drops of pus from a small pox skin lesion.
 Though mild form of the disease would
develop and the patients were resistant for
life, there were also cases of severe form of
the disease.

 Edward Jenner (a country surgeon) in 1700s
who learned that people who experienced
cowpox were apparently immune to smallpox.
 In 1796, a dairy maid named Sarah Nelmes
came to his office who had lesions of cowpox
on her hand.
 Jenner took material from her hand and
scratched it into the skin of a boy named
James Phipps.

Few weeks later he inoculated Phipps with
material from a small pox lesion.
Within days the boy developed a reaction
at the site but failed to show any sign of
small pox.
During the course of his experiments he
obtained cowpox material from cows

 In 1798 he published a historic pamphlet in
which he gave a description about his method
of preventing the fatal disease.
 Many physicians confirmed his findings and
within a few years his method of vaccination
(vacca = cow) spread through the world.
 By 1801 about 1lakh people in England were
vaccinated.
 Jenners experiments and interpretations of
vaccination served well as models for
accurate and careful laboratory work in
modern microbiology

 The first clear reference to smallpox
inoculation was made by
the Chinese author Wan Quan (1499–
1582) in his Douzhen xinfa published in
1549. Inoculation for smallpox does not
appear to have been widespread in China
until the reign era of the Longqing
Emperor (1567–1572) during the Ming
Dynasty.

In China powdered smallpox scabs were
blown up the noses of the healthy. The
patients would then develop a mild case of
the disease and from then on were
immune to it. The technique did have a
0.5-2% mortality rate, but that was
considerably less than the 20-30%
mortality rate of the disease itself.

By the mid 1800s enough knowledge had
accumulated to convince physicians that
diseases could be contagious and that
transmission could be interrupted.
Oliver Wendell Holmes (1843) in the USA
and Ignaz Semmelweiss in Vienna (1846)
had independently concluded that
puerperal sepsis was contagious.

Semmelweis a Hungarian physician in
1847 reported that the agent of blood
poisoning was transmitted to maternity
patients by physicians fresh from
performing autopsies in the mortuary.
He showed that hand washing in
chlorine water could stop the
spread of the disease.
But he was considered insane.

 John Snow a British physician traced the
source of cholera to the municipal water
supply of London during an 1854 outbreak.
 He reasoned that by avoiding the
contaminated water source, people could
avoid the disease.
 Thus both Semmelweis and Snow disproved
the theory of miasma and concluded that a
poison or unknown substance was
responsible for disease.

The first discovery of a pathogenic
microorganism was probably made by
Agostino Bassi (1835) who showed that
the muscaridine disease of silkworms
was caused by a fungus.

THE GOLDEN AGE OF
MICROBIOLOGY (1857- 1914)

Microbiology blossomed during this period,
thus referred to as the golden age of
microbiology.
During these years, numerous branches of
microbiology were established and the
foundations were laid for the maturing
process that has led to the modern
microbiology.

The French chemist whose experiments
on germs led to the greatest medical
breakthrough of all time.
Born on dec 27th 1822 in Dole, France.
Studied at a French school, The Ecole
Normale Superieure.
In 1848 he achieved distinction in organic
chemistry for his discovery that tartaric
acid, a four carbon compound forms two
different types of crystals.

Using microscope he successfully
separated the crystals and developed a
skill that aided his later studies of
microorganisms.
He was appointed as professor of
chemistry at the University of Lille in
Northern France in 1854.
In 1857 he developed curiosity as to why
the local wines were turning sour

 In a series of experiments he clarified the role
of yeast cells in fermentation and that the
bacteria were responsible for sour wine.
 First he removed all the traces of yeast from a
flask of grape juice and set the juice aside to
ferment and he observed that nothing
happened.
 Then he added back the yeasts and soon
found that the fermentation was proceeding
normally.

In 1857, he published a short paper on
souring by bacteria and also implied that
the microorganisms were related to human
illness and set down the foundation for the
germ theory of disease.
This theory holds that microorganisms are
responsible for infectious diseases.

 He also recommended a practical solution to
the sour wine problem.
 He suggested that grape juice be heated to
destroy all the evidence of life , after which
yeast should be added to begin fermentation.
 An alternative was to heat the wine after
fermentation , before ageing so that souring is
prevented.
 This technique was accepted and ended the
problem and was named “pasteurization”.

Pasteur’s interest in micro organisms rose
as he learned more about them.
He found bacteria in soil , water , air and
the blood of diseased victims

Extending his germ theory of disease, he
reasoned that if microorganisms were
acquiring from the environment, their
spread can be controlled.
Thus the chain of transmission could be
broken.
However many scientists stubbornly stuck
to the notion that bacteria arise
spontaneously from organic matter and the
disease is inevitable.

He wanted to prove his germ theory and
disprove the theory of spontaneous
generation and conducted a series of
experiments.
He first showed that where diseases were
rampant, the air was full of
microorganisms, but where disease was
uncommon the air was clean.

He opened flasks of nutrient rich broth to
air from the crowded city, then from the
country side and from the high mountain.
In each succeeding experiment fewer
flasks became contaminated with
microorganisms.
When he boiled the broths they remained
free of life and the critics argued that
boiling destroyed the life force which is
believed to be in the air.

Finally in a series of experiments Pasteur
silenced almost all the supporters of the
theory of spontaneous generation.
Pasteur brought an end to the long
debate on spontaneous generation.

 Pasteur then realized that he was no closer to
solve the riddle of disease.
 In the year 1865 cholera struck Paris killing
200 people a day when Pasteur attempted to
capture the responsible bacteria by filtering
the hospital air and trapping the bacteria in
cotton.
But he was unable to cultivate one
bacterium apart from the others
because he was using the broth.

Later Pasteur demonstrated that bacterial
inoculations made animals ill but could not
pin point the exact cause.
Some of his critics then claimed that a
poison or toxin in the broth was
responsible for the disease.
In an effort to help the French industry
Pasteur turned his attention to “pebrine”
the disease of silk worms

 Late in 1865, he identified a protozoan
infesting the silk worms and the mulberry
leaves fed to them.
 Next he separated the healthy silk worms
from the diseased ones and also their food.
Thus he managed to control the spread of
disease.
 It was a time of grief again as his 3rd daughter
Cecille died of typhoid in the year 1872
following which he returned to the study of
human disease

Although Pasteur failed to relate a
specific organism to a specific human
disease his work stimulated others to
investigate the nature of
microorganisms and to ponder their
association with disease

Gerhard Hansen a
Norwegian
physician identified
bacteria in the
tissues of leprosy
patients in the year
1871.

OttoObermeier the founder of
German parasitology and father of
German tropical medicine described
bacteria in the blood of relapsing fever
patients in 1873.
Another German bacterologist
Ferdinand J. Cohn discovered that
bacteria multiply by dividing into two
cells.

In England Joseph
Lister (1869)
introduced the
antiseptic technique in
surgery after being
impressed by Pasteurs
work.

This helped in the effective drop in the
morbidity and mortality due to surgical
sepsis.
His views of carbolic acid was hazardous
and cumbersome.
That was a milestone in the evolution of
antiseptic surgery ( father of antiseptic
surgery)

 A country doctor from East Prussia who
wanted to be an explorer ,was frustrated by
his inability to do anything to cure disease.
 Kochs primary interest was anthrax, a deadly
blood disease in cattle and sheep.
 In the year 1875, in his laboratory he injected
mice with the blood of diseased sheep and
cattle
 He then found that the mice developed same
symptoms as those of sheep and cattle.

Then he isolated a few rod shaped
bacteria from the blood into sterile
aqueous humor of ox’s eye.
He watched for hours as the bacilli
multiplied, formed tangles and finally
formed spores.
These spores were injected into healthy
mice and the symptoms of anthrax
developed within a few hours.

POSTULATE Experimentation
The microorganism must be present in
every case of the disease but absent
from healthy organisms.
Koch developed a staining technique
to examine human tissue. M.
tuberculosiscells could be identified
in diseased tissue
. The suspected microorganisms must be
isolated and grown in a pure culture
Koch grew M. tuberculosis in pure
culture on coagulated blood serum.
The same disease must result when the
isolated microorganism is inoculated into
a healthy host
Koch injected cells from the pure
culture of M.tuberculosis into guinea
pigs. The guinea pigs subsequently
died of tuberculosis
The same microorganism must be
isolated again from the diseased host
Koch isolated M. tuberculosis
from the dead guinea pigs and
wasable to again culture the
microbe in pure culture on

 Some microbes are obligate intracellular parasites
(like chlamydia or viruses) and are very
challenging, or even impossible, to grow on
artificial media.
 Some diseases, such as tetanus, have variable
signs and symptoms between patients.
 Some diseases, such as pneumonia & nephritis,
may be caused by a variety of microbes.
 Some pathogens, such as S. pyogenes, cause
several different diseases.
 Certain pathogens, such as HIV, cause disease in
humans only — it is unethical to purposefully infect
a human.

Following this achievement Koch
developed various staining techniques for
bacteria.
Then he happened to develop various
culture methods of bacteria.
He observed that a slice of potato
contained small masses of bacteria which
he termed “colonies”.

 Seeing that bacteria could grow and multiply
on solid surfaces, Koch added gelatin to his
broth to prepare a solid culture medium.
 He found visible colonies over the surface of
the solid medium after a day after inoculation.
 Thus he could isolate pure cultures of
bacteria and was certain that only one
species of bacterium was involved in disease.

Thus his work proved that bacteria but not
the toxins in the broth were the cause of
the disease.
This was one of the greatest achievements
in the field of microbiology.
One of the drawbacks of his gelatin culture
medium was that a few bacteria were
digesting gelatin and also at high
temperatures it gets liquified.

 Then Fannie Hesse, wife of Kochs associates
suggested the use of agar ( a sea weed
derived powder) for solidification of culture
media as she observed her mom using it for
preparing jams and jellies.
 Agar did not liquify even at high temperatures
and mixed well with almost all liquids.
 In 1881 Koch demonstrated his pure culture
techniques to the international medical
congress in London at Listers laboratory.

 Although the criteria that Koch developed for
proving a causal relationship between a
microorganism and a specific disease have been
of great importance in medical microbiology, it is
not always possible to apply them in studying
human diseases. For example, some pathogens
cannot be grown in pure culture outside the host;
because other pathogens grow only in humans,
their study would require experimentation on
people. The identification, isolation, and cloning of
genes responsible for pathogen virulence have
made possible a new molecular form of Koch’s
postulates that resolves some of these difficulties.
The emphasis is on the virulence genes present in
the infectious agent rather than on the agent itself.
The molecular postulates can be briefly
summarized as follows

 1. The virulence trait under study should be
associated much more with pathogenic strains of
the species than with nonpathogenic strains
 2. Inactivation of the gene or genes associated
with the suspected virulence trait should
substantially decrease pathogenicity.
 3. Replacement of the mutated gene with the
normal wild-type gene should fully restore
pathogenicity.
 4. The gene should be expressed at some point
during the infection and disease process.
 5. Antibodies or immune system cells directed
against the gene products should protect the host.

The molecular approach cannot always be
applied because of problems such as the
lack of an appropriate animal system. It
also is difficult to employ the molecular
postulates when the pathogen is not well
characterized genetically.

Kochs verification of germ theory was
presented in 1876 and within 2 years
Pasteur had verified the proof and went a
step ahead stating that bacteria were
temperature sensitive because chickens
did not acquire anthrax at their normal
body temperature of 42 c but did so when
they were cooled down to 37 c.

Pasteur also recovered anthrax spores
from the soil and suggested that dead
animals can be burned or buried deeply in
soil unfit for grazing.
During the course of Pasteurs study he
introduced techniques of sterilization and
developed steam sterilizer, autoclave and
hot air oven.

He also established the differing growth
needs of different bacteria.
One of Pasteurs remarkable discoveries
was made in 1880.
An accidental observation that chicken
cholera bacillus cultures left on the bench
for several weeks lost their pathogenic
ability but retained their ability to protect
the birds against subsequent infection by
them.

This observation led to the discovery of the
process of attenuation and the
development of vaccines.
He attenuated the cultures of anthrax
bacillus by incubation at high temperatures
and proved that inoculation of such
cultures in animals induced specific
protection against anthrax and was
successful by demonstrating it in a public
experiment in the year 1881.

It was Pasteur who coined the term
vaccine.
Koch in Germany in 1881 isolated the
bacillus that causes tuberculosis.
In 1884 his associate George Gaffky
cultivated the typhoid bacillus.
In the same year, another associate of his
Friedrich Loeffler isolated diphtheria
bacillus.

Emile Roux and Alexandre Yersin of
Pasteurs group had linked diphtheria to a
toxin produced in the body.
Kochs coworker Emil Von Behring
successfully treated diphtheria by injecting
antitoxin- a preparation of antibodies
obtained from animals immunized against
diphtheria for which he was awarded the
first nobel prize of physiology and
medicine.

Shibasaburo Kitasato of Japan studied
with Koch and successfully cultivated the
tetanus bacillus, an organism that grows
only in the absence of oxygen.
One of Pasteurs associates Elie
Metchinkoff a native of Ukraine in 1884
published an account of “phagocytosis”, a
defensive process in which the WBCs
engulf and destroy microorganisms.

Ernst Karl Abbe a German
physicist introduced the oil
immersion lens of the
microscope in the year
1878.
8 years later he invented
the system of lenses and
mirrors known as Abbe
condenser which
concentrates light on
objects being viewed and
makes increased
magnification feasible.

 In 1885 Pasteur successfully
immunized young Joseph
Meister against the dreaded
disease rabies . Although he
never saw the agent causing
rabies he could cultivate it in
the brain of animals and inject
the boy with bits of the brain
tissue.
 Many monetary rewards
followed after this discovery
and after immunization of 20
peasants against rabies .

 These funds helped him establish The
Pasteur Institute in Paris, one of the worlds
foremost scientific establishments.
 Pasteur presided over it till his death in 1895.
 In 1883, Robert Koch studied cholera in
Egypt and India and could isolate a comma
shaped bacillus and confirmed the suspicion
raised by John Snow that water is the key to
transmission

In 1891,he became the director of Berlins
Institute of Infectious Diseases.
He studied about malaria, plague and
sleeping sickness. But his work with
tuberculosis ultimately gained him the
nobel prize in physiology or medicine in
1905.
He died of stroke in 1910 at the age of 66.

Charles Nicolle of Pasteur Institute
proved that typhus fever was transmitted
by lice.

Albert Calmette of Pasteur Institute
developed a harmless strain of tubercle
bacillus use for immunization.

A French scientist Jules Bordet isolated
the bacillus of pertusis or whooping cough

Kochs successors Emil Von Behring and
Richard Pfeiffer isolated one of the
several organisms causing meningitis

Another coworker Paul Ehrlich a chemist
explored the mechanisms of immunity and
synthesized the “magic bullet” an arsenic
compound that would seek out and destroy
syphilis organisms in the human body.

Sir Ronald Ross an English physician
proved that mosquitoes are the vital link in
the transmission of malaria and was
awarded the nobel prize in 1902.

David Bruce showed that tse tse flies
transmit sleeping sickness.
A british scientist Almroth Wright
described opsonins, the chemical
substances that assist phagocytosis in the
body.

 William Welch isolated the gas gangrene
bacillus.
A Russian scientist Sergius Winogradsky
discovered that certain bacteria utilize
carbon dioxide to synthesize
carbohydrates similar to plants.

And many more discoveries were made
the fields of virology, mycology,
parasitology and immunology.
The advent of world war I in 1914 signalled
the end of the golden age of microbiology.

Von
Recklinghausen
(1871)
Pasteur (1880)
Observed
Staphylococci in
human pyogenic
lesions.
Obtained liquid
cultures of the
cocci from pus and
produced
abscesses by
inoculating them
into rabbits.

Sir Alexander
Ogston (Scottish
surgeon in 1880)
 Established the
causative role of the
coccus in abscesses
and other
suppurative lesions.
 Gave the name
“Staphyococcus”
 Noticed non virulent
Staphylococci on
skin surfaces.

 Rosenbach (1886)
 Kitasato (1889)
 Demonstrated a slender
bacillus with round
terminal spores in a case
of tetanus.
 Demonstrated the
etiological role of the
bacillus in tetanus and
isolated it in pure culture
and reproduced the
disease in animals by
inoculation of pure
cultures.

 Billroth (1874)
 Ogston (1881)
 First to see cocci in
chains in erysipelas
and wound infection.
 Gave the name
Streptococci.
 Isolated them from
acute abscesses.

Escherich (1885)
Friedlander (1883)
 Escherichia coli was
named after him who
was the first to
describe the colon
bacillus.
 Klebsiella
pneumoniae was first
isolated by him from
fatal cases of
pneumonia.

 Pasteur (1881) and
Sternberg (1881)
 Fraenkel and
Weichselbaum
(1886)
 First noticed them and
produced fatal
septicemia in rabbits
by inoculating human
saliva and isolated
pneumococci from the
blood of animals.
 Established the
relationship between
Pneumococci and
pneumonia

 Neisser (1879)
 Weichselbaum
(1887)
 First described N.
gonorrhea in pus in
gonorrheal patients.
 First described N.
meningtidis and
isolated it from spinal
fluid of a patient.

 Bretonneau (1826)
 Klebs (1883)
 Loeffler (1884)
 First recognised
diphtheria as a clinical
entity and called the
organism as
diphtherite.
 First observed and
described the bacillus.
 First cultivated the
bacillus.

 Roux and Yersin
(1888)
 Von Behring (1890)
 Discovered the
diphtheria exotoxin
and established its
pathogenic effect.
 First described the
exotoxin.

 Pollender (1849)
 Davaine (1850)
 First pathogenic
bacterium to be
observed under the
microscope.
 The first
communicable
disease shown to be
transmitted by
inoculating infected
blood

 Robert Koch (1876)
 Pasteur (1881)
 First bacillus to be
isolated in pure
cultures and shown to
possess spores .
 First bacterium used
for the preparation of
attenuated vaccine.

 Achalme (1891)
 Welch and Nuttall
(1892)
 First cultivated Cl.
perfringens
 Isolated from the
blood and organs of
cadaver.

 Hippocrates and
Aretaeus
 Carle and Rattone
(1884)
 Nicolaier (1884)
 Described since
ancient times.
 Transmitted the
disease to rabbits.
 Suggested that the
manifestations of the
disease were due to
a strychnine like
poison produced by
the bacillus.

 Shiga (1896)
 Eberth (1880)
 Gaffky (1884)
 Isolated Shigella from
an epidemic
dysentery in Japan.
 First observed
salmonella in
mesenteric nodes.
 First isolated from a
case of typhoid.

 Pacini (1854)
 Robert Koch(1883)
 Yersin and Kitasato
(1894)
 First observed Vibrio
cholera.
 First isolated from
cholera patients.
 Plague bacillus was
discovered
simultaneously.

 Pfeiffer (1892)  Observed
Haemophilus in the
sputum of the patients
from an influenza
pandemic but no
causal relationship
was proven later by
Smith and Andrews.

 Jules Bordet and
Gengou (1900)
 David Bruce(1886)
 Identified Bordetella
pertussis in sputum of
cases of whooping
cough and succesfully
cultivated it.
 Isolated Brucella from
the spleen of fatal
cases of malta fever.

 Robert Koch (1882)
 Hansen (1868)
 Schaudinn and
Hoffman (1905)
 Isolated the human
Tubercle bacillus.
 Discovered the lepra
bacillus .
 Discovered the
causative agent of
syphilis… Treponema
pallidum.

 Wolff and Israel
(1891)
 Warren and Marshall
(1983)
 Isolated
actinomycetes.
 Observed H.pylori in
cases of gastritis and
peptic ulcer.

 Prescott, Harley, and Klein’s Microbiology 7th
edition
 ALCAMO – Fundamentals Of Microbiology, 6th
edition.
 Ananthanarayan and Paniker’s Textbook of
Microbiology, 9th edition
 Internet

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