general Bacteriology aconcise.pdf

General bacteriology
a concise course
By Mohamed Alashram
General Bacteriology aconcise course Review1 Mo.Alashram
Illustrated
Abbreviated

Why this book
Review2
simplified
General Bacteriology aconcise course
colored
contain Basic principals
Mo.Alashram

General Bacteriology
Table of •
contents
Content
History
Bacterial cell morphology
Bacterial cell morphology
Bacterial nutrition
Bacterial product
Bacterial pathogenicity and virulence
Bacterial growth
Diphtheria learn us too much about epidemiology
Methods of identifying unknown bacteria

Concise
course
=
short
journey
Learn
+
enjoy

We fight unseen enemy
we use and have
benefit of unseen fried
only. With some
knowledge and
technique we can feal
its presence or absence

Micro small Logos science Bios life
Science dealing
with minute
microorganism
unseen with
naked eyes
micro/bio/logy
Introduction

Microbiology is extensive
science
Necessity study to study different
microorganisms
Microbiology is subdivided into

Discoveries change the world
Koch discover TB
Pasteur discover pasteurization
It was only in 1983 that the HIV
virus was isolated and identified by
researchers at the Pasteur Institute
in France.

•

In fact the relationship between man and microorganism
start as early as beginning of his existence on earth
he observed the putrefaction of carcass of animals birds
himself
Putrefaction
the process of
decay or rotting
in a body or other
organic matter

Ancient Egyptian could stop putrefaction of carcasses of their kings and preserve their holly mummies
for several thousands of years by famous Egyptian art and science of Embalming

Although ancient man did not know the real microbial cuase
He notice sugar fermentation
• He experienced several bacterial
viral and prasitic diseases
• He tries o treat b
• Herbes
• magic
Made alcoholic beverage
• He made bread
• He made cheese
• He made vingar

Life itslf when seen in small
creature like worms and insects
was explained
by spontaneous generation
Aristotle 384-322 BC
• As a chemical interaction between
organic matter water and air
Man tried to understand the usual changes resulting from
microbial action as purely chemical process

Only in 1668 redi an italian scientist
douted in theory and in simple experiment could prove that maggot are
not sponteously created from dead matter but they were the hatching
larvae from eggs laid down by flies on piece of meat
• In his 2nd experiment Redi used
gause to coverhalf the jar to allow
air but not flies
• Maggot fly larvae would apear on
uncovered meatbut not on the
meat in sealed jar

R.hook 1665
• Discover compound microscope
• He was able to see individual cells
• Of living creatures
A.V. leeuwenhook 1773
• With his single lens microscope with
magnification power 300x he
• Discovered the microbial world
• He describe and draw microorganisms
for the first time
• He published his discovery in journal
of royal society of London 1683
Only in 17 century
two major achievement regarding the discovery of microscope

LOUIS PASTEUR Robert Koch
,
Joseph Lister
pasteurization
Koch’s Postulates
of Disease
Transmission
sterilization
pioneers

History of microbiology

lister

KOCH’S POSTULATES
1. The microorganism should be constantly associated with the
lesion.
constantly associated with the lesion
2. It should be possible to isolate the organism in pure culture from
the lesion of the disease.
3. The same disease must result when the isolated microorganism is
inoculated into suitable laboratory animal.
4. It should be possible to re-isolate the organism in pure culture
from the lesions produced in the experimental animals.
5. Antibody to the causative organism should be demonstrable in
patient’s serum

Do magic first
Antimicrobial prontosil
Fleming penicillin discovery

Louis Pasteur
He had proposed
the principles of fermentation for preservation of food
• Introduced sterilization techniques
developed steam sterilizer, hot air oven and autoclave
•
Described method of pasteurization of milk

COCCI spherical STAPH AURAS
Bacterial morphology
BACILLI
RODE
SHAPE BACILLUS ANTHRACIS
FILAMENTOUS
COMMA SHAPE
SPIRAL
General Bacteriology aconcise course
A
C
T
I

NOMYCES
VIBRIO
CAMPYLOBAC
TER
HELICOBACT
ER
Review23
Mo.Alashram

Culture and stain

• 1micron in
diameter
Bacillus anthracis
Blood cell
• 7micron in diameter

Bacterial cell size
Bacillus anthracis 3- 8 micron - *1-1.2 microcracks
staph auras 0.8- 1 micron smallest known famous
rickettsia prowazekii’s smallest
vaccinia virus 0.15- 0.25 micron
Influenzae 1*0.3 micron

Bacterial anatomy

Bacterial structure
• Capsule
• Flagella
• Fimbriae
• Cell wall
• Polysaccharide k antigen
• Motion H antigen flagellar
• antigen
• Attachment
• Give the shape of bacteria

Cell wall structure
Semirigid structure responsible for characteristic shape of
bacteria
Chemically macromolecular network called peptidoglycan
It is thick in Gam positive thin Gram negative

Cell wall structure
Semirigid structure responsible for
characteristic shape of bacteria
Chemically macromolecular network
called peptidoglycan
It is thick in Gam positive thin
Gram negative

Function of cell wall
Give bacteria characteristic shape
Protect cytoplasm
Determine gram staining nature
Gram positive
Game negative
Penicillin kills bacteria by inhibiting cell wall formation
Mycoplasmas has no cell wall so it is penicillin resistant

Gram stain
Gram positive
• Crystal violet complex with iodine
• Trapped in peptidoglycan cannot
be removed by decolorization
Gram negative
• Violet stain initially retained by
lipoprotein layer
• Decolorization dissolve lipoprotein
• Counterstaining result in staining
of decolorized bacteria with red
stain

Cell membrane living highly active thin double layered
internal to cell wall
chemically composed
of 60% protein 40% phospholipid
function of cell membrane
selective barrier selective
permeability some molecule pass other not
site for active metabolic process
site for electron transport system
has folds mesosomes increase total surface size

Damage to cell membrane
leads to bacterial death
Alcohol
disinfectant like
quaternary ammonium compound
antibiotics
polymyxin
nystatin
Damage to the cell membrane disturbs the
state of cell electrolytes, e.g. calcium, which
when constantly increased, induces
apoptosis. ... Ribosome damage: Damage to
ribosomal and cellular proteins such as
protein misfolding, Leading to apoptotic
enzyme activation.

▪
Chemotrophic bacteria
Require energy
From chemical substances
▪ Phototrophic bacteria
▪ require energy from sunlight
Typesofbacteria
according to
surceofenergy
Physiology of bacteria

▪ Heterotrophic bacteria
▪ Cannot use only co2 main source of carbon
▪ but require organic carbon
▪ Autotrophic bacteria
▪ Can utilize co2 as main source of carbon
Typesofbacteria
according to
sourceofcarbon

sporulation
▪ Family Bacillaceae change typical vegetative form
▪ Into resistance spore forming
▪ Factor resulting in pore forming sporogeneses
▪ Exhaustion of nutrient
▪ Dryness
▪ Change of Ph
▪ accumulation of toxic substances
Endospore formation

Typesofspores

Bacterial product
Toxin
Pigmen pseudomonas aeruginosa
Light fluorescent bacteria living in decaying matter
Heat
Enzymes
Miscellaneous indole diagnostic in biochemical test
Bacitracin used as antibiotic

Bacterial toxin
Exotoxin Endotoxin
Gram positive •
Metabolic product has specific effect •
Soluble body fluid •
Cytotoxin kill host cell •
Neurotoxin interfere with nerve impulse •
Enterotoxin botulism •
tetanus diphtheria •
Gram negative cell wall lipid portion of •
lipopolysaccharide
Exert general effort when bacteria die •
Its effect may be shock •
Clots obstruct blood vessels •
Typhoid fever •

Enzymes
exoenzymes produced outside the bacterial cell
endoenzymes produced inside the bacterial cell
enzymes serve as a catalyst specific e.g. sucrase
substrate is sucrose hydrolysis of sucrose to glucose fructose these
reaction byproduct used in identification characterization of bacteria
exoenzymes in some bacteria increase its virulence e.g. Hemolysin
enzyme grouped into classes oxidases dehydrogenases

Bacterialpathogenicityandvirulence
pathogenicity
Infectivity
Virulence
Ability to produce disease
ability to induce infection
degree of pathogenicity

▪ Toxigenicity ability to produce exo or endo toxin
▪ Most important component of virulence
▪ Invasiveness ability to invade the tissue sporulated
bacteria like Bacillus anthracis
▪ Communicability ability of microorganism to establish
himself in tissue
▪
Componentof
bacterial
virulence

▪ Rough form
▪ Only bacillus anthracic is more virulent when is rough
▪ Smooth form
▪ Most colonies are virulent when smooth
Physiological
state of the
bacterium

n
Typesofbacterialinfection
local
generalized
▪ According to transmissio
▪ Droplet
▪ Dust
▪ Food born
▪ Insect born
▪ According to severity
▪ Per acute
▪ Acute
▪ Subacute
▪ Chorionic
▪ latent

▪Bacteremia viable bacteria
present in blood
▪Septicemia blood poisoning
presence of toxin and bacteria
in blood stream
▪Toxemia presence of bacterial
toxins in blood
▪Pyemia bus forming bacteria
circulating in blood stream
Types of
generalized
infection

Diphtheria
a wild microorganism

In 1735, a diphtheria epidemic swept
through New England

In 1856 , Victor
Fourgeaud described an
epidemic of diphtheria in
California.

In 1878, Queen Victoria's
daughter Princess Alice and her
family became infected with
diphtheria,
causing two deaths, Princess
Marie of Hesse and by
Rhine and Princess Alice herself

Diphtheria
=
membrane
Pierre-Bretonneau (3 April 1778 –
18 February 1862) was
a French medical doctor.

n 1883, Edwin Klebs identified
the bacterium causing
diphtheriaand named it Klebs–
Loeffler bacterium.
Friedrich Loeffler was the first person to
cultivate C. diphtheriae in 1884] He
used Koch's postulates to prove
association between C. diphtheriae and
diphtheria. He also showed that the
bacillus produces an exotoxin.
n 1888, Emile
Roux and Alexandre
Yersin showed that a substance
produced by C.
diphtheriae caused symptoms
of diphtheria in animals

In 1890, Habsburg
Kitasato and Emil von
Behring immunized guinea pigs
with heat-treated diphtheria toxin
They also immunized goats and
horses in the same way and
showed that an "antitoxin" made
from serum of immunized animals
could cure the disease in non-
immunized animals. Behring used
this antitoxin (now known to
consist of antibodies that
neutralize the toxin produced by C.

diphtheriae for human trials in
1891, but they were
unsuccessful.
Successful treatment of human
patients with horse-derived
antitoxin began in 1894, after
production and quantification of
antitoxin had been optimized
Behring won the first Nobel
Prize in medicine in 1901 for his
work on diphtheria

toxin
3 parts
attachment
invading
prevent protein synthesis

cytotoxic
effect only appear after
committing the crime

Antiserum prepared in horse

Ab interfere with toxin make it
inactive

Diphtheria
a wild microorganism

Diphtheria
=
membrane

‫لوفلر‬
‫و‬
‫ورو‬
Roux
and
Loffler
Description isolation

toxin
3 parts
attachment
invading
prevent protein synthesis

cytotoxic
effect only appear after
committing the crime

Antiserum prepared in horse

Ab interfere with toxin make it
inactive

Methods for identifying unknown bacteria
Identification unknown bacteria one of the
most
important task of microbiologist

Morphological examination
shape size arrangement

presence of capsules spores
metachromatic granules

shape under dark field microscope

motility of microorganism

Gram stain

Zeal Nelsen stain

Colonial morphology on solid media
shape size color margin consistency

Growth on broth media

Growth on blood agar

Biochemical identification
depend on presence of different enzymes in
different bacteria
addition of different substrate and indicator the
principal
the principal enzyme epicist or not

Oxidase
catalase
coagulase
sugar fermentation test
litmus milk
nitrate
urease
gelatin
IMVIC
Triple sugar iron agar

Animal inoculation

Serological identification

Phage typing

Molecular methods

general Bacteriology aconcise.pdf

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