about bacteria and virus, diseases harmful microbes and useful microbes , microbes in sewage treatment, structure of bacteria and virus, classification of bacteria and viruses

2. Bacteria
Bacteria are microscopic single-celled
organisms that thrive in diverse environments.
They can live within soil, in the ocean and
inside the human gut.

3. Structure of Bacteria
Bacteria
composes of
cytoplasm, cell
wall,
ribosomes and
flagella.

4. Classification of bacteria
• Classification – ordering
• Nomenclature – naming
• Often immortalizes the
person
who discovered it or its
origin
– Escherichia coli 
Theodor Escherich
– coli  from colon
• Distinguishing –
identification

5. Classification of bacteria
• *Kingdom
• Phylum
• Class
• Order
• Family
• *Genus ( 1st name)
• *Species ( 2nd
name identifier)

6. Classification of bacteria
• Morphology – shape,
color, gram specificity
• Metabolism
• Molecular techniques
– Forensics, DNA
finger prints, RNA,
protein analysis

8. Species Transmission Diseases
Bacillus anthracis
Contact with sheep,
goats and horses
Inhalation or skin
penetration through
abrasions of spore-
contaminated dust
Cutaneous anthrax
Pulmonary anthrax
Gastrointestinal anthrax
Bordetella
pertussis
Contact with respiratory
droplets expelled by
infected human hosts.
Whooping cough
Complications:
Secondary bacterial pneumonia
Clostridium tetani
Spores in soil infecting
puncture wounds, severe
burns or surgery
Tetanus
Corynebacterium
diphtheriae
Respiratory droplets
Part of human flora Diphtheria
Escherichia
coli (generally)
Part of gut flora,
spreading
extraintestinally or
proliferating in the GI
tract
Urinary tract infections (UTI)
Diarrhea
Meningitis in infants
Enterotoxigenic
Escherichia
coli (ETEC)
Faecal-oral through food
and water
Direct physical contact
Traveller's diarrhea
Bacterial Diseases

9. Species Transmissions Disease
E. coli O157:H7 Reservoir in cattle Hemorrhagic colitis
Hemolytic-uremic syndrome
Francisella
tularensis
Vector-borne by
anthropods
Infected wild or domestic
animals, birds or house
pets
Tularemia
Haemophilus
influenzae
Droplet contact
Human flora of e.g.
upper respiratory tract
Bacterial meningitis
Upper respiratory tract infections
Pneumonia, bronchitis
Helicobacter
pylori
Colonizing stomach
Unclear person-to-
person transmission
Peptic ulcer
Risk factor for gastric carcinoma and
gastric B-cell lymphoma
Legionella
pneumophila
Droplet contact, from
e.g. cooling towers,
humidifiers, air
conditioners and water
distribution systems
Legionnaire's Disease
Pontiac fever
Leptospira
interrogans
Food and water
contaminated by e.g.
urine from wild or
domestic animals.
Leptospira survives for
weeks in stagnant water.
Leptospirosis

10. Species Transmission Disease
Mycobacterium
leprae
Prolonged human-
human contact, e.g.
through exudates from
skin lesions to abrasion
of other person
Leprosy (Hansen's disease)
Mycobacterium
tuberculosis Droplet contact Tuberculosis
Mycoplasma
pneumoniae
Human flora
Droplet contact Mycoplasma pneumonia
Neisseria
gonorrhoeae
Sexually transmitted
vertical in birth
Gonorrhea
Ophthalmia neonatorum
Septic arthritis
Rickettsia
rickettsii
Bite of infected wood or
dog tick Rocky mountain spotted fever
Salmonella typhi
Human-human
Faecal-oral through food
or water
Typhoid
fever type salmonellosis (dysentery,
colitis)
Shigella sonnei
Faecal-oral
Flies
Contaminated food or
water
Bacillary dysentery/Shigellosis

11. Virus

12. Classification of virus

13. Classification of viruses
Viruses were divided into six groups based on the their
nucleic acid and m-RNA production.
• 1- ds-DNA viruses.
• 2- ss-DNA viruses.
• 3- ds- RNA viruses.
• 4- ss-RNA viruses with positive strands( positive
polarity).
• 5- ss-RNA viruses with negative strands(negative
polarity).
• 6- ss-RNA viruses associated with the enzyme reverse
transcriptase.

14. Structure of virus
• All viruses contain nucleic
acid, either DNA or RNA
(but not both), and a
protein coat, which
encases the nucleic acid.
Some viruses are also
enclosed by an envelope of
fat and protein molecules.
In its infective form,
outside the cell, a virus
particle is called a virion.

15. Viral Diseases

16. Useful Microbes

18. Harmful microbes

19. Harmful microbes
• Bacteria cause lots of different types of disease,
from sore throats and food poisoning to swelling
of the brain and death of nerves in your skin!
• Some mushrooms can make you sick, even
though they look safe to eat. There are fungi that
love to make horrible itchy, scaly patches on your
skin. Other fungi love the warm, damp skin
between your toes and make your skin crack and
bleed! If fungi get inside your body, they can
cause serious problems.

20. Harmful microbes
• Viruses cause lots of different diseases, from
cold sores and warts to measles, colds and
flu! They can be very contagious - they spread
very quickly from one person to another. They
can even spread in the air, in droplets that
form when people cough or sneeze or from
surfaces like door handles and
telephones! There are very few medicines for
viruses, antibiotics don’t work on viruses.

21. Microbes in human welfare
• Microbes in Household products: A common example
is the production of curd from milk. Micro-organisms
such as Lactobacillus and others commonly called
Lactic Acid Bacteria (LAB) grow in milk and convert it to
curd. During growth, the LAB produces acids that
coagulate and partially digest the milk proteins. It also
improves its nutritional quality by increasing vitamin
B12. In our stomach too, the LAB play very beneficial
role in checking disease causing microbes.
• The dough, which is used for making bread, is
fermented by using baker’s yeast (Saccharomyces
cerevisiae).

22. Microbes in human welfare
• “Toddy”, a traditional drink of some parts of
southern India is made by fermenting sap from
palms.
• Microbes are also used to ferment fish, soya bean
and bamboo-shoots to make foods. Cheese, is
one of the oldest food items in which microbes
were used. The large holes in ‘Swiss cheese’ are
due to production of a large amount of CO2 by a
bacterium named Propionibacterium sharmanii.
The ‘Roquefort cheese’ is ripened by growing a
specific fungus on them for a particular flavour.

23. •
Microbes in Industrial products:
Production on an industrial scale requires growing microbes in
very large vessels called Fermentors.
a) Fermented Beverages:
The yeast Saccharomyces cerevisiae used for bread making and
commonly called brewer’s yeast, is used for fermenting malted cereals
and fruit juices to produce ethanol. Wine and beer are produced without
distillation whereas whisky, brandy and rum are produced by distillation of
the fermented broth.
b) Antibiotics:
Antibiotics are chemical substances, which are produced by some
microbes and can kill or retard the growth of other disease causing
microbes.
Pencillin was the first antibiotic to be discovered and it was a
chance discovery. Alexander Fleming while working on Staphylococci
bacteria, once observed a mould growing in one of his unwashed culture
plates around which Staphylococci could not grow. He found out that it
was due to a chemical produced by the mould and he named it Pencillin
after the mould Pencillium notatum. Later, Ernest Chain and Howard
Florey made its full potential effective antibiotic.

24. • Enzymes:
Lipase – used in laundry detergents
• Pectinase and protease – used in bottled juices
• Streptokinase (Streptococcus bacterium) – used
as clot buster (to remove clots)
•
Bioactive molecules: Cyclosporin A (Trichoderma
polysporum fungi) – used as immunosuppressive
agent (for organ transplant patients).
• Statins (Monascus purpureus yeast) – used as
blood cholesterol lowering agents.

25. Role of bacteria and viruses in sewage
treatment
• Microbes in Sewage Treatment:
Treatment of waste waster is done by heterotrophic
microbes naturally present in the sewage. This treatment is
carried out in two stages;
Primary treatment / Physical treatment: It involves
physical removal of particles from the sewage through
filtration and sedimentation.
Sequential filtration – to remove floating debris
• Sedimentation – to remove grit (soil and small pebbles)
• All solids that settle form the primary sludge, and the
supernatant forms the effluent. The effluent from the primary
settling tank is taken for secondary treatment.

26. Role of bacteria and viruses in sewage
treatment
• Secondary treatment / Biological treatment: The
primary effluent is passed into large aeration tanks, this
allows vigorous growth of aerobic microbes into
flocs. While growing, these microbes consume the major
part of the organic matter in the effluent. This
significantly reduces the BOD (biochemical oxygen
demand) of the effluent. BOD is a measure of the organic
matter present in the water. The greater the BOD of
waste water, more is its polluting potential.
• Once the BOD of sewage water is reduced significantly,
the effluent is then passed into a settling tank where the
bacterial ‘flocs’ are allowed to sediment. This sediment is
called Activated sludge.

27. Role of bacteria and viruses in sewage
treatment
• A small part of this sludge is pumped back into
the aeration tank to serve as the inoculum.
• The remaining major part of the sludge is
pumped into large tanks called anaerobic sludge
digesters.
• During this digestion, bacteria produce a mixture
of gases such as methane, hydrogen sulphide and
carbon dioxide. These gases form biogas.
• The effluent from the secondary treatment plant
is generally released into natural water bodies
like rivers and streams.

28. Images of bacteria

29. Images of virus

30. -Kushwanth.P