Related to econic decision making process and how much is your responsibility in decision making

1. Unit. 1
Introduction to Microbiology
Definition:Microbiology is the branch of science that deals
with the study of micro organisms.
• Microorganisms are the living things which cannot be
seen with naked eyes but can be seen with the help of
microscope.
• Bacteriology ------- The study of bacteria
• Virology ---------- The study of viruses
• Protozology -------- The study of protozoa
• Immunology ------- The study of immunity
• Mycology ----------- The study of fungi
• Phycology ---------- The study of Algae

2. Terminology
• Pathogen: An organism which causes disease is called
pathogen.
• Parasite: An organism that lives in or on another
species or creature and obtains food and shelter
without benefiting but rather harming the host.
• Saprophyte: An organism that lives on or derives its
food from dead organic matter. eg Fungi
• Normal flora: The microbes that live in or on another
creature and benefiting each other in normal
conditions.
• Vector: An animal usually an arthropode such as
insect or tick that transfers a pathogen to a person. 1)
Mechanical vector and 2) Biological Vector.

3. • Carrier: A carrier is an infected person or animal who
does not have apparent clinical disease but is a
potential source of infection to others.
• Infection: The entry of microorganism in the body is
known as infection.
• Incubation period: The period of proliferation of
microorganisms to show sign and symptoms after
their entry in a body is known as incubation period.
• Prodromal period: It is the interval between the
onset of symptoms of an infectious disease and the
appearance of characteristic manifestations.
• Prognosis: The prediction of the course of a disease.

4. • Epidemiology: The study of occurrence of disease,
how, when and where it occurs and how it is
transmitted.
• Epidemic disease: An unusual sudden onset of a
disease which breaks out in a region of a country. eg.
Cholera, or any other disease broken out
• Endemic disease: A disease which is usually found
in an area in a country. eg, typhoid, etc
• Pandemic disease: An epidemic disease that occurs
worldwide.
• Sporadic disease: A disease which is found here
and there at intervals. eg. T.B, etc

5. • Isolation: separation of infected persons for a
period of communicability of the disease.
Quarantine: limitation of the movement of
apparently well person or animal who has
been exposed to the infectious disease for a
duration of the maximum incubationperiod of
the disease.
• Inflammation: The response of body to
infection or injury which is characterized by
swelling, heat, redness and pain.

6. • Pathogenicity: The ability of an organism to cause
disease.
• Virulence: The degree or intensity level of a
pathogen.
• Toxin: A poisonous substance produced by a living
organism.
• Toxicant: A poisonous substance prepared by man.
• Antigen: Any substance usually made up of protein
that stimulates the immune response.
• Antibody: A protein that is formed as a result of the
immune response to an antigen.
• Sterilization: The process by which all forms
(vegetative and non-vegetative) of life is killed.

7. • Bactericide: A substance or agent that kills
bacteria.
• Pasteurization: This is the method of
temperature treatment at 63 C for 30 minutes to
make it free from specific germs.
• Disinfectant: An agent that kills microorganisms
by applying to inanimate (non living) objects.
• Antiseptic:An agent that kills microorganisms by
applying to living things.
• Vaccine: Attenuated or killed microbes or
inactivated toxins used to induce immunity.

8. • Vaccination: The process of inducing immunity by
administrating a vaccine.
• Fomites: Inanimate object or material used by an
infected patient, which may transfer the infection to
another person by coming in contact. For example,
Lenin, clothes and other utensils.
• Eukaryotic Cell: A complete cell having a well defined
nucleus and other membranous structures. eg.
Multicellular(like animal and higher plant cells) and
unicellular (like protozones).
• Prokaryotic Cell: An incomplete cell having no well
defined nucleus and other membranous structures.
They are always unicellular. eg. Bacterial cell

9. • Bacteria: They are prokaryotic microorganisms
which can’t be seen with naked eyes.
• Virus: A minute microorganism which shows the
characteristics of both living and non living things.
It is an obligatory parasite.
• Protozoa: Microscopic single-celled eukaryotic
microbes. Some are pathogenic and some are not.
• Mutation: A sudden change in the genetic make
up of a cell is called mutation.

10. IMPORTANCE OF MICROBIOLOGY FOR
NURSES.
Microbiology is very important and useful and it
enables the nurses to:
1. Know the nature and behavior of microorganisms
in relation to infectious diseases.
2. Know the pathogencity and virulence of different
microorganisms
3. Know the process and purposes of sterilization to
prevent communicable diseases.
4. Know the importance of vaccine and other
preventive measures against various diseases.

11. Continue
5. Use safe and aseptic techniques while handling
patients.
6. Minimize the patients’ stay in hospital by preventing
cross and nosocomial infection.
7. Be familiar with the effects of microbes on the
environment.
8. Gain the knowledge of environmental hygiene and
sanitation.
9. Create awareness in community to use safe food and
water.
10. Help in generalizing health.
11. Help in minimizing morbidity and mortality rate.

12. Short History and some Contributions
• 1665. Hook—First observation of cell
• 1673. Van Leeuwenhoek—First observation of live
microorganisms
• 1735. Linnaeus—Nomenclature of organisms
• 1798. Jenner—First Vaccine
• 1857. Pasture—Fermentation
• 1861. Pasture—Disproved spontaneousgeneration
• 1864. Pasture—Pasturization
• 1867. Lister—Aseptic surgery
• 1876. Koch—Germ theory of disease
• 1881. Koch—Pure culture
• 1882. Koch—Mycobacterium Tuberculosis
• 1883. Koch—Vibrio cholerae
• 1928. Fleming—Penicillin

13. Francesco Redi
• F. Redi put forwarded his observation and
experiments in 1664.
• Experiment:used three varieties of jars as:
• a. Covered jar---air sealed
• b. Gauze-covered jar
• c. Uncovered jar
• What were his Observations?
• Biogenesis vs. Abiogenesis

14. Koch’s Postulate
Koch’s Four Postulates are:
1. The same pathogen must be present in every
case of the same disease.
2. The pathogen must be isolated from the diseased host
and grown in pure culture.
3. The pathogen from the pure culture must cause the
disease when it is inoculated into a healthy,
susceptible laboratory animal.
4. The pathogen must be isolated from the inoculated
animal and must be shown to the original organism.

15. Eukaryotic and Prokaryotic Cells
Eukaryotic Cell
• They have all the membranous structures and well
defined nucleus enveloped by nuclear membrane.
• Eukaryotic cells are larger and more complex than
prokaryotic cells.
Properties:
• All organelles are membrane-bound
• Complex genome organization
• Large genome size
• Large amount of regulatory DNA
– To control gene expression
• Unicellular or multicellular

16. Eurocyritic Cell

17. Prokyratic
• Prokaryotic cells are smaller and simpler having
no membrane bounded structures.
For example, Bacteria.
Properties:
• Unicellular
• No membrane bound organelles
• Simple genome organization
• Between 500 and 4000 genes
• Great degree of diversity
• They mostly contain a complex substance in their
cell wall called peptidoglycan.

18. Prokyratic Cell

19. Distinguish between Eurocyritic and
Prokyratic
Character Prokaryotic cell Eukaryotic cell
Size Small (usually
<2 µm in
diameter
larger (usually 2 to>100
µm in diameter
Nuclear
membrane
Absent Present
Nucleolus Absent Present
Membranou
s structures
Absent Present
DNA Single and
Circular
Multiple and almost
linear
Cell division Amitosis
(binary fission)
Amitosis, Mitosis,
Meiosis

20. Virus
• Viruses may be defined as acellular organisms whose genomes
consist of nucleic acid, and which obligately replicate inside host
cells using host metabolic machinery.
• Size: 20 ---- 14,000 nm in length.
• Virues Properties
• Infectious – transmissible horizontally or vertically
• Obligatory Intracellular – requires a living cell
• Nucleic acid –Either DNA or RNA, but not both
• DNA and RNA – Any of them may be double-stranded or single-
stranded
• Capsid – Most have protein coat called Capsid
• Lipid envelope---May or may not present
• No Metabolic machinery – No metabolic (ATP generating) and
biosynthetic (Protein synthesizing) enzymes but use that of the
host.

21. DNA and RNA Viruses
• Polio virus
• Rhabdovirus
• Mumps virus
• Measles virus
• HIV
• Influenza virus
• Hep C virus
• Rubella virus
• Smallpox virus
• Herpesviruses
• Hepatitis B virus
• Papilomavirus
(wart virus)
RNA Virus
DNA Virus

22. Shapes of Viruses
• Spherical
• Helical
• Polyhedral
• Rod-shaped
• Brick-shaped
• Tadpole-shaped
• Bullet-shaped

23. Basic nutritional requirements of
microorganisms.
• Nutrients: are substancesthat are used to supply energy.
- Nutrients are used in biosynthesis and energy production and
requires for growth.
- Nutrients are basically classified into two types
- 1.Macronutrients. 2. Micronutrients
Macronutrients:
• These are Required by microorganisms in large amounts and
constitute95% of cell dry weight.
C, H, O, N, S, P
They are componentsof carbohydrates, lipids, proteins, and nucleic
acids.

24. Carbon
Microorganisms use carbon as an essential nutrient. It
constitutes about 50% of the dry weight of a bacterial cell.
Two major sources of carbon are organic and inorganic
compounds.
Carbon dioxide is inorganic source of carbon
Oxygen:
Oxygen is very important for life but, however, there are
some exceptions for some bacteria.
The bacteria which can live only in the presence of
molecular oxygen are called strict or obligate aerobes
(e.g, Mycobacterium tuberculosis) and those which can
grow only in the absence of oxygen are called strict
anaerobes (e.g, Clostridium tetani)
Some of the bacteria that can live in both conditions are
called facultative anaerobes. (e.g, E. coli)

25. • Nitrogen
Nitrogen is a major constituent of protein, nucleic
acid, and other molecules of microorganisms. It is,
therefore, very important.
A typical bacterial cell is composed of 12% of nitrogen
by its dry weight.
Microorganismsobtain nitrogen from organic and
inorganic sources.
Organic sources include amino acids and other
organic nitrogen containing compound.
Inorganic sources include atmospheric nitrogen,
nitrate and ammonia etc.

26. • Sulfur
Sulfur is an essential constituent of proteins. It is
primarily found in sulfur-containing amino acids like
cysteine and methionine. Some bacteria use H2S
and sulfides as a source of sulfur.
• Phosphorous
Phosphorousis a constituent of nucleic acid,
phospholipids,nucleotides, and ATP etc.
The common sources of phosphorous for bacteria are
phosphate salts.

27. • Micronurients.
• In nature, micronutrients are ubiquitous and probably
do not usually limit growth.
• Micronutrients are normally a part of enzymes and
cofactors, and they aid in the catalysis of reactions and
maintenance of protein structure.
Vitamins:
• Folic acid (B9) used as amino acid metabolism
(transamination).
• Niacin (nicotinic acid) as precursor of NAD.
• Riboflavin (B2) as precursor of FAD.
• Cyanocobalamin (B12) aids in molecular
rearrangements.

28. Minerals:
• Potassium (K ) is required for activity by a number of
enzymes, including some of those involved in protein
synthesis.
• Calcium (Ca), among other functions, contributes to the
heat resistance of bacterial endospores.
• Magnesium (Mg) serves as a cofactor for many
enzymes, complexes with ATP, and stabilizes ribosomes
and cell membranes.
• Iron (Fe) is a part of cytochromes and a cofactor for
enzymes and electron carrying proteins.
• Cobalt (Co) is a component of vitamin B12
• Molybdenum (Mo) is required for nitrogen fixation,

29. • Water
Water is essential for cellular activities. It
constitutes 70-90% of the weight of a cell.
Water is a universal solvent and it dissolves
many chemical substances including nutrients
to make them readily available for the
absorptionby microorganisms.

30. Nutritional Types of Microorganisms
• Carbon Source:
Microorganisms are classified into two groups on the basis of
sources of carbon as autotrophs and hetrotrophs.
Autotrophs are the microorganisms which derive carbon from
inorganic compounds like CO2.
Hetrotrophs are the microorganisms which derive carbon from
different organic compounds like sugar, alcohol etc.
• Energy Source:
Microorganisms depend upon different sources of energy. The
organisms which depend on sunlight as a major source of
energy are called phototrophs. Other organisms which use
chemicals as a source of energy are called chemotrophs.
Autotrophs may either use sunlight or chemical compouds as
energy source; they are called photoautotrophs and
chemoautotrophs respectively.

31. Morphology Based Classification
Three principal shapes of bacteria are:
• Coccus: (Round shape)
• Bacillus: (Rod shape)
• Spirillum: (Curved or twisted rod)

32. • They may form associations in the form of two cocci
(diplococcus), chains (streptococcus), clusters
(staphyllococcus), tetrads, and sarcina as shown
below.