Introduction of Microbiology

3. Microbiology
• Microbiology is the study of living things so small that they
cannot be seen with the naked eye.
• Microbiology
• From Greek word
• Mīkros = “small”
• Bios = “life”
• Antonie van Leeuwenhoek (Father of microbiology)
Microorganism
• Microorganisms are microscopic organism that exists as
single cells or clusters.
• It had been on earth for some 4000 millions years
• 5 × 1030 microbial cells exist on earth

4. Branches of microbiology
• Bacteriology: the study of bacteria
• Mycology: the study of fungi
• Protozoology: the study of protozoa
• Phycology: the study of algae
• Parasitology: the study of parasites
• Virology: the study of virology
• Nematology: the study of nematodes

5. Branches of microbiology
• Microbial physiology (growth, metabolism and structure)
• Microbial ecology
• Microbial genetics (gene organized and regulates)
• Microbial taxonomy (classification)
• Molecular microbiology (molecular principles)
• Epidemiology and public health microbiology (spread and
control of diseases)
• Food microbiology (foods products and drinks)
• Agricultural and veterinary microbiology (increase yield and,
control pest and diseases)
• Environmental microbiology (beneficial and harmful effects)

6. Why we need to study microbiology?
• Synthesis of drugs, hormones and enzymes
• Bioremediation (Degrade organic materials and detoxify
pollutants)
• Photosynthesis and decomposition
• Human use of microorganism (learn and excel in knowing
information about microorganisms, their diseases, treatment and
preventive measures)
• Infectious diseases

7. Basic terminology
 Abscess: A classic host response to bacterial infection
 Acidophiles: Bacteria that prefer acidic condition
 Alkaliphile: Optimum external higher pH for growth
 Antibiotic: Microbial produced substances that has
antimicrobial properties
 Antibody: A serum protein produced in response to an antigen
in which has the property of combining specifically with that
antigen
 Antiseptic: Chemical agent for disinfection that is mild enough
to used on human skin or tissues

8.  Antibiotic resistance: Ability of bacteria to withstand against
the killing effect of antimicrobial agents
 Anaerobe: Can survive and proliferate in the absence of oxygen
 Antigen: Molecule which is able to react specifically with
antibody
 Aseptic: Absence of infectious microorganisms
 Attenuated: Organism whose pathogenicity has greatly reduced
 Biofilm: Complex system of microorganism and their
surrounding polysaccharide matrix
 Budding: A mode of vegetative reproduction
 Capsule: A loose, gel like structure on the surface of some
bacteria

9.  Cellular immunity: T cell dependent host response to bacteria
 Chemotherapy: Use of drug or other chemical substance for the
treatment of disease
 Contamination: Presence of microorganism on objects, in the
environment, or in samples
 Communicable disease: Infectious disease that is capable of
spreading from person to person
 Commensalism: Symbiotic relationship in which one species
benefits and the other is unharmed
 Disinfection: Elimination or inhibition of pathogenic
microorganisms in or on object
 Endemic: Disease that occurs commonly all the year round

10.  Endogenous: Originating or produced within and organism or
one of its part
 Endospore: Highly resistance spore found within certain
bacteria
 Endotoxin: Lipopolysaccharide compound of the outer
membrane of gram-negative bacteria
 Epidemiology: Study of distribution and determinants of
diseases in populations
 Etiology: Cause or origin or a disease
 Epizootic: Outbreaks occurring in animal population
 Exogenous: Originating outside an organism, infection can be
exogenous or endogenous origin

11.  Facultative anaerobe: An organism which can grow in the
absence of oxygen, but utilized when available
 Fermentation: Metabolic process where by microbes gain
energy from the breakdown and assimilations of organic and
inorganic nutrients
 Fission: Divide at center of the cell by forming a cell septum
that constricts mother cells into two equal-size daughters
 Flagellum: Organelle of bacterium motility
 Food-born diseases: illness resulting from the ingestion of
harmful products in food
 Food poisoning: A condition that occurs after ingesting
preformed toxin

12.  Gastritis: Inflammation of stomach
 Generation time: The time taken for population of cells to
double in the time under specific conditions
 Genome: A collection of genetic material and genes of the
organism
 Genome replication: The synthesis of multiple copies of a virus
genome
 Growth medium: An aqueous solution (may be solidified with
agar) containing all the nutrients necessary for microbial growth
 Growth optimum: The condition at which an organism grows
fastest
 Hemolysis: The lysis of RBC

13.  Halophile: Organism that requires NaCl for growth
 Host: Organism affected by pathogen
 Hypha (pl. Hyphae): Single filament of mycelium
 Incidence: Number of people developing a specified disease or
becoming infected at a specified period of time
 Infection: Invasion of host organism by microorganism
 Infectious disease: Illness caused by a pathogen, which invades
body tissue and cause damage
 Infectious agent: Any bacterium, virus, protozoan, prion or
other agent that can cause infection or disease in a human,
animal or other host.
 Inoculum: Term given to the cells used to seed a new culture

14.  In vivo: Procedures performed inside of the living organism
 In vitro: Procedures performed outside of the living organism
 Immunogenicity: Capacity to elicit adaptive immunity against
pathogen
 Life cycle: The stage or successive stages in the growth and
development of an organism
 Lyophilization: The process of simultaneously freezing and
drying materials under a vacuum
 Mode of infection: Method or pathway used by pathogen to
invade host
 Mycelium: A tangled mass of branching hyphae
 Mycosis: Disease caused by a fungus

15.  Neutrophil: Microbial species that grows best in the neutral
range of external pH, generally pH 6.8
 Nosocomial infections: Infection that are acquired in hospitals
 Normal flora: Population of microbes that normally reside in
the host
 Nutrient: An organic or inorganic compound that is used as by
microorganism
 Nucleoid: Term for the bacterium chromosomes
 Obligate anaerobe: An organism that is incapable of growth in
the presence of oxygen
 Opportunistic: Causing disease in patients with impaired
immunity

16.  Pandemic: It is an epidemic that affects all or most countries in
the world at the same time
 Parasite: Organism that lives on or in another organism,
benefited from it
 Paronychia: An infection involving the folds of tissue
surrounding the nail
 Pasteurization: A mild heating used to destroy pathogens and
spoilage organisms present in the food and drink
 Pathogenicity: Ability of pathogen to cause disease
 Pathogen: An organism capable of invading the body and
causing disease
 Petri dish: Standard vessel comprises a circular dish with an
average overlapping dish

17.  Phagocytosis: Ingestion and digestion of particulate matter by
cell
 Plague: Clearer areas in a lawn of bacteria or in a monolayer of
cultured cells caused by the cytopathic effects of virus infection
 Plasmid: An autonomous DNA molecule capable of replicating
itself independently
 Pleomorphic: Lacking a regular shape, no cell wall
 Prevalence: Frequency of a diseased in a population
 Protoplast: Cell that has had cell wall removed
 Portal of entry: Site at which the pathogen enters the host and
establishes the primary infection
 Protozoa: A group of single celled eukaryotes with certain
animal like characteristics

18.  Psychrophile: An organism which can grow at the optimum
temperature of 15 ºC or lower and a maximum at temperature of 20
ºC
 Pure culture: Culture containing one type of organism which is free
from contaminant
 Redox potential: Measure of the thermodynamic tendency of an ion
or molecule to accept or donate one or more electrons
 Resolution: Capacity of an instrument to discern detail
 Saprophyte/Saprobe: An organism that feeds on dead and decaying
organism materials
 Sepsis: A serious condition resulting from the presence of harmful
microorganisms in the blood or other tissues and the body’s response
to their presence, potentially leading to the malfunctioning of various
organs, shock, and death.

19.  Septum: A partition that separates a cell into two compartments
 Sporulation: Process by which the spores are formed from
vegetatively growing bacteria due to nutrient depletion
 Starvation: An environmental condition in which bacteria do
not grow at all due to the lack of an essential nutrient
 Sterilization: The process by which all microorganisms present
on or in it are destroyed or removed
 Systemic infection: An infection that extends to involve internal
organ or tissues
 Taxonomy: Science of classifying living organism
 Toxin: A molecule that cause pathogenic changes to the host
cells that may result in disease

20.  Taxoid: A toxin, which has been treated so as to inactivate its
toxicity but which is still capable of including immunity to the
active toxin
 Vaccine: A preparation of dead or inactivated living pathogens
or their products used to provide protective immunity
 Vaccination: It is a practice of using modified (killed or
attenuated) microorganisms, or proteins, to induced immunity to
a particular disease without actually causing disease
 Vector: It’s a living creature that can transmit infection from one
host to another
 Virion: Extra cellular virus particle, these particles may be only
nucleoprotein or the nucleoprotein may be surrounding by an
envelope consisting of lipid and protein

21.  Virulence: Disease-causing properties of pathogenic species
 Virus replication: Synthesis of new virus particles includes
both replication of the genome and assembly of virus particles
 Viruses: Submicroscopic entities, composed of nucleic acid and
protein, capable of being introduced into specific living cells and
reproducing inside such cells
 Zoonosis: An infection or infectious disease of vertebrate
animals that is transmissible under neutral conditions to humans
 Zoospore: A free living and flagellated reproductive structure of
fungi

22. • Microbiology is the science which covers the various information
regarding infection, host system and control methods.
1. Nosocomial infections (also known as hospital
infection):
 Need to know information about patients susceptibility
 Most causative agents are their environments and
control methods

23. 2. Immunization
 We should know basic history of immunization
 Vaccine types: attenuated, inactivated, sub unit and toxic
vaccines
 Safety issues and risk
3. Immune response
 Basic information about non-specific and specific defense
of host
 Non-specific– Skin, mucous membrane, chemicals,
Phagocytosis, interferons, inflammation, fever
 Specific – Lymphocytes, Antibodies

24. 4. Specific immune response and specific lab techniques
 Information about microbial antigens, different classes of
antibodies and their general role
 General information about agglutination and precipitation
reactions in serological test
5. Basic epidemiology
 Information learn regarding incidence, prevalence and
reservoirs
 Disease transmission like contact, vehicle and vector

25. 6. Basic disease information
 Longevity/severity – Acute, chronic, sub-chronic and latent
 Transmission – Communicable, Non-communicable
 Extent of body effect – Local , systematic
 State of host when infected – Primary and secondary
7. Controlling microbial growth
 Control microbial growth through chemical methods;
i.e., their actions, types and general precaution
 Physical methods; i.e., heat, cold, filtration and
radiation
 Antibiotics – their mechanism of action, spectrum of
activity and antibiotic resistance

26. • Ancient human believes that divine wrath and supernatural
forces are responsible for the diseases and death.
• Later, different concepts are portrayed by ancient such as
influence of environment, bodily constitution and faulty diet.
• The Roman philosopher Lucratitus and the physician
Girolamo Fracastora suggested that disease was caused by
invisible living creatures.
• The earlier microscopic observation appears to have been made
between 1625 to 1630 on bees by Italian Francesco Stelluti,
using microscope supplied by Galileo.

27. • He spent his money and time in preparing lenses
• In 1671, he constructed first simple microscope
• Through, his, microscope he examined skin, hair and his on
blood
• He published reported to British royal society in 1673.
• In 1676, he sent information to Royal society
about discovery of tiny one-celled animals in
rainwater
• In 1680, society elected him as member
• Disapproves spontaneous generation in 1683

28. • He introduced the idea of pasteurization (Conventional, Flash
and Ultra high)
• He established relationship between microorganism and disease,
and concept of destroying microorganisms to stop the
transmission of communicable diseases
• Tackled problem of French beverage industry from avoiding
wine turn sour by heating the wine gently at 42 ºC would kill the
bacteria that produced lactic acid
• Postulates germ theory of diseases that infectious diseases are
due to the activities of microorganism
• Developed techniques for culturing

29. • Cultured bacteria that cause Cholera
• Developed Anthrax vaccine
• Developed Rabies vaccine from
the spinal fluid of infected rabbits
• Coined the term Microbiology
• Father of Bacteriology

30. • He examined the blood of infected sheet under the microscope
and confirmed that anthrax was caused by a bacillus
• In 1877, he used different techniques to isolate Bacillus
anthracis, he used dry fixed bacterial cultures onto glass slides,
stained the culture with dyes to observe them and photopgraphed
through microscope
• Worked on tuberculosis (TB) and awarded Nobel prize on 1905
for physiology and medicine
• He invented hot air oven and stream sterilizer towards
sterilization methods
• Introduced four basic criteria known as “Koch’s postulates”

31. • “Koch’s postulates”
1. The organism must be found in the tissues of animals with
the disease and not in disease-free animals.
2. The organism must be isolated from the diseased animal and
grown in pure culture outside the body.
3. The cultured organism must be able to be transferred to a
healthy animal, which will subsequently show signs of
infections.
4. The organism must be able to be isolated from the infected
animals.

33. • Limitations of “Koch’s postulates”
1. Infectious organism such as bacterium “Mycobacterium
leprae”, some viruses and prions cannot be grown in artificial
laboratory media.
2. Microorganism are normally part of normal flora of a host
becomes capable of causing diseases when introduced into a
different environment in the host (e.g., Staphyloccocus
aureus) or when the host’s immune system is malfunctioning.
E.g., Serratia marcescens

34. • Introduced method of vaccination for smallpox
• He called his method Vaccination,
using Latin word “vacca” meaning cow
and “vaccinia” meaning Cow pox

35. • 348-322 BC: Aristotle and other believed that living organism
could develop from non-living materials
• 1590: Zacharias Janssen- developed first compound
microscope

36. • 1660: Robert Hooke – Published “micrographia” drawing and
detailed observations of biological materials made with the best
compound microscope
• 1676: Anton van Leeuwenhoek – 1st person to observe
microorganism

37. • Spontaneous generation controversy
• 1688: Francesco Redi (1626-1678) - was an Italian
physician who refuted the idea of spontaneous generation by
showing that rotting meat carefully kept from flies will not
spontaneously produce maggots.
• 1836: Theodor Schwann (1810-1882) - helped develop the
cell theory of living organisms, namely that that all living
organisms are composed of one or more cells and that the cell
is the basic functional unit of living organisms.

38. • Joseph Lister (1827-1912) - introduced antiseptics in surgery.
By spraying carbolic acid on surgical instruments, wounds and
dressings, he reduced surgical mortality due to bacterial
infection considerably.
• He is known as father of antiseptic surgery
• Roux and Yersin discovered Dipthera toxin
• Ivanovasky found the existence of viruses
• Walter reed demonstrated that yellow fever was caused by
viruses
• Medwar and Burnet developed the methods for immune
suppression

39. • Zacharias and Hans janssen developed the first compound
microscope
• Eile Metchnikoff discovers the antibacterial activity of WBC
called phagocytes
• Paul Ehrlich discovered the treatment of Syphilis by using
Arsenic.
• Ruska develop a primitive electron microscope
• Alexander Fleming discovers penicillin