INTRODUCTION TO BASIC MICROBIOLOGY

1. INTRODUCTION
TO
MEDICAL MICROBIOLOGY
PRESENTED BY :MISS TASMIA ZEB
MICROBIOLOGY
1

2. 2
What is Microbiology?
Microbes, or microorganisms are minute living
things that are usually unable to be viewed with the
naked eye.
What are some examples of microbes?
Bacteria, fungi, protozoa, algae, viruses are
examples!
Some are pathogenic
Many are beneficial

3. Microbiology defined as the study of
organisms too small to be seen with the
naked eye. These organisms include viruses,
bacteria, algae, fungi, and protozoa.
Microbiologists are concerned with
characteristics and functions such as
morphology,cytology,physiology,ecology,taxon-
omy,genetics, and molecular biology.
Defining Microbiology

4. What is Microbiology
• Study of different
Microorganisms
• Can be
Bacteria
Viruses
Parasites
Fungus
4

5. What are Microorganisms
• Microbes are
products of
evolution,
Consequence of
Natural selection
operating upon
vast array of
genetically diverse
organisms
5

6. History of Microbiology
1673-1723, Antoni
van Leeuwenhoek
(Dutch) described
live
microorganisms
that he observed in
teeth scrapings,
rain water, and
peppercorn
infusions. 6

7. Anton van Leeuwenhoek 1674
- 1st person to actually see living microorganisms
“wee animalcules”
荷兰人吕文虎克
（Leeuwenhoek）1632-1723
7

8. 8
History of Microbiology
The Germ Theory of Disease
1835: Agostino Bassi showed a silkworm
disease was caused by a fungus.
1865: Pasteur believed that another silkworm
disease was caused by a protozoan.
1840s: Ignaz Semmelweis advocated
handwashing to prevent transmission of
puerperal fever from one OB patient to
another.

9. 9
The Germ Theory of Disease
• 1860s: Joseph Lister used a
chemical disinfectant to
prevent surgical wound
infections after looking at
Pasteur’s work showing
microbes are in the air, can
spoil food, and cause animal
diseases.

10. 10
History of microbiology
Anton van Leeuwenhoek (1632–1723): was the first
microbiologist and the first person to observe bacteria
using a single-lens microscope of his own design.
Louis Pasteur (1822–1895): Pasteur developed a
process (today known as pasteurization) to kill microbes.
pasteurization is accomplished by heating liquids to 63
to 65 C for 30 minutes orto 73 to 75 C for 15seconds.
Robert Koch (1843–1910): was a pioneer in medical
microbiology and worked in cholera, anthrax and
tuberculosis. He was awarded a Nobel prize in 1905
(Koch's postulates) he set out criteria to test.
 Alexander Fleming (1929): Discovered penicillin.

11. Joseph Lister
• 1860s: Joseph Lister
used a chemical
disinfectant to
prevent surgical
wound infections
after looking at
Pasteur’s work
showing microbes are
in the air, can spoil
food, and cause
animal diseases.
11

12. MEDICAL MICROBIOLOGY INCLUDES
• General
Microbiology
• Bacteriology
• Mycology
• Virology
• Immunology
• Parasitology
12

13. Microbes in Our Lives
• Microorganisms
are organisms that
are too small to be
seen with the
unaided eye.
• “Germ” refers to a
rapidly growing
cell.
13

14. ADVANTAGES OF MICROBES
•KEEP US HEALTHY
•MAKE AIR BREATHEABLE
•PROVIDE SOURCES OF NEW MEDICINES
•HELP US IN DIGESTION OF FOOD
•KEEP OUR ENVIRONMENT CLEAN
•SUPPORT AND PROTECT CROPS

15. Microbes make the Universe
• There are > 5 x 1030
types Microbes in
the world
• Humans have
intimate relation
with Microbes > 90%
of the cells in our
Body are Microbes
15

16. Classification of Microorganisms
• Three domains
–Bacteria
–Archaea
–Eukarya
• Protists
• Fungi
• Plants
• Animals
16

17. Naming and Classifying
Microorganisms
• Carolus Linnaeus (1735)
established the systemof
scientific nomenclature.
• Each organism has two
names: the genus and
specific epithet.
• Are italicized or
underlined. The genus is
capitalized and the
specific epithet is lower
case.
17

18. Edward Jenner Vaccinating a
Child
18

19. Louis Pasteur
1922 - 95
• Contributed best in
Microbiology
• Sterilization
• Hot Air oven
• Autoclave
• Anthrax vaccine
• Rabies vaccine
• Built the Pasteur
Institute
19

20. Louis Pasteur
• Pasteur coined the
word Vaccine
• Vacca – Cow cow
pox virus are given for
the prevention of
Small Pox
• Louis Pasteur
considered the father
of Modern
Microbiology
20

21. Robert Koch
1843 - 1910
• A German scientist
• Formulated the
Bacteriological
techniques
• Staining Methods
• Discovered the
Mycobacterium and
Vibrio cholera
21

22. Biological Principles illustrated by
Microbiology
Microbiology
Biochemistry
Molecular
Biology
Genetics
24

23. Microorganisms
Non-cellular organism
Prokaryotes
Eukaryotes
Others Prions Viroid
Fungi
Bacterium
Virus
23

24. Organisms included in the study
of Microbiology
1. Bacteria
2. Protozoans
3. Algae
4. Parasites
5. Yeasts and Molds
Fungi
6. Viruses
Bacteriology
Protozoology
Phycology
Parasitology
Mycology
Virology
24

25. 25
How to Study Medical Microbiology?
Fundamentals of Microbiology
Bacteriology
Virology
Mycology
•Biological Properties
•Morphology, identification,
•Antigenic structure
•Pathogenesis and Pathology
•Clinical findings
•Diagnostic Laboratory Tests
•Immunity
•Treatment & Prevention
•Epidemiology & Control

26. 26
Basic Classification of Microorganism
• Eukaryotes
Large in size
Mitochondria Present
Membrane bound Nucleus
Eg Algae
Protozoa
Fungi
Slime Moulds
Contains all enzymes for
production of metabolic
energy
Prokaryotes
Small in Size
DNA not separated from
cytoplasm
Mitochondria absent
Eg Bacteria
Contains all enzymes like
Eukaryotes

27. Prokaryotic cells Eukaryote cells
Small cell (< 5µm) Larger cells (> 10 µm)
Always unicellular Often multicellular
No nucleus or any membrane bound organelles Always have nucleus and membranes bound
organelles.
DNA circular, without proteins DNA is linear and associated with proteinsto
form chromatin.
Ribosomes are small 70S Ribosomes are large 80S
No cytoskeleton Always have cytoskeleton
Motility by rigid rotating flagellum made from
flagellin
Motility by flexible waving cilia or flagella
made from tubulins.
Cell division is by binary fission Cell division is by meiosis and mitosis.
Reproduction is always asexual Reproduction is sexual and asexual.
Summary of differences between
prokaryote and eukaryote cells

28. Prokaryotic Cell Structure
Prokaryotic cells are about 10 times smaller
than eukaryotic cells. A typical Escherichia coli
cell is about 1 μm wide and 2 to 3 μm long.
Structurally, prokaryotes are very simple cells
when compared with eukaryotic cells, and yet
they are able to perform the necessary
processes of life. Reproduction of prokaryotic
cells is by binary fission, the simple division of
one cell into two cells, after DNA replication and
the formation of a separating membrane and cell
wall.

29. Bacteria
• Prokaryotes
• Peptidoglycan cell
walls
• Binary fission
• For energy, use
organic chemicals,
inorganic chemicals,
or photosynthesis
32

30. Bacterial Cell Wall
The structure of bacterial cell walls is quite different from
the relatively simple structure of eukaryotic cell walls,
although they serve the same functions, providing rigidity,
strength, and protection. The main constituent of most
bacterial cell walls is a complex macromolecular polymer
known as peptidoglycan (murein), consisting of many
polysaccharide chains linked together by small peptide
(protein) chains. Peptidoglycan is only found in bacteria. The
thickness of the cell wall and its exact composition vary with
the species of bacteria. The cell walls of “Gram-positive
bacteria” have a thick layer of peptidoglycan combined with
teichoic acid and lipoteichoic acid molecules. The cell walls of
“Gram-negative bacteria” have a much thinner layer of
peptidoglycan, but this layer is covered with a complex layer
of lipid macromolecules, usually referred to as bacteria
capsule.

31. Figure 1-9: Gram
Stain

32. Figure 3-1. Various forms of bacteria, including single cocci, diplococci, tetrads,
octads, streptococci, staphylococci, single bacilli, diplobacilli, streptobacilli,
branching bacilli, loosely coiled spirochetes, and tightly coiled spirochetes.

33. Morphologic arrangements of
bacteria.

34. Capsule stain. The capsule stain is an example of a negative staining technique. The
bacterial cells and the background stain, but the capsules do not. The capsules are
seen as unstained “halos” around the bacterial cells.

35. . Flagellar arrangement. The four basic types of flagellar arrangement on bacteria:
peritrichous, flagella all over the surface; lophotrichous, a tuft of flagella at one end;
amphitrichous, one or more flagella at each end; monotrichous, one flagellum.

36. Binary fission. Note that DNA replication must occur before the actual
splitting (fission) of the parentcell.

37. Pathogenic Prokaryotes
37
Mycoplasma
Bacteria
Spirochetes
Rickettsia
Chlamydiae
Actinomyces

38. Viruses
Viruses lack many of the attributes of cells, including the ability to
replicate. Only when it infects a cell does a virus acquire the key
attribute of a living system: reproduction
A viral particle consists of a nucleic acid molecule, either DNA or RNA,
enclosed in a protein coat, or capsid
Viruses are known to infect all cells, including microbial cells. Host-virus
interactions tend to be highly specific
38

39. Discovery of Virus
• Iwanovski
– a Russian chemist, 1892
– Tobacco Mosaic Disease
• Beijerinck confirmed
• Walter Reed, USA
– Yellow fever virus
– Ist human virus
Tobacco mosaic disease,
caused by the tobacco
mosaic virus
39

40. Viruses
• A virus is not a cell!
• Viruses are replicated
only when they are in a
living host cell
• Consist of DNA or RNA
core
• Core is surrounded by a
protein coat
• Coat may be enclosed in
a lipid envelope
40

41. What are Viruses
• Viruses Dependent on
Host cells for necessary
functions and
Multiplication
• Intracellular
parasites
• Contain either
DNA or RNA
never both.
41

42. Prion
42
A kind of infectious protein that can resist the digestion of proteinase
The cellular form of the prion protein (PrPc) is encoded by the host’s
chromosomal DNA
An abnormal isoform of this protein (PrPres) is the only known
component of the prion and is associated with transmissibility.
Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-
Sträussler-Scheinker disease, fatal familial insomnia
, and Bovine spongiform encephalopathy (BSE)

43. Viroid
43
Small, single-stranded, covalently closed circular RNA molecules
existing as highly base-paired
rod-like structures; they do not possess capsids
extracellular form of the viroid is naked RNA—there is no capsid of any
kind
is therefore totally dependent on host functions for its replication
They range in size from 246 to 375 nucleotides in length. The
The RNA molecule contains no protein-encoding genes, and the viroid
The RNAs of viroids have been shown to contain
inverted repeated base sequences at their 3' and 5' ends, a
characteristic of transposable elements and retroviruses. Thus, it is
likely that they have evolved
from transposable elements or retroviruses by the deletion of internal
sequences

44. 44
Koch’s Postulates
1 The bacterium should be constantly associated with
lesions of Disease
2 It should be possible to isolate the bacterium in pure
culture from the lesions
3 Inoculation of such pure culture into laboratory animal
should reproduce the lesions of the disease
4 It is possible to reisolate the bacterium in pure culture
from the lesions produced in the experimental animal
Additional criterion specific antibodies in the
serum of patients suffering with disease

45. Koch’s postulates
45

46. 1928: Alexander
Fleming discovered
the first antibiotic.
He observed that
Penicillium fungus
made an antibiotic,
penicillin, that killed
S. aureus.
1940s: Penicillin was
tested clinically and
mass produced.
Scientific era of Antibiotics
46

47. Discovery of Antibiotics
• Alexander Fleming (1881-1955)
Sir Alexander Fleming Ernst Boris Chain Sir Howard Walter Florey
47

48. Microbes are used to produce
Antibiotics
• Penicillin
• Mold
– Pencillium notatum
• 1928 Alexander Fleming
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49. 49
Modern Developments
• Bacteriology is the study of bacteria.
• Mycology is the study of fungi.
• Parasitology is the study of protozoa and
parasitic worms.
• Recent advances in genomics, the study of
an organism’s genes, have provided new
tools for classifying microorganisms.

50. 50
Microbes and Human Disease
• Normal micro biota prevent growth of
pathogens.
• Normal micro biota produce growth factors
such as folic acid and vitamin K.
• Resistance is the ability of the body to
ward off disease.
• Resistance factors include skin, stomach
acid, and antimicrobial chemicals.

51. Bacteria - what comes to mind?
• Diseases
• Infections
• Epidemics
• Food Spoilage
• Only 1% of all known bacteria cause human
diseases
• About 4% of all known bacteria cause plant
diseases
• 95% of known bacteria are non-pathogens
51

52. • Staphylococcus aureus
• Staphylococcus
epidermidis
• Streptococcus
pneumonia
• Vibrio cholera
• Rhodospirillium rubrum
• Bacillus subtilis
• Micrococcus luteus
• Escherichia coli
• Bacillus anthrasis
• Salmonella enteridis
• Streptococcus pyogenes
• Steptococcus lactis
• Streptococcus faecalis
• Erlichia canis
• Campylobacter jujuni
• Helicobacter pylori
• Enterobacter aerogenes
52

53. Microbes Benefit Humans
1.Bacteria are primary decomposers - recycle
nutrients back into the environment (sewage
treatment plants)
2. Microbes produce various food products
– cheese, pickles, sauerkraut, green olives
– yogurt, soy sauce, vinegar, bread
– Beer, Wine, Alcohol
53

54. Microbes are also capable of
causing many diseases
Pneumonia Whooping Cough
Botulism Typhoid Fever Measles
Cholera Scarlet Fever Mumps
Syphilis Gonorrhea Herpes 1
Chlamydia Tuberculosis Herpes 2
Meningitis Tetanus RMSV
Strep Throat Lyme Disease AIDS
Black PlagueDiarrhea Gangrene 58

55. Parasitology
• Parasitology is the study of parasites .and their
interactions with their hosts. The science of parasitology
has a long history and has its roots in zoology, with its
emphasis on the identification and classification of
parasites and of life cycles,
62

56. Taxonomic classification of parasitic
organisms
• Parasites are classified into 2 sub- kingdoms:
protozoa (unicellular) and metazoa
(multicellular)
• Protozoan (unicellular) parasites are classified
according to morphology and means of locomotion.
There are 45,000 protozoa species. Most species that
cause human disease belong to the phylum's
sarcomastigophora and apicomplexa
• Metazoa (multicellular) include the worms (helminths)
and arthropoda (posses an external skeleton) e.g.
ticks, lice
• Note that the genus starts with a capital

57. What Are Fungi
• Considerable variation
in size.
• Internal Molecular
system
• Well defined cell wall
composed of
polysaccharides
• Gaining importance in
Immunosupressed
patients and increased
use of Antibiotics
57

58. Zoonotic Diseases
58

59. How Humans Respond to Infections
Study of Immunology
• In spite of Infection
we survive with our
ability to protect
with a system
inherent in our Body
• Called the Immune
response comprises
the Medical
Immunology
59

60. Why we should
Medical Microbiology
• We study the
Microbes which
infects and causes
Diseases
• We study their
Diagnosis
Prevention
Treatment
60

61. Must learn
• Natural History of the Disease
• Etiology
• Pathogenesis
• Laboratory Diagnosis
• Treatment and Control and
Prevention 72

62. We must be familiar with Knowledge
On ….
• Names of the Microbes
• Names of the diseases
• Mode of transmission
• Pathogenic Microbes
• Commensal Organisms
• Identify wether Bacteria, Virus, Parasite or
Fungi
• Treating and Preventing
62

63. 63
• Treatment with chemicals is chemotherapy.
• Chemotherapeutic agents used to treat infectious
disease can be synthetic drugs or antibiotics.
• Antibiotics are chemicals produced by bacteria and
fungi that inhibit or kill other microbes.
• Quinine from tree bark was long used to treat malaria.
• 1910: Paul Ehrlich developed a synthetic arsenic drug,
salvarsan, to treat syphilis.
• 1930s: Sulfonamides were synthesized.
The Birth of Modern Chemotherapy

64. Commonly Used Antibiotics
• Penicillin
• Cephalosporins,
• Tetracycline's
• Quinolones
• Vancomycin
• Chloramphenicol
• Drugs for Tuberculosis eg Streptomycin
Vaccines Produce Immunity and Prevents several
Infections 64

65. Commonly used Vaccines
• Small pox eradicated
• BCG,
• MMR
• Polio oral Vaccine
• Triple Antigen
• Hepatitis B Vaccine
What Skills You should Develop
65
Able to identify the Infective Conditions Timely Diagnosis
Choosing appropriatetests Selection of
Antibiotics
Implement measures to preventdiseases in patients and Society

66. Protect Yourself from
Infections
• Certain infections
can infect you
• Eg HIV, Hepatitis B
infections,Tubercul
osis,Many
respiratory
infections
66

67. Working In the Hospital
• Hospitals are not safe
• Follow Universal
precaution protect
yourself as our patients
can be source of
Infection if you don't
handle the matters with
scientific knowledge.
67

68. 68
* The first Nobel Prize in Physiology or Medicine.
Major Selected Nobel Prizes in Physiology or
Medicine
1901* von Behring Diphtheria antitoxin
1902 Ross Malaria transmission
1905 Koch TB bacterium
1908 Metchnikoff Phagocytes
1945 Fleming, Chain, Florey Penicillin
1952 Waksman Streptomycin
1969 Delbrück, Hershey, Luria Viral replication
1987 Tonegawa Antibody genetics
1997 Prusiner Prions

69. THANK YOU