Introduction to medical microbiology . general introduction

1. IntroductionIntroduction
Medical MicrobiologyMedical Microbiology
Hope Tan

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

3. 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 covered
with microbes

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

5. IntroductionIntroduction
• ObjectsObjects
• ContentsContents
• ObjectiveObjective
• TechniquesTechniques
• StatusStatus

6. Research objectsResearch objects

7. Definition of microorganism
an organism that is too small to be seen
without the aid of a microscope

8. Characters of microorganisms
Minute volume, simple structure
wide range nutriment 、 active metabolism
reproduce quickly 、 large quantity 、 widespread
variation and adaptability easily

9. Prokaryotic
microorganisms
Eukaryotic
microorganisms
Non­cellular
microorganisms
Classification

10. Eukaryotic microorganisms
• Eukaryotes
– Larger
– Complex structure
• Nucleus
• Both DNA and RNA
• Various organelles

11. Eukaryotic microorganisms
• Eukaryotes
– Fungi
• Yeasts
• Molds
– Reproduction
• Budding
• Production of spores

12. Prokaryotic microorganisms
• Prokaryotes
– Small
– Relatively simple structure
• Nucleoid
• Both DNA and RNA
• A single organelle

13. Prokaryotic microorganisms
• Prokaryotes
– Members
• Bacteria
• Mycoplasmas
• Rickettsiae
• Chlamydiae
• Spirochetes
• Actinomyces
– Reproduction
• binary fission

14. Non­cellular microorganisms
• Smallest
• Simple structure
– No cell structure
• Nucleic acid
• Capsid
• Envelope
– Either DNA or RNA
• Obligate intracellular parasites
– Viruses are replicated only when
they are in a living host cell
• Members
– Viruses
• Reproduction
– Replication

16. The Importance of MicroorganismsThe Importance of Microorganisms
Circulation of materialsCirculation of materials
MedicineMedicine 、、 FoodFood 、、 IndustryIndustry
Micro-ecosystemMicro-ecosystem
Microbes Benefit Humans

17. Microbes are used to produce AntibioticsMicrobes are used to produce Antibiotics
 Penicillin
 Mold
Penicillium notatum
 1928 Alexander Fleming

18. Bacteria synthesize chemicals that our body needs,
but cannot synthesize
Bacteria synthesize chemicals that our body needs,
but cannot synthesize
 Example: E. coli
B vitamins - for metabolism
Vitamin K - blood clotting
 Example: E. coli
B vitamins - for metabolism
Vitamin K - blood clotting

19. Microbial AntagonismMicrobial Antagonism
Our normal microbial flora prevents
potential pathogens from gaining access to
our body
Our normal microbial flora prevents
potential pathogens from gaining access to
our body

20. Harmful activities:
A portion of microbes can cause
diseases and/or are poisonous to animal,
plant or human being, and these which
cause diseases to human are really that
concern us in the study of medical
microbiology.
Pathogenic microorganism

21. Anthrax
Pathogenic microorganism
cause many diseases
Pathogenic microorganism
cause many diseases

22. disease ： tetanus 、 fungus infection 、
gas gangrene
tetanustetanus gas gangrenegas gangreneFungus nailFungus nail

23. AIDS
SARS
Ebola
DiseasesDiseases

24. Research contentsResearch contents

25. Microbiology is the biology of
microorganisms. It is a bioscience for the
study of the evolution, classification ,
morphology, physiology, genetics, ecology of
microbes under certain definite conditions, the
law of their life activities, and their interaction
with human being, animals or plants as well as
with natural environment.
Microbiology

26. The science that study the biological
characters, infectious and immune
mechanisms, specific diagnosis, prevention
and cure measurement of pathogenic
microorganism is called medical
microbiology.
Medical Microbiology

27. Research objectiveResearch objective

28. Diagnostic assistance: Qualitation and/or
quantitation for pathogens
Therapic guidance: Detection of drug
resistance
Disease prevention: Development vaccines
and/or new generation vaccines

29. Unique Research TechniquesUnique Research Techniques

30. The Four Classic Research TechniquesThe Four Classic Research Techniques
Microtechnique
Aseptic technique
Culture technique
Staining technique

31. Microtechnique
1673-1723,
Leeuwenhoek (Dutch)
described live
microorganisms that he
observed in teeth
scrapings, rain water,
and peppercorn
infusions.

32. Anton van Leeuwenhoek
- 1st person to actually see living microorganisms
“wee animalcules”
（ Leeuwenhoek ） 1632-1723
32

33. He assembled over 247 microscopes, some of
which magnified objects 270 times. In the course of
his examination of innumerable microorganisms
and tissue samples, he gave the first complete
descriptions of the bacteria, the protozoans (which
he called animalcules), spermatozoa, and striped
muscle. He also observed the red blood cells in his
detailed study of capillary circulation. He was
elected to the Royal Society of England in
recognition of his work.
Anton van Leeuwenhoek

34. Magnifier
Light microscope
electron microscope
atomic force microscope

35. Aseptic technique
1859, Louis Pasteur discoved that the
deterioration was caused by microbes and invented
pastereurization.

36. Louis Pasteur was born on December 27, 1822Louis Pasteur was born on December 27, 1822
in Dole, in the Region of Jura, France. Hisin Dole, in the Region of Jura, France. His
discovery that most infectious diseases are causeddiscovery that most infectious diseases are caused
by germs, known as the"germ theory of disease", isby germs, known as the"germ theory of disease", is
one of the most important in medical history. Hisone of the most important in medical history. His
work became the foundation for the science ofwork became the foundation for the science of
microbiology, and a cornerstone of modernmicrobiology, and a cornerstone of modern
medicine.medicine.

37. In 1865, Joseph Lister, a British surgeon, established
antiseptic surgery by introducing aseptic technique to
this field. For many years he had explored the
inflammation of wounds at the Glasgow infirmary. These
observations had led him to considered that infection was
not due to bad air alone, and that 'wound sepsis' was a
form of decomposition

38. Cuture technique
In 1881, Robert KochIn 1881, Robert Koch, a German
bacteriologist, isolated bacteria using
solid medium and then he associated
many diseases with specific microbes.
In 1884, he devised a hypothesis
known as Koch’s Postulates designed
to establish a causal relationship
between a causative microbe and a
disease .

39. Koch’s postulatesKoch’s postulates
1. The same organisms must be found in all cases of a given
disease.
2. The organism must be isolated and grown in pure culture.
3. The isolated organism must reproduce the same disease
when inoculated into a healthy susceptible animal.
4. The original organism must be isolated again from the
experimentally infected animal.

40. Staining technique
Amidobenzene was applied to stain bacteria
in suspension by German pathologist named
Weigert, then Koch improved it and stained the
bacteria on a slide. In 1884, Christian Gram, a
famous Denmark pathologist invented a stain
technique which is known as Gram Stain now to
stain bacteria on a slide, by this technique, all
bacteria can be classified as G+
and C-

41. The protocol of Gram stain

42. Gram stain morphology
 Shape
cocci
bacilli
spiral or curved
 Single or multiple cells
clusters (e.g. streptococci)
chains (e.g. streptococci)
 Gram positive or negative

46. Significance of Gram Stain
• Differentiate bacteria: G +
/ G ­
• Helpful to select sensitive antibiotics.
• identify different virulent factors of bacteria.
– G +
: exotoxin
– G ­
: endotoxin.

47. Research StatusResearch Status

48. A
Diagnosis——pathogen and its antigen, nucleic
acid, metabolites, antibody
Prevention——vaccines
Therapy——antibiotics
The first medical
revolution
Achievements
The second medical
revolution

49. Discovery origin for hereditary material
Tools for gene engineering research
Model for human genome research
B

50. Developmental direction and
perspectives
•Emerging and re­emerging pathogens
•Pathogenic mechanisms
•Development and exploitation for anti­infection
drugs
• Development and improvement of vaccines

51. NowadaysNowadays
 New pathogens emerged continuously
Hepatitis viruse
HIV
TTV
Prions
Coronavirus and SARS
 Re­emerging of traditional pathogens
Drug resistance became more severe
Mycobacterium toberculosis
 New pathogens emerged continuously
Hepatitis viruse
HIV
TTV
Prions
Coronavirus and SARS
 Re­emerging of traditional pathogens
Drug resistance became more severe
Mycobacterium toberculosis

52. Progress of Hepatitis VirusesProgress of Hepatitis Viruses
 1947, concepts of hepatitis A and serum­
transmitted hepatitis
 1970, Dane particle was observed (hepatitis
B virus)
 1973, hepatitis A virus
 1978, non­A, non­B hepatitis viruses
(NANBV)
 1989, hepatitis C virus (HCV), hepatitis E
virus (HEV)
 1990­1994, non A­E hepatitis viruses
 1995, hepatitis G virus (HGV)
 1997, TT virus (TTV)
 1947, concepts of hepatitis A and serum­
transmitted hepatitis
 1970, Dane particle was observed (hepatitis
B virus)
 1973, hepatitis A virus
 1978, non­A, non­B hepatitis viruses
(NANBV)
 1989, hepatitis C virus (HCV), hepatitis E
virus (HEV)
 1990­1994, non A­E hepatitis viruses
 1995, hepatitis G virus (HGV)
 1997, TT virus (TTV)

53. Human Immunodeficiency Virus & AIDSHuman Immunodeficiency Virus & AIDS
 1981, the first cases report
about AIDS
 1983, HIV was isolated
 1990s, HAART (cocktail
therapy) was employed
 So far, no effective vaccine
available
 1981, the first cases report
about AIDS
 1983, HIV was isolated
 1990s, HAART (cocktail
therapy) was employed
 So far, no effective vaccine
available

54. PrionsPrions
 Infectious
proteins
Kuru
CJD
Mad cow
disease
Scrapie
 Infectious
proteins
Kuru
CJD
Mad cow
disease
Scrapie
Kuru
vCJD
BSE

55. Developmental direction and perspective
•Emerging and re­emerging pathogens
•Pathogenic mechanisms
•Development and exploitation for anti­infection
drugs
• Development and improvement of vaccine

56. How to Study Medical Microbiology?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

57. • The definition of microorganisms
• The classification of microorganisms
• The differences among viruses, bacteria,
and fungi
Summary
• The four main research techniques