IntroductionIntroduction
Medical MicrobiologyMedical Microbiology
Hope Tan
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
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
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
IntroductionIntroduction
• ObjectsObjects• ContentsContents• ObjectiveObjective• Techniques Techniques • StatusStatus
Research objectsResearch objects
Definition of microorganism
an organism that is too small to be seen without the aid of a microscope
Characters of microorganisms
Minute volume, simple structurewide range nutriment 、 active metabolismreproduce quickly 、 large quantity 、 widespreadvariation and adaptability easily
Prokaryotic microorganisms
Eukaryotic microorganisms
Non cellular microorganisms
Classification
Eukaryotic microorganisms
• Eukaryotes – Larger – Complex structure
• Nucleus • Both DNA and RNA • Various organelles
Eukaryotic microorganisms
• Eukaryotes – Fungi
• Yeasts • Molds
– Reproduction • Budding • Production of spores
Prokaryotic microorganisms • Prokaryotes
– Small – Relatively simple structure
• Nucleoid • Both DNA and RNA • A single organelle
Prokaryotic microorganisms
• Prokaryotes – Members
• Bacteria • Mycoplasmas • Rickettsiae • Chlamydiae • Spirochetes • Actinomyces
– Reproduction • binary fission
Non cellular 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
The Importance of MicroorganismsThe Importance of Microorganisms
Circulation of materialsCirculation of materialsMedicineMedicine 、、 FoodFood 、、 IndustryIndustryMicro-ecosystemMicro-ecosystem
Microbes Benefit Humans
Microbes are used to produce Antibiotics
Penicillin
Mold Penicillium notatum
1928 Alexander Fleming
Bacteria synthesize chemicals that our body needs, but cannot synthesize
Example: E. coliB vitamins - for metabolismVitamin K - blood clotting
Microbial Antagonism
Our normal microbial flora prevents potential pathogens from gaining access to our body
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
Anthrax
Pathogenic microorganism cause many diseases
disease: tetanus、 fungus infection、gas gangrene
tetanustetanus gas gangrenegas gangrene Fungus nailFungus nail
AIDS
SARS
Ebola
DiseasesDiseases
Research contentsResearch contents
Microbiology is the biology of microorganis
ms. It is a bioscience for the study of the evolutio
n, classification , morphology, physiology,
genetics, ecology of microbes under certain defini
te conditions, the law of their life activities, and t
heir interaction with human being, animals or pla
nts as well as with natural environment.
Microbiology
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
Research objectiveResearch objective
Diagnostic assistance: Qualitation and/or quantitation for pathogens
Therapic guidance: Detection of drug resistance
Disease prevention: Development vaccines and/or new generation vaccines
Unique Research TechniquesUnique Research Techniques
The Four Classic Research TechniquesThe Four Classic Research Techniques
Microtechnique Aseptic technique Culture technique Staining technique
Microtechnique
1673-1723, Leeuwenhoek (Dutch) described live microorganisms that he observed in teeth scrapings, rain water, and peppercorn infusions.
Anton van Leeuwenhoek - 1st person to actually see living microorganisms
“wee animalcules”
( Leeuwenhoek ) 1632-1723
32
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
Magnifier
Light microscope
electron microscope
atomic force microscope
Aseptic technique
1859, Louis Pasteur discoved that the deterioration was caused by microbes and invented pastereurization.
Louis Pasteur was born on December 27, 1822 Louis Pasteur was born on December 27, 1822 in Dole, in the Region of Jura, France. His in Dole, in the Region of Jura, France. His discovery that most infectious diseases are caused discovery that most infectious diseases are caused by germs, known as the"germ theory of disease", is by germs, known as the"germ theory of disease", is one of the most important in medical history. His one of the most important in medical history. His work became the foundation for the science of work became the foundation for the science of microbiology, and a cornerstone of modern microbiology, and a cornerstone of modern medicine.medicine.
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
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 .
Koch’s postulatesKoch’s postulates1. 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.
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-
The protocol of Gram stain
Gram stain morphology Shape
coccibacilli spiral or curved
Single or multiple cellsclusters (e.g. streptococci)chains (e.g. streptococci)
Gram positive or negative
Significance of Gram Stain
• Differentiate bacteria: G + / G
• Helpful to select sensitive antibiotics.
• identify different virulent factors of bacteria.
– G + : exotoxin
– G : endotoxin.
Research StatusResearch Status
A
Diagnosis——pathogen and its antigen, nucleic acid, metabolites, antibody
Prevention——vaccines
Therapy——antibiotics
The first medical revolution
Achievements
The second medical revolution
Discovery origin for hereditary material
Tools for gene engineering research
Model for human genome research
B
Developmental direction and perspectives
•Emerging and re-emerging pathogens•Pathogenic mechanisms•Development and exploitation for anti-infection drugs• Development and improvement of vaccines
Nowadays New pathogens emerged continuously
Hepatitis viruseHIVTTVPrionsCoronavirus and SARS
Re-emerging of traditional pathogensDrug resistance became more severeMycobacterium toberculosis
Progress of Hepatitis Viruses 1947, concepts of hepatitis A and serum-tra
nsmitted hepatitis
1970, Dane particle was observed (hepatitis B virus)
1973, hepatitis A virus
1978, non-A, non-B hepatitis viruses (NANBV)
1989, hepatitis C virus (HCV), hepatitis E virus (HEV)
1990-1994, non A-E hepatitis viruses
1995, hepatitis G virus (HGV)
1997, TT virus (TTV)
Human 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
Prions Infectious pro
teinsKuruCJDMad cow dise
aseScrapie
Kuru
vCJD
BSE
Developmental direction and perspective
•Emerging and re-emerging pathogens•Pathogenic mechanisms•Development and exploitation for anti-infection drugs• Development and improvement of vaccine
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
• The definition of microorganisms • The classification of microorganisms • The differences among viruses, bacteria,
and fungi
Summary
• The four main research techniques