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Medical Microbiology
An Introduction
Medical Microbiology:
An Introduction
Department of Microbiology
Harbin Medical University
Department of Microbiology, Harbin Medical University
Syllabus
Obligatory
classification of microbes.
Comprehensive
relationship between microbes and
human
development history of microbiology.
Department of Microbiology, Harbin Medical University
Outline
An overview of Medical Microbiology
Classification of microorganisms
Brief history
Challenges we meet now
How to study?
Assessment
Department of Microbiology, Harbin Medical University
Five Characteristics of Life
1. Cells
2. Maintain structure by taking up chemicals
and energy from the environment
3. Respond to stimuli in the external
environment
4. Reproduce and pass on their organization
to their offspring
5. Evolve and adapt to the environment
Department of Microbiology, Harbin Medical University
Prokaryotic vs. Eukaryotic
Prokaryotic Cells Without Nuclei And
Membrane-Bound Organelles
Eukaryotic Cells With Nuclei And
Membrane-Bound Organelles
Department of Microbiology, Harbin Medical University
5 Kingdoms of Living Organisms
www.oum.ox.ac.uk
Department of Microbiology, Harbin Medical University
5 Kingdoms of Living Organisms
1. Animalia [1,000,000 species]
2. Plantae [250,000 species]
3. Fungi [100,000 species]
4. Protista [250,000 species]
5. Monera [10,000 species] - Bacteria and
Cyanobacteria
Eukaryotic vs. Prokaryotic
Department of Microbiology, Harbin Medical University
Classification System
Three Domains 1978 Carl Woese 1. Bacteria
Unicellular prokaryotes with cell wall containing peptidoglycan
2. Archaea Unicellular prokaryotes with no peptidoglycan in cell
wall
3. Eukarya Protista
Fungi
Plantae
Animalia
Department of Microbiology, Harbin Medical University
Department of Microbiology, Harbin Medical University
Taxonomic Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Primate
Hominidae
Homo
Sapien
Human Being
Department of Microbiology, Harbin Medical University
Binomial System of Taxonomic
Classification
Use only the Genus and species Homo sapien Felis domestica Escherichia coli Staphylococcus aureus
Genus and species are either underlined or italicized Genus is always Capitilized species is never capitilized
Department of Microbiology, Harbin Medical University
What is Microbiology?
Micro - too small to be seen with the naked eye
Bio - life
ology - study of
Microbiology – Science about small living things
The morphology and structures
Physiology
Pathogenesis and Immunology (medical microbiology)
Treatment and prevention (medical microbiology)
Department of Microbiology, Harbin Medical University
Biological Principles illustrated by
Microbiology
Microbiology
Biochemistry Molecular
Biology Genetics
Department of Microbiology, Harbin Medical University
Evolution
Microorganisms are the products of
evolution
the biologic consequence of natural selection
operating upon a vast array of genetically
diverse organisms
Mutualism Symbiosis
Parasitism
Ecology
An association between
organisms of two different
species in which each member
benefits
A relationship of mutual
benefit or dependence
The characteristic
behavior or mode of
existence of a parasite or
parasitic population The science of the
relationships between
organisms and their
environments
Department of Microbiology, Harbin Medical University
Organisms included in the study
of Microbiology
1. Bacteria
2. Protozoans
3. Algae
4. Parasites
5. Fungi
Yeasts and Molds
6. Viruses
Bacteriology
Protozoology
Phycology
Parasitology
Mycology
Virology
Microorganisms - Microbes - Germs
Department of Microbiology, Harbin Medical University
Organisms Related To Medical
Microbiology
Acellular microbes
Viruses
Prokaryotic microbes
Bacteria
Eubacteria Chlamydia
Spirochetes Rickettsiae
Mycoplasma Actinomycetes
Eukaryotic microbes
Fungi
Department of Microbiology, Harbin Medical University
Microorganisms
Non-cellular organism
Prokaryotes
Eukaryotes
Others Prions Viroid
Fungi
Bacterium
Virus
Department of Microbiology, Harbin Medical University
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
True nucleus
PROKARYOTES
BACTERIA ARCHAEA
EUKARYOTES Prokaryotes
Cyanobacteria Eubacteria
Intron
Department of Microbiology, Harbin Medical University
Pathogenic Prokaryotes
Mycoplasma
Bacteria
Spirochetes
Rickettsia
Chlamydiae
Actinomyces
Department of Microbiology, Harbin Medical University
Eukaryotes
Algae
Fungi
Protozoa
all organisms that produce O2 as a
product of photosynthesis. One major
subgroup of these organisms—the
bluegreen bacteria, or cyanobacteria—
are prokaryotic and no longer are
termed algae
Protozoa are unicellular nonphoto-
synthetic protists. Belongs to
Parasitology
Mold Yeast
Department of Microbiology, Harbin Medical University
Prion
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)
Department of Microbiology, Harbin Medical University
Viroid
Small, single-stranded, covalently closed circular RNA
molecules existing as highly base-paired
rod-like structures; they do not possess capsids
They range in size from 246 to 375 nucleotides in length. The
extracellular form of the viroid is naked RNA—there is no
capsid of any kind
Department of Microbiology, Harbin Medical University
Viroid
The RNA molecule contains no protein-encoding genes, and the
viroid is therefore totally dependent on host functions for its
replication
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
Department of Microbiology, Harbin Medical University
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
Department of Microbiology, Harbin Medical University
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
Department of Microbiology, Harbin Medical University
Microbes are used to produce
Antibiotics
Penicillin
Mold
Penicillium notatum
1928 Alexander Fleming
www.studyblue.com
Department of Microbiology, Harbin Medical University
Bacteria synthesize chemicals that our body
needs, but cannot synthesize
Example: E. coli
B vitamins - for metabolism
Vitamin K - blood clotting
Escherichia coli
Dr. Escherich
Colon (intestine)
Department of Microbiology, Harbin Medical University
Microbial Antagonism
Our normal microbial flora prevents
potential pathogens from gaining access to
our body
Department of Microbiology, Harbin Medical University
Recombinant DNA Technology Gene Therapy
Genetic Engineering
Bacteria can be manipulated to produce enzymes and proteins they normally would not produce
Insulin
Human Growth Hormone
Interferon
Department of Microbiology, Harbin Medical University
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 Plague Diarrhea Gangrene
Department of Microbiology, Harbin Medical University
Brief History of Microbiology
Department of Microbiology, Harbin Medical University
History of the Study of
Microorganisms
1665 Robert Hooke
“little boxes” - “cells”
Cell Theory - all living things are
made up of cells
Department of Microbiology, Harbin Medical University
Anton van Leeuwenhoek 1674
- 1st person to actually see living microorganisms
“wee animalcules”
荷兰人吕文虎克
(Leeuwenhoek)1632-1723
Department of Microbiology, Harbin Medical University
Spontaneous Generation
Theory that life just “spontaneously”
developed from non-living matter
Example:
toads, snakes and mice - moist soil
flies and maggots - manure and decaying flesh
Department of Microbiology, Harbin Medical University
Germ Theory of Disease
Hard for people to believe that diseases
were caused by tiny invisible “wee
animalcules”
Diseases, they thought, were caused by:
demons
witchcraft
bad luck
the wrath of God
curses
evil spirits
Department of Microbiology, Harbin Medical University
Experiments to disprove
Spontaneous Generation
Francesco Redi 1668
Rudolph Virchow 1858
Theory of Biogenesis
Cells can only arise from preexisting cells
Louis Pasteur 1861
Department of Microbiology, Harbin Medical University
Pasteur designed special “swan-necked
flasks” with a boiled meat infusion
Shape of flask allowed air in (vital force) but trapped
dust particles which may contain microbes
Department of Microbiology, Harbin Medical University
Robert Koch 1st to prove that bacteria actually caused diseases
1876
Microbial Etiology of Infectious Disease etiology - the cause of a disease
Established “scientific rules” to show a cause and effect relationship between a microbe and a disease Koch’s Postulates
Department of Microbiology, Harbin Medical University
Koch’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 again be isolated from
the experimentally infected animal.
Department of Microbiology, Harbin Medical University
Exceptions to Koch’s Postulates
1. Some organisms have never been
grown in pure culture on artificial media Treponema pallidum - Syphilis
Department of Microbiology, Harbin Medical University
Mycobacterium leprae Leprosy
Never been grown in pure culture on artificial media
Abdominal cavity of the Seven Banded Armadillo
Exceptions to Koch’s Postulates
Department of Microbiology, Harbin Medical University
Exceptions to Koch’s Postulates
In exclusively human diseases, it is not
morally acceptable to inoculate a deadly
pathogen into a “human guinea pig”
HIV
Department of Microbiology, Harbin Medical University
Koch Postulates related 3
important diseases of his day
1. Cholera (fecal-oral disease)
Vibrio cholerae
2. Tuberculosis (pulmonary infection)
Mycobacterium tuberculosis
3. (sheep and cattle)
Bacillus anthracis
Department of Microbiology, Harbin Medical University
Discovery of Virus
Iwanovski
a Russian chemist, 1892
Tobacco Mosaic Disease
Beijerinck confirmed 1898
Walter Reed, USA 1901
Yellow fever virus
1st human virus
Tobacco mosaic disease, caused by the tobacco mosaic virus
Department of Microbiology, Harbin Medical University
Joseph Lister
Phenol to treat surgical wounds
-1st attempt to control infections
caused by microoganisms
Department of Microbiology, Harbin Medical University
Paul Erlich
1st synthetic drug used to treat infections
Salvarsan - arsenic based chemical to
treat Syphilis
“salvation” from Syphilis
Department of Microbiology, Harbin Medical University
Dicovery of Antibiotics
Alexander Fleming (1881-1955)
Sir Alexander Fleming Ernst Boris Chain Sir Howard Walter Florey
Department of Microbiology, Harbin Medical University
Vaccine and Vaccination
16 century Human pox fluid inoculation for
smallpox prevention in China
Edward Jenner, 1749-1823
Cow pox fluid inoculation for
prevention of smallpox
Smallpox was officially
declared eliminated in 1980
worldwide
Golden Age of Microbiology
1857 - 1914
Department of Microbiology, Harbin Medical University
Nowadays
New pathogens emerged continuously
Hepatitis viruses
HIV
Helicobacter pylori
TTV
Prions
The mutations of traditional pathogens
Drug resistance became more severe
Mycobacterium tuberculosis
Department of Microbiology, Harbin Medical University
Importance
Most frequent diseases are infections
Mycobacterium: tuberculosis
Infectious hepatitis
HIV/AIDS
Coronavirus and SARS
Bird flu
Department of Microbiology, Harbin Medical University
Progress 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, 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)
Department of Microbiology, Harbin Medical University
Human Immunodeficiency Virus & AIDS
1981, the first case
report about AIDS
1983, HIV was isolated
1990s, HAART (cocktail
therapy) was employed
So far, no effective
vaccine available
www.health.howstuffworks.com
www.virology-online.com
Department of Microbiology, Harbin Medical University
HIV Genome
www.stanford.edu
Department of Microbiology, Harbin Medical University
Prions
Infectious proteins
Kuru
CJD
Mad cow disease
Scapie
1997 Nobel Prize
Prusiner
Department of Microbiology, Harbin Medical University
zeitgeist777
open your mind
Ebola virus
Department of Microbiology, Harbin Medical University
Transmission Route
Department of Microbiology, Harbin Medical University
http://www.cdc.gov/
Department of Microbiology, Harbin Medical University
Zika Time lines
1947
Scientists identify a new virus in a rhesus monkey in the Zika forest of Uganda - named as the Zika virus.
Department of Microbiology, Harbin Medical University
Pathogenecity
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus pneumoniae
Vibrio cholerae
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
Department of Microbiology, Harbin Medical University
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
Department of Microbiology, Harbin Medical University
Assessments
Participation
Quizzes & assignments
Final Examination
5%
10%
85%
Department of Microbiology, Harbin Medical University
Question
Classification of microorganisms
Koch’s Postulates
Department of Microbiology, Harbin Medical University
Web Resources PubMed: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=
PubMed
National Center for Biotechnological Information
http://www.ncbi.nlm.nih.gov
WHO: http://www.who.int/en/
US CDC: http://www.cdc.gov
UNAIDS: http://www.unaids.org/EN/default.asp
NIH:http://www.nih.gov
China CDC:http://www.chinacdc.net.cn
China Ministry of Health: http://www.moh.gov.cn
Department of Microbiology, Harbin Medical University
Some of the figures used in this chapter
have been collected from a variety of
media resources. Because of workload
is heavy, we did not make annotations
of all sources point-by-point.
If you have questions, contact ,e please.
Thank you for your understanding!