bbs2 mb k1 pendahuluan mikrobiologi
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INTRODUCTION TO INTRODUCTION TO MICROBIOLOGYMICROBIOLOGY
Department of MicrobiologyDepartment of MicrobiologyMedical Faculty USUMedical Faculty USU
Spesific Learning Objectives
1. Menjelaskan asal usul mikroorganisme
2. Menyebutkan tokoh/perintis dalam bidang mikrobiologi
3. Menyebutkan kaidah mikroba sebagai penyebab penyakit (Postulat Koch)
4. Menjelaskan perbedaan dan perbandingan sifat virus, bakteri, jamur, chlamydia dan ricketsia
REFERENCES
JAWETZ, MELNICK & ADELBERG’S MEDICAL MICROBIOLOGY, 24TH EDITION by Geo. F. Brooks, Karen C. Carroll, Janet S. Butel, and Stephen A. Morse, McGraw-Hill, 2007.
MIKROBIOLOGI KEDOKTERAN, Edisi Revisi, Pengarang Staf Pengajar FK UI, Binarupa Aksara.
REFERENCES
Lippincott’s Illustrated Reviews Microbiology 2nd edition by Richard A. Harvey, Pamela C. Champe, Bruce D. Fisher, 2007, Lippincott Williams & Wilkins.
MEDICAL MICROBIOLOGY by FH Kayser, K.A. Bienz, J. Eckert, R.M.Zinkernagel, Thieme, 2005.
Microbiology defined
‘The study of microorganisms, where the individual cells of the 'microbe' can't be seen by the
unaided human eye'
That is, we need to use specialized detection systems-usually optical instruments termed microscopes.
There are 2 main type main types of microscopes in use:
- Bright field microscope resolution about 0.2µm
- Electron microscope resolution about 100 times greater
What is microbiology?
Bacteriology Virology Mycology Immunology Genetics
Virus
Contain only one type of nucleic acid, either DNA or RNA
No enzymatic energy producing system No protein synthesizing apparatus Force infected host cells to synthesize
virus particles
Comparison of prokaryotic and eukaryotic cellsCharacteristic Prokaryotic cells Eukaryotic cells
Chromosome Single, circular Multiple
Nucleus No nuclear membrane or nucleoli
Membrane-bound, nuceoli present
Membrane-bound organelles
Not present Present (examples include mitochondria and endoplasmic reticulum)
Cell wall Usually present, many contain peptidoglycan
Present in plant cells, no peptidoglycan
Plasma membrane No carbohydrates, most lack sterols
Sterol and carbohydrates present
Ribosome 70S 80S
Average size 0,2-2 µm in diameter 10-100 µm in diameter
Replication Binary fission Budding or mitosis
Procaryotes
Procaryotes (refers mainly to the bacteria)
No nucleus Generally circular DNA
genome +/- cell wall Can have extrasomal
DNA DNA without introns Haploid (chromosome) Binary division
BACTERIA
Classic bacteria.
Reproduce asexually by binary transverse fission.
Do not possess the nucleus typical of eucarya.
The cell walls of these organisms are rigid (with some exceptions, e.g., the mycoplasma).
ATYPICAL BACTERIA
Chlamydiae Obligate intracellular parasites that are
able to reproduce in certain human cells only.
Found in two stages: the infectious, nonreproductive particles called elementary bodies (0.3 lm) and the noninfectious, intracytoplasmic, reproductive forms known as initial (or reticulate) bodies (1 lm).
ATYPICAL BACTERIA
Rickettsiae Obligate intracellular parasites. Rodshaped to coccoid. Reproduce by binary transverse fission. The diameter of the individual cell is from
0.3–1 lm.
Eucaryotes Eucaryotes (include
fungi, protozoa, helminth)
Have nucleus Other membrane
organelles Diploid chromosomes Mitotic & meiotic
division Have introns and exons
In clinical microbiology we have interest in both
Bacteria (procaryotic)Eg Staph sp, Strep sp, E.coli, Mycoplasma sp
Fungi (eucaryotic)Eg Candida sp (single celled yeast), Aspergillus sp (multicelled)
Parasites (eucaryotic)Eg Giardia lamblia, Plasmodium sp (malaria)
Viruses
Eg HIV, HBV, HBC, Rubella, Herpes (EBV, VZ, HSV)
A little History
Before about 1650 philosophers believed in
“SPONTANEOUS GENERATION”
Significant discoveries altered this thinking.
Some of the key players were:
ANTON van LEEUWENHOEK, 1674
Mid 17th Century probably 1st to observe
bacteria under magnification
Although Robert Hooke first to observe microbes through magnification- It’s thought he saw
protozoa(larger cells such as amoebae)
Edward Jenner, 1796 First successful vaccination
Relationship of cowpox to smallpox Smallpox (virus) 30-40% mortality Viremia followed by death Last naturally occurring case in Africa,
1976 Role of WHO in smallpox eradication Possible because humans are the only
smallpox host.
LOUIS PASTEUR:
Demonstrated by the use of sterile media that microbes were in fact present in air
And that air does not create microbes
Used broths in flasks and ‘S’ funneled microbial trap experiments
Fermentation
Pasteurization
Joseph LISTER (1860)
Adopted the use of 'aseptic' techniques which lead to its general adoption
ROBERT KOCH (1876)
Proved beyond doubt that specific
organisms were the cause of specific
infectious diseases.
Experiments with the very lethal disease
(especially of cattle) anthraxKoch and wife1905-Nobel Prize
KOCH’S POSTULATES
1. The same 'pathogen' must be present in every case of the disease
2. The pathogen must be isolated from the
diseased host and grown in pure culture
3. The pathogen when inoculated into a
susceptible uninfected host causes the disease
4. The pathogen must be re-isolated in pure
culture from the inoculated animal
Griffith – 1928 – Experiment to determine which part of a pneumococcus bacteria caused the disease.
1944 – Genetic material is DNA, not the capsule, not the cytoplasm. Provided the groundwork for Avery and McLeod’s definitive work, as well as for Watson and Crick (1953) DNA Structure
Fleming – 1929 – Penicillin (beta lactam ring in outer layer of a bacteria is inhibited, making cell wall synthesis impossible)