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)