Introduction to MicrobiologyIntroduction to MicrobiologyIntroduction to MicrobiologyIntroduction to Microbiology

Maria Simatupang,drMaria Simatupang,drDept. of MicrobiologyDept. of Microbiologyp gyp gy

Medical FacultyMedical FacultyUSUUSU

Microbiology definedMicrobiology defined

• ‘The study of organisms, 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 0.2µmEl t i l ti b t 100 ti t– Electron microscope: resolution about 100 times greater

What is microbiology?

• Bacteriology• VirologyVirology• Mycology

I l• Immunology• Genetics

Comparison of medicaly important organisms

Characteristic Viruses Bacteria Fungi Protozoa&Helminth

C ll N Y Y YCells No Yes Yes YesDiameter(μm) 0.02-0.2 1-5 3-10 15-25

(yeast) (tropozoites)(yeast) (tropozoites)Nucl.acid either DNA both DNA both DNA both DNA

or RNA or RNA or RNA or RNA Type of nucleus none Prokaryotic Eukaryotic EukaryoticRibosomes - + + + Mitochondria - - + +oc o dOuter surce protein capsid peptidoglican chitin flexible

& lipoprotein envelope membraneMotility none some none noneMotility none some none noneMethod of not binary fission binary fission budding or mitosisReplication mitosis

The microbial world2 divisions Procaryotes& Eucaryotes

P t ( f• Procaryotes (refers mainly to the bacteria)

• No nucleus• No nucleus• Generally circular DNA

genome• +/- cell wall• Can have extrasomal

DNADNA• DNA without introns• Haploid (chromosome)• Haploid (chromosome)• Binary division

The 2nd microbial division

• Eucaryotes (includes parasites and fungi)

• Have nucleus• Other membrane

organellesorganelles• Diploid chromosomes• Mitotic & meiotic divisionMitotic & meiotic division• Have introns and exons

In clinical microbiology we have interest in both

• Bacteria (procaryotic)Eg Staph sp, Strep sp, E.coli, Mycoplasma spg p p p p y p p

• Fungi (eucaryotic)Candida sp (single celled yeast), Aspergillus sp (multicelled)p ( g y ), p g p ( )

• Parasites (eucaryotic)Giardia lamblia Plasmodium sp (malaria)Giardia lamblia, Plasmodium sp (malaria)

• VirusesHIV HBV HBC Rubella Herpes (EBV VZ HSV)HIV, HBV, HBC, Rubella, Herpes (EBV, VZ, HSV)

A little History

• Main events & people• Before about 1650 philosophers believed in• Before about 1650 philosophers believed in

“SPONTANEOUS GENERATION”

Si ifi t di i lt d thi thi kiSignificant discoveries altered this thinking.

S f h k lSome of the key players were:

ANTON van LEEUWENHOEK, 1674

• Mid 17th Century probably 1st to observe• Mid 17th Century probably 1st to observe bacteria under magnification

• Although Robert Hooke first to observe microbes through magnification It’s thought he saw protozoathrough magnification- It s thought he saw protozoaie larger cells such as amoebae

• Edward Jenner – 1796- First successful vaccinationvaccination.

• Relationship of cowpox to smallpox• Smallpox (virus)S a po (v us)

– 30-40% mortality• Viremia followed by death

ll i i Af i 19 6• Last naturally occurring case in Africa, 1976. • Role of WHO in smallpox eradication• Possible because humans are the only• 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, A d h i i d• And that air in does not create microbes

• Used broths in flasks and ‘S’• Used broths in flasks and S funneled microbial trap experiments

• Fermentation

• Pasteurization

• Joseph LISTER (1860)p ( )

• Adopted the use of 'aseptic' techniques which lead to its general adoptiong p

• ROBERT KOCH (1876)

• Proved beyond doubt that specificorganisms were the cause of specificg pinfectious diseases.

• Experiments with the very lethal disease• Experiments with the very lethal disease(especially of cattle) anthrax

Koch and wife1905-Nobel Prize

KOCH’S POSTULATESKOCH’S POSTULATES

• 1. The same 'pathogen' must be present in everycase of the diseasecase of the disease

• 2. The pathogen must be isolated from the diseased host and grown in pure culturediseased host and grown in pure culture

• 3. The pathogen when inoculated into asusceptible uninfected host causes the diseasesusceptible uninfected host causes the disease

• 4. The pathogen must be re-isolated in pureculture from the inoculated animalculture from the inoculated animal

• Griffith – 1928 – Experiment to determine which part of a pneumococcus bacteria caused the disease.

1944 G i i l i DNA h l• 1944 – Genetic material is DNA, not the capsule, not the cytoplasm. Provided the groundwork for A d M L d’ d fi iti k llAvery and McLeod’s definitive work, as well as for Watson and Crick (1953) DNA StructureStructure

• Fleming – 1929 – Penicillin (beta lactam ring in t l f b t i i i hibit d ki llouter layer of a bacteria is inhibited, making cell

wall synthesis impossible)

THANK YOUTHANK YOUTHANK YOUTHANK YOU