2. Scope of MicrobiologyScope of Microbiology
 MicrobiologyMicrobiology
 Micro: Small, Bio: Live, Logy: ScienceMicro: Small, Bio: Live, Logy: Science
 Study of organisms too small to be seen byStudy of organisms too small to be seen by
the naked eye.the naked eye.
 MicroorganismsMicroorganisms
 Bacteria, viruses, fungi, algae, protozoaBacteria, viruses, fungi, algae, protozoa
and helminthes.and helminthes.

3. Branches of StudyBranches of Study
 BacteriologyBacteriology Study of bacteriaStudy of bacteria
 MycologyMycology Study of fungi and yeastStudy of fungi and yeast
 VirologyVirology Study of virusesStudy of viruses
 ParasitologicalParasitological Study of parasitic protozoan andStudy of parasitic protozoan and
helmintheshelminthes
 ImmunologyImmunology Study of the humoral and cellularStudy of the humoral and cellular
immune response to diseaseimmune response to disease
agents and allergensagents and allergens

4. Importance of MicrobiologyImportance of Microbiology
 First bacteriaFirst bacteria
 Photosynthesis and decompositionPhotosynthesis and decomposition
 Human use of microorganismsHuman use of microorganisms
 Infectious diseasesInfectious diseases

5. Modern Uses of MicrobesModern Uses of Microbes
 Biotechnology:Biotechnology: Production of food and chemicalsProduction of food and chemicals
 Genetic engineering:Genetic engineering: Molecular biology andMolecular biology and
recombinant DNA techniquesrecombinant DNA techniques
 Gene therapy:Gene therapy: Replaces missing or defectiveReplaces missing or defective
genes in human cells through genetic engineering.genes in human cells through genetic engineering.

6. Infectious DiseasesInfectious Diseases
Worldwide infectious disease
statistics
 United States Public Health
Service (USPHS) - agency
where notifiable diseases are
reported
 Centers for Disease Control
(CDC)-collects disease data
around the U.S. and publishes
the MMWR (Morbidity and
Mortality Weekly Report)
 World Health Organization
(WHO)-medical arm of the U.N.,
monitors diseases worldwide.

7. Microbial TaxonomyMicrobial Taxonomy
Traditional Whittaker 5 Kingdom
System

8. Microbial TaxonomyMicrobial Taxonomy
Woese-Fox 3 Domain System

9. NomenclatureNomenclature
 Each organism has two names: the genus andEach organism has two names: the genus and
speciesspecies
 Italicized or underlineItalicized or underline
 Genus name is capitalized and species in lowerGenus name is capitalized and species in lower
case.case.

10. Scientific NamesScientific Names
Staphylococcus aureusStaphylococcus aureus
Describes clustered arrangement of cells andDescribes clustered arrangement of cells and
golden yellow color of coloniesgolden yellow color of colonies
Escherichia coliEscherichia coli
Honors the discoverer, Theodor EscherichiaHonors the discoverer, Theodor Escherichia
and describes its habitat, the colon.and describes its habitat, the colon.
After the first use, scientific names may beAfter the first use, scientific names may be
abbreviated with the first letter of the genusabbreviated with the first letter of the genus
and full letters of the species (Ex:and full letters of the species (Ex: E. coliE. coli))

11. General CharacteristicsGeneral Characteristics
 ProkaryotesProkaryotes
 EukaryotesEukaryotes
 A cellular agentsA cellular agents Genomes contain eitherGenomes contain either
DNA or RNA; e.g. Virus,DNA or RNA; e.g. Virus,
newer agent is proteinaceousnewer agent is proteinaceous

12. Differences between prokaryotes and eukaryotesDifferences between prokaryotes and eukaryotes
Prokaryotes Eukaryotes
Cell size 0.2-2micrometer
In diameter
10-100micrometer
In diameter
Nucleus No nuclear membrane or
nucleoli (nucleoid)
True nucleus, consisting of
nuclear membrane &
nucleoli
Cell Division Binary Fission Mitosis
Cell wall Usually present;
chemically complex
(typical bacterial cell wall
includes peptidoglycan)
When present, chemically
simple

13. Cell TypesCell Types
Comparative Cellular Structures of Microbes

14. The MicrobesThe Microbes
Viruses Protozoa
Bacteria
Bacteriophage
Algae
Spirochaetes
Cyanobacteria
Fungi

15. Size of MicrobesSize of Microbes
Microbes vary in size
ranging from 10 nm
(nanometers) to 100 mu
(micrometers) to the
macroscopic.
Viruses in nm = 10-9
m
(meter)
Bacteria in um = 10-6
m
Helminths in mm = 10-3
m

16. BacteriaBacteria
 Prokaryotes
 Peptidoglycan cell walls
 Binary fission
 Eg., Escherichia coli

17. FungiFungi
 Eukaryotes
 Chitin cell walls
 Molds and mushrooms
are multicellular
 Yeasts are unicellular

18. ProtozoaProtozoa
 Eukaryotes
 Mostly saprobes and commensals
 May be motile by means of
pseudopod, cilia or flagella

19. HelminthesHelminthes
 Eukaryotes
 Multicellular animals
 Parasitic flatworms and roundworms
called helminthes
 Microscopic stages in life cycles

20. AlgaeAlgae
 Eukaryotes
 Cellulose cell walls
 Photosynthetic
 Produce molecular oxygen and
organic compounds
 Part of food chain

21. VirusesViruses
 A cellular
 Obligate intracellular parasites
 Genome consist of DNA or RNA
 Surrounded by protein coat
 May be enclosed in lipid envelope

22. The First MicroscopeThe First Microscope
Microbes were first
observed by Antonie
van Leeuwenhoek
using a simple
microscope (ca. 1673)
Reported his
“animalcules” to the
Royal Society of
London

23. Spores and SterilizationSpores and Sterilization
 John Tyndall:John Tyndall: Some microbes in dust andSome microbes in dust and
air were resistant to heatair were resistant to heat
 Ferdinand Cohn:Ferdinand Cohn: Discovered and describedDiscovered and described
endosporesendospores
 Sterile:Sterile: Complete removal of all life formsComplete removal of all life forms
including endosporesincluding endospores

24. Louis PasteurLouis Pasteur
 Microbes causedMicrobes caused
fermentationfermentation
 Pasteurization:Pasteurization: PreventPrevent
spoilagespoilage

25. Antiseptics and Hand WashingAntiseptics and Hand Washing
 1860s:1860s: Joseph Lister:Joseph Lister: Used, carbolicUsed, carbolic
acid, a chemical antiseptic to preventacid, a chemical antiseptic to prevent
surgical wound infectionssurgical wound infections
 Ignaz Semmelweis:Ignaz Semmelweis: Introduced handIntroduced hand
washing as a means of preventing transferwashing as a means of preventing transfer
of puerpueral sepsis in obstetrical patientsof puerpueral sepsis in obstetrical patients

26. Infection and DiseaseInfection and Disease
 Infection:Infection: Entry of a microbe into the hostEntry of a microbe into the host
 Disease:Disease: Appearance of signs and symptomsAppearance of signs and symptoms
 Pathogen:Pathogen: An infectious agentAn infectious agent
 Opportunistic pathogen:Opportunistic pathogen: A microbe thatA microbe that
cause disease in immuno compromised hosts orcause disease in immuno compromised hosts or
when the normal microbiota is alteredwhen the normal microbiota is altered