Biological and Biological and Physical SciencesPhysical Sciences

Principles of MicrobiologyPrinciples of Microbiology

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ObjectiveObjective

Identify the basics facts of microbiology in Identify the basics facts of microbiology in relation to Preventive Medicinerelation to Preventive Medicine

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OverviewOverviewDefinition Definition

CellsCells

Groups of MicroorganismsGroups of Microorganisms

Microbial GrowthMicrobial Growth

Role of Microorganisms Role of Microorganisms

Disease ProcessDisease Process

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Microbiology DefinitionMicrobiology Definition

Study of very small living organisms. Too small to be seen unaided Need a light microscope or

an electron microscope to see them

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Microbiology DefinitionMicrobiology Definition

Size comparisonSize comparison

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CellsCells

Smallest unit of living matter Smallest unit of living matter capable of independent lifecapable of independent lifeself-reproductionself-reproduction

Contains DNA and RNAContains DNA and RNA

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Types of Cells – Simple CellsTypes of Cells – Simple Cells

No nucleus/specialized organellesNo nucleus/specialized organelles

Genetic material on single circular chromosomeGenetic material on single circular chromosome

Cell wall is usually presentCell wall is usually present

chemically complexchemically complex gives cell shapegives cell shape has staining characteristicshas staining characteristics

Size ranges (1-10 um in diameter)Size ranges (1-10 um in diameter)

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Types of Cells-Complex CellsTypes of Cells-Complex Cells

Highly organizedHighly organized Specialized membrane Specialized membrane

boundbound Defined nucleusDefined nucleus

Genetic information-Genetic information-linear chromosomeslinear chromosomes

Cell wallCell wall May or may not be May or may not be

presentpresent Chemically simple when Chemically simple when

presentpresent

If present - Size range If present - Size range (10-100 um in diameter)(10-100 um in diameter)

Groups of Microorganisms Groups of Microorganisms Simple - BacteriaSimple - Bacteria

Size--0.20-2.0 um in diameter, 2-8 um in lengthSize--0.20-2.0 um in diameter, 2-8 um in length Three basic shapes--coccus, bacillus, spiralThree basic shapes--coccus, bacillus, spiral

Bacillus (rod)Coccus (round) Spiral

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Simple - BacteriaSimple - Bacteria

ShapesShapes

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Simple - BacteriaSimple - Bacteria

Staining characteristics--stains cell Staining characteristics--stains cell wallwall

Positive = purple = thick cell wall Negative = red/colorless = thin cell wall

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Simple - BacteriaSimple - Bacteria

Staining characteristicsStaining characteristics Provides information for treatment

different antibiotic therapies for gram positive vs.

gram negative bacteria

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AntibioticsAntibiotics

Substance that kill bacteria Substance that kill bacteria Many man-madeMany man-made

Most interfere with Most interfere with

cell wall formationcell wall formation

Adaptation “mutations”Adaptation “mutations”

by bacteria results in by bacteria results in

resistance

Testing antibiotics 13

EndosporesEndospores

Bacterial resting structures--survival mode Produced under adverse environmental conditions

High temperatures, no water, and toxic chemicals

Can remain dormant for years Important in food and medical care industries

resist normal processes used to kill bacteria

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Examples of BacteriaExamples of Bacteria Tuberculosis--Mycobacterium tuberculosis

Sexually Transmitted Diseases Neisseria gonorrhea -- Gonorrhea Chlamydia trachomatis -- Chlamydia Treponema pallidum -- Syphilis

M. Tuberculosis colonies

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Simple noncellular entities (parasite) Cannot reproduce by self (alone)

Can’t metabolize energy or proteins

Parasite--organism that derives its nutrients

from a living host without providing any benefit in return

Consist of either DNA or RNA--not both

Core surrounded by a protein coat (capsid)

Polio Virus

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VirusesViruses

VirusesViruses Size range (20-300 nanometers)

Smallest microorganisms

Multiply in cells of particular species Infect animals, plants, and bacteria

May or may not have an envelope

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Virus attaches to host cell

Releases genetic instructionsInto host cell

Recruits host cell’s enzymes

Assemble into new viruses

New viruses break free of host cell

VirusesViruses

VirusesVirusesCharacterized by shape

Helical, Polyhedral, Spherical, and Complex

Polyhedral (many sided)

Helical (coiled tubes)

Complex (combination)

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Examples of Viral DiseasesExamples of Viral DiseasesInfluenza--Respiratory InfectionHIV--Bloodborne and Sexually TransmittedHepatitis B--Hepatic (Liver) Infection

HIVInfluenza Virus

Budding out of a human immune cell

Hepatitis B Virus

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Complex MicroorganismsComplex Microorganisms- Fungi- Fungi

Unicellular (yeasts) or multicellular (mushrooms) Plantlike, but cannot photosynthesize Absorb nutrients from environment Decompose organic material Some are parasites of plants and animals Examples

Yeasts Molds

Penicillin mold 21

Harmful Effects of FungiHarmful Effects of FungiEconomic Effects

Molds cause spoilage--fruits, vegetables, grains Cause diseases in plants--wheat, potatoes, elms

Diseases Caused by Fungi Infections of hair, skin, and internal organs Foodborne illnesses (rare)--aflatoxins in peanuts

Ringworm 22

Harmful Effects of FungiHarmful Effects of Fungi

Diseases Caused by Fungi

Fungal foot

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Complex Microorganisms - Complex Microorganisms - ProtozoaProtozoa

Found in soil, water, intestinal tracts of animalsFound in soil, water, intestinal tracts of animals Size range (3-100 um)Size range (3-100 um)

Unicellular animalsUnicellular animals

Classified by means of movementClassified by means of movement Flagellates--long, whiplike extensionsFlagellates--long, whiplike extensions Ciliates--shorter hairlike extensionsCiliates--shorter hairlike extensions Pseudopodia--blunt, lobe-like projectionsPseudopodia--blunt, lobe-like projections

Some are incapable of movement--must beSome are incapable of movement--must be

carried/transported--plasmodium causes malariacarried/transported--plasmodium causes malaria

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ProtozoaProtozoa Cysts are produced under adverse conditions

for survival outside a hostLack of nutrients, water, and oxygenTemperatures aren’t suitable

Presence of certain toxic chemicals

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Protozoal DiseasesProtozoal Diseases

Amoebic Dysentery•Amoebae feeds on red blood cells•Human-to-human transmission through cysts passed through feces to mouth (ingestion)

Giardiasis•Parasite found in small intestine of mammals•Cyst can survive in environment until ingested

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Protozoal DiseasesProtozoal Diseases

Malaria--Plasmodium vivaxMalaria--Plasmodium vivax Complex life cycleComplex life cycle Involves red blood cells, liver of humans, andInvolves red blood cells, liver of humans, and

intestinal tract of female mosquitoesintestinal tract of female mosquitoes

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Complex Microorganisms Complex Microorganisms - Algae- Algae

Pigmented plants Unicellular or multi-cellular Photosynthesize--converts CO2 to O2

Mostly aquatic Prefer lots of light (radiant energy)

Example: Red Tides (Red Algae Gonyaulax) Produce toxin that causes paralytic shellfish

poisoning

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Microbial GrowthMicrobial GrowthPhysical RequirementsPhysical Requirements

Physical AspectsPhysical AspectsLight, temperature, and pHLight, temperature, and pHMay be less stringent for survival vs. May be less stringent for survival vs.

growthgrowth

Chemical AspectsChemical AspectsWater, carbon, oxygen, and other Water, carbon, oxygen, and other

mineralsminerals29

Physical - LightPhysical - Light

Light-Energy SourceLight-Energy Source PhotosynthesisPhotosynthesis

Light used as an energy sourceLight used as an energy source

Exposure to direct sunlight can killExposure to direct sunlight can kill UV light used on TB bacteriaUV light used on TB bacteria

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Physical - TemperaturePhysical - Temperature

Based on preferred rangeBased on preferred range Mesophiles (moderate loving microbes)Mesophiles (moderate loving microbes)

202000- 40- 4000 C/68 C/6800 – 104 – 10400FFMost pathogensMost pathogens

Thermophiles (heat loving microbes)Thermophiles (heat loving microbes)Above 45Above 4500C/113C/11300FFspoilage organismsspoilage organisms

Psychrophiles (cold loving microbes)Psychrophiles (cold loving microbes)0000- 20- 2000C/30 - 68C/30 - 6800FFSpoilage in refrigerationSpoilage in refrigeration

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Physical – pH levelPhysical – pH level

pH--refers to alkalinity or acidity in solution Best growth in pH 6.5 - 7.5 (neutral range) Few grow in acid pH below 4.0

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Chemical - WaterChemical - Water

Water--microorganisms are 80-90% waterWater--microorganisms are 80-90% water Hydrophilic--need lots of moisture for growthHydrophilic--need lots of moisture for growth Hydrophobic--grow best with little wHydrophobic--grow best with little waterater

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Chemical - CarbonChemical - Carbon

CarbonCarbon Some microorganisms Some microorganisms

rely on carbon dioxide rely on carbon dioxide as source of carbonas source of carbon

Other microorganisms Other microorganisms use organic material as use organic material as source of carbonsource of carbon

Chemical - OxygenChemical - Oxygen

Aerobic--need oxygen to --need oxygen to livelive

AnaerobicAnaerobic--live without --live without oxygenoxygen

FacultativeFacultative--anaerobes --anaerobes that survive with that survive with

or without oxygenor without oxygen Obligate anaerobes-Obligate anaerobes-

die when exposed to die when exposed to

oxygenoxygen

Control of Microbial GrowthControl of Microbial Growth

Bacteria grow FAST! Bacteria grow FAST! • In ideal circumstances, some common In ideal circumstances, some common

bacterial cells can divide and double every 20 bacterial cells can divide and double every 20 minutes minutes

Control of Microbial GrowthControl of Microbial Growth

PhysicalPhysical Heat, cold, drying, and radiationHeat, cold, drying, and radiation

Chemical MethodsChemical Methods Destroy or limit growth on body surfacesDestroy or limit growth on body surfaces

SterilizationSterilization Destruction of all microorganismsDestruction of all microorganisms Both physical and chemical controlBoth physical and chemical control

RadiationRadiation

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Physical Methods - HeatPhysical Methods - Heat Most practical, efficient and inexpensiveMost practical, efficient and inexpensive Time and temperatureTime and temperature TypesTypes

Boiling (100Boiling (10000C) - kills most cells and viruses C) - kills most cells and viruses within 10 minuteswithin 10 minutes

Pasteurization – high temperature/short timePasteurization – high temperature/short timeAutoclaving – steam under pressureAutoclaving – steam under pressureDry Heat – direct flame, incinerationDry Heat – direct flame, incineration

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Physical Methods - ColdPhysical Methods - Cold

RefrigerationRefrigeration (0 (000-7-700C)--inhibits growthC)--inhibits growth Slows most microbial growth Slows most microbial growth But may But may Not Kill Not Kill themthem

FreezingFreezing--No growth or reproduction, but --No growth or reproduction, but may still survive!may still survive!

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Physical Methods - DryingPhysical Methods - Drying

Without water, cannot grow, but may liveWithout water, cannot grow, but may live

Curing--High concentration of salt and sugar Curing--High concentration of salt and sugar results in loss of water (dehydration)results in loss of water (dehydration)

Freeze drying--removes water by high vacuum Freeze drying--removes water by high vacuum at low temperaturesat low temperatures

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Physical Methods - RadiationPhysical Methods - Radiation

Non-ionizing radiation-Non-ionizing radiation--low penetration -low penetration used on surfaces / in the air (UV light)used on surfaces / in the air (UV light)

Ionizing radiationIonizing radiation Sterilize pharmaceuticals, and Sterilize pharmaceuticals, and

medical/dental instrumentsmedical/dental instruments Used in foods (generally not Used in foods (generally not

accepted by public)accepted by public)

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Chemical Methods Chemical Methods of Controlof Control

Disinfection--process that --process that destroys, neutralizes, or inhibits destroys, neutralizes, or inhibits pathogenic organismspathogenic organisms

DisinfectantDisinfectant--chemical agent --chemical agent used on inanimate objects to used on inanimate objects to destroy pathogens, but not destroy pathogens, but not necessarily viruses or necessarily viruses or endosporesendospores

AntisepticAntiseptic--chemical agents --chemical agents used on living tissueused on living tissue

Sanitation Sanitation – reduce to safe – reduce to safe levelslevels

Few chemicals Few chemicals achieve sterilityachieve sterility

Staphylococcus aureus

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Chemical Methods - TypesChemical Methods - Types

Halogens Halogens -- used alone or combined in solution-- used alone or combined in solution IodineIodine--inactivates enzymes and other cellular proteins--inactivates enzymes and other cellular proteins ChlorineChlorine--acidifies environment--acidifies environment

Soaps and DetergentsSoaps and Detergents Decrease surface tension--aids in mechanical removal of Decrease surface tension--aids in mechanical removal of

microorganismsmicroorganisms HandwashingHandwashing---most important means for preventing-most important means for preventing

transfer of microorganisms transfer of microorganisms

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Chemical Methods - Principles of Chemical Methods - Principles of DisinfectionDisinfection

Properties and Concentration of chemical used Properties and Concentration of chemical used (Read the instructions!!)(Read the instructions!!)

Presence of organic matter (May need additional Presence of organic matter (May need additional scrubbing)scrubbing)

Temperature (hotter= more effective)Temperature (hotter= more effective)

Role of microorganism (positive or negative)Role of microorganism (positive or negative)

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Positive Roles Positive Roles

Microorganisms are beneficial to humansMicroorganisms are beneficial to humans Degrade dead plants and animalsDegrade dead plants and animals Recycle chemical elements used by living cellsRecycle chemical elements used by living cells

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Positive Roles Positive Roles Useful in food production--cheese and yogurtUseful in food production--cheese and yogurt Industry--insulin, vaccines, antibiotics, and Industry--insulin, vaccines, antibiotics, and

bioremediation for pollutantsbioremediation for pollutants

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Positive Roles Positive Roles Living animals have Living animals have normal floranormal flora

““Normal flora” Normal flora” are microorganisms that are microorganisms that

colonize an animal without causing diseasecolonize an animal without causing disease Compete with pathogenic microorganismsCompete with pathogenic microorganisms

Normal skin flora

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How Microorganisms Cause How Microorganisms Cause DiseaseDisease

Pathogenicity Pathogenicity – ability to produce disease– ability to produce disease 10% of microorganisms are opportunists --10% of microorganisms are opportunists --

cause disease under specific circumstancescause disease under specific circumstances 3% of microorganisms are true pathogens3% of microorganisms are true pathogens

Virulence Virulence – degree of pathogenicity– degree of pathogenicity

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How Microorganisms Cause How Microorganisms Cause DiseaseDisease

Virulence -- degree of pathogenicityVirulence -- degree of pathogenicity Infectivity Infectivity -- ability to enter host and avoid host -- ability to enter host and avoid host

defensesdefenses

InvasivenessInvasiveness -- ability to enter tissue of a host and -- ability to enter tissue of a host and flourishflourish

Toxigenicity Toxigenicity -- ability of microorganism to produce a -- ability of microorganism to produce a poisonpoison ExotoxinsExotoxins--produced by bacteria and released--produced by bacteria and released EnterotoxinsEnterotoxins--toxins that act on intestinal cells--toxins that act on intestinal cells

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Disease ProcessesDisease Processes

Exposure to organismExposure to organism Incubation Period -- No SymptomsIncubation Period -- No Symptoms

Microorganism multiplies and overcomes host Microorganism multiplies and overcomes host defensedefense

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Disease ProcessesDisease Processes

IllnessIllness -- presence of signs/symptoms -- presence of signs/symptoms Local infection -- pathogen is confined to single Local infection -- pathogen is confined to single

areaarea Systemic infection -- pathogen invades tissues Systemic infection -- pathogen invades tissues

and/or is carried by lymphatic and/or circulatory and/or is carried by lymphatic and/or circulatory system throughout bodysystem throughout body

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Disease ProcessesDisease Processes

IllnessIllness Disease may be acute, chronic, or bothDisease may be acute, chronic, or both

AcuteAcute--rapid onset followed by rapid recovery--rapid onset followed by rapid recovery

ChronicChronic--slow onset, long duration--slow onset, long duration BothBoth--rapid onset followed by long-lasting disease --rapid onset followed by long-lasting disease

processprocess

Recovery, Disability, or DeathRecovery, Disability, or Death

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NATURAL COURSE OF DISEASE

Stage of Stage of Stage of Stage of Stage of Stage of Stage of Stage of RecoveryRecoverySusceptibility Subclinical Disease Clinical Disease Disability or DeathSusceptibility Subclinical Disease Clinical Disease Disability or Death

Pathologic Pathologic Onset ofOnset of Exposure Changes SymptomsExposure Changes Symptoms

Usual TimeUsual Timeof Diagnosisof Diagnosis

Incubation PeriodIncubation Period

ObjectiveObjective

Identify the basics facts of microbiology in Identify the basics facts of microbiology in relation to Preventive Medicine.relation to Preventive Medicine.

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SummarySummaryDefinition Definition

CellsCells

Groups of MicroorganismsGroups of Microorganisms

Microbial GrowthMicrobial Growth

Role of Microorganisms Role of Microorganisms

Disease ProcessDisease Process

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QUESTIONS?QUESTIONS?

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