39047609 Fundamentals of Bioaerosol BJ

7/27/2019 39047609 Fundamentals of Bioaerosol BJ

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JayachelviBabu

Bioaerosoly Bioaerosolsaredefinedasairborneparticlesthatarelivingororiginate

fromlivingorganisms.Suchasmetabolites,toxinsorfragmentsofmicroorganisms.

Bacteria,virusesandFungiy Bioaerosolsarerespirablesize

Viruses 0.003mBacteria 0.5to20mPlantpollens 10 to100mMolds 2 to 200m

Bacteriay Abundantintheenvironmentandhumans.

y Morethan150,000knownspeciesofbacteria

y Singlecelled,reproducedbysimplecelldivisioncallednary ss on.


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Stainedpreparationy Livebacteriadonotshowmuchstructuraldetailunderthe

lightmicroscopeduetolackofcontrast,tousestainingtechniquetoproducecolourcontrast.

StainingTechniquey SimpleStains

y Negativestaining

y Impregnationmethod

y Differentialstains

Gramstain

Meth lene blueorGentianviolet

DiluteIodinesolution

Acetone(Decolorizingagent

Safranine orDilutecarbol fuchsin

Theyaredividedintotwomajorgroupsbasedontheirreactionto

Gramstain,theyare GrampositiveandGramnegativebacteria(basisofcellular,morphologicalorbiochemicalcharacteristics)

Mycobacteriumtuberculaey Acidfaststain:Ziehl

andNeelsenmethod StrongCarbolfuchsin

20%Sulphuricacid

staining)


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ShapeofBacteriay Cocci:Sphericalorovalcells

y Bacilli:Rodshapedcells

y Vibrios:Commashaped,curvedrods

y Spirilla:Rigidspiralforms

y Spirocheates:Spiracoil/chaitehair

y Actinomycetes:Branchingfilamentousbacteria

y Mycoplasma:Cellwalldeficient,donotpossessastablemorphology.

Arrangements

y Cocci:

pairs Diplococci,Chains Streptococci

four Tetrads,Eight Sarcina,orasgrapelikeclusters stap y ococc .

y Bacilli:Diplobacilli,streptobacilli.


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GrowthRequirementsofBacteriay Suitable nutrients: carbon and energy source, nitrogen source,

inorganic salts, organic compounds

Phototrophs Derive the energy from sunlightChemotrophs Obtain the energy from chemical reaction

Heterotrophs unable to synthesis their own metabolites anddepend on performed organic compounds

OxygenRequirementsofbacteriay Dependingontheinfluenceofoxygenongrowth

andviability,bacteriaaredividedintotwogroups.

Aerobicbacteria:Requireoxygenforgrowth.

Anaerobicbacteria:Growintheabsenceofoxygen(dieonexposuretooxygen)

Microaerophilicbacteria:Growbestinthepresenceofalowoxygentension.

GrowthRequirementsofBacteriay Physical conditions

carbon dioxide

temperature

moisture and desiccation

hydrogen ion concentration

light and other radiations

mechanical stress

MoldsandYeastsy Fungiareubiquitousintheenvironment

y Saprophytes,meaningthattheyusedeadorganicmaterialasasourceofnutrientsfortheirgrowth

.

y Severalliveinthesoilandtakeanactivepartinthedecompositionoforganicmaterial.Theyaregenerallyaerobic.

y Wellproliferateinhumidindoorenvironment

y Humancommonly

exposed

to

more

than

200

species.


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y Yeastsaresinglecellorganismsthatdividebyfissionandbudding.

y Moldsaremulticelledandtheypropagatebyspores.

y pores er n orm,s zean co our.

y Theycansurvivefromafewdaystoseveralyears.

FungiColoniesFungiColonies

AspergillusfumigatusSporesSpores

(Conidia)(Conidia)

Virusy Avirus isamicroscopic infectiousagentthatcan

reproduceonlyinsideahost cell.Virusesinfectalltypesoforganismsfromanimals andplants,tobacteria.Virusesareubi uitous asthe arefoundinalmosteveryecosystem onEarth.Thestudyof

virusesisknownasvirology,andisabranchofmicrobiology.


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y Notallvirusescausedisease,asmanyvirusesreproducewithoutcausinganyobviousharmtotheinfectedorganism.

y Immuneresponsescanalsobeproducedbyvaccines thatgivelifelongimmunitytoaviralinfection.

y Microorganismssuchasbacteriaalsohavedefensesagainstviral.

y Antibiotics havenoeffectonviruses,butantiviraldrugs havebeendevelopedtotreatbothlifethreateningandmoreminorinfections.

Modeofinfectiony Inhalation

y Ingestion

y Dermalexposure

DepositionofMicroorganisms1: Nasopharynx or Head

Deposition > 20 m

2: Larynx, Trachea, Bronchi

Deposition < 20 m

3: Bronchioles and Alveoli

Deposition < 1 - 4 m

Inhalationy Respiratoryinfectionssuch

asinfluenzaandtuberculosisaretransmittedbyinhalationofthe atho ens.

y Pathogensresistanttodryingmayremainviableinthedustandactassourceofinfection.


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Ingestiony Intestinalinfectionsaregenerallyacquiredbythe

ingestionoffoodordrinkcontaminatedbypathogens

y ater orne C o era

y Foodborne(Salmonella,foodpoisoning)

y Handborne/Fingerborne(Notonlymouth,butalsoenterthroughthenoseandeyes)

Dermalexposurey Pathogensdirectlyentersintothetissuesofthe

host.

y Tetanussporesimplantedindeepwounds

y Rabiesvirusdepositedsubcutaneouslybydogbite

y Unsterilesyringesandsurgicalequipments

y HIV,HepatitisBtransmittedthroughtransfusionofinfectedblood.

Pathogenisityy Pathogenisityreferstotheabilityofamicrobeto

producediseasesortissueinjury.

y ox gen s ty: acter apro ucetwotypeso tox nsexotoxinsandendotoxins.

Exotoxins

y Exotoxinsaregenerallyformedbygrampositivebacteria.

y Exotoxinsareheatlabileproteinsanddiffusereadilyintothesurroundingmedium.

,botulinumtoxinssufficienttokillmorethanonemillionguineapigsandithasbeenestimatedthat3kgofbotulinumtoxinscankillalltheinhabitantsoftheworld.


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Endotoxins

y Endotoxinsareheatstablelipopolysaccharides(LPS)whichformanintegralpartofthecellwallofgramnegativebacteria.

y Administrationofsmallquantities ofendotoxinsinsuscept ean ma scausesane evat ono o ytemperaturemanifestedwithin15minutesandlastingforseveralhours

y Intravenousinjectionoflargedosesofendotoxinsandmassivegramnegativesepticemiascauseendotoxicshockmarkedbyfever,leucopenia,thrombocytopenia,significantfallinbloodpressure,circulatorycollapseandbloodydiarrhealeadingtodeath.

Mycotoxinsy Mycotoxins:Duringthenutrientdegradationprocess,moldsrelease

secondarymetabolitescalledmycotoxinsthattheyusedasadefenseagainstothermicroorganismsincludingothermolds.

y yco ox nsarenonvo a ecompoun san w e oun n ea r.

y ItcauseSkinandmucousmembraneirritation,immunosuppression,dizziness,nausea,headacheandneuropsychologicaleffects.

y Somemycotoxinssuchasaflatoxinareconsideredcarcinogenic;theingestionofaflotoxiniaaknowncauseoflivercancer.

SterilizationandDisinfectiony Sterilizationisdefinedastheprocessbywhichan

article,surfaceormediumisfreedofalllivingmicroorganismseitherinthevegetativeorsporestate.

y Disinfectionmeansthedestructionorremovalofallpathogenicorganisms,ororganismscapableofgivingrisetoinfection.

y Antisepsisisusedtopreventionofinfection,

usuallyby

inhibiting

the

growth

of

bacteria

in

woundsortissues.

y BactericidalagentsorGermicidesarethosewhichareabletokillbacteria

y Decontaminationreferstotheprocessofrenderingan,

includingmicrobial,chemical,radioactiveandotherhazards.


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PhysicalAgentsy Sunlight

y Drying

y Dryheat:Flaming,incineration,hotair

y o s ea : as eur za on, o ng,s eamun ernormapressure,steamunderpressure.

y Filtration:Candles,asbestospads,membranes

y Radiation

y Ultrasonicandsonicvibration.

Sunlighty Sunlightpossesappreciablebactericidalactivityand

playsanimportantroleinthespontaneoussterilizationthatoccursundernaturalconditions.

andheatrays.

Dryingy Moistureisessentialforgrowthofbacteria

y Dryinginairhasdeleteriouseffectonmanybacteria

y Sporesareunaffectedbydrying.

Heat

DryHeaty Flaming:Inoculatinglooporwire,thetipofforcepsand

searingspatulasareheldinaBunsenflametilltheybecomeredhot.

y Incineration:Thisisanexcellentmethodforsafel destroyingmaterialssuchascontaminatedcloth,animalcarcasses,andpathologicalmaterials.

y Hotairoven:Thisisthemostwidelyusedmethodofsterilizationbydryheat.Aholdingperiodof160C.forone

hr.

is

used

to

sterilize

glassware,

forceps,

scissors,

scalpels,

allglasssyringes,swabs.


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MoistheatTemperaturebelow100C(Pasteurizationof milk)

Themilkisheatedateither63cfor30min.(theholdermethod)or72cfor1520seconds(theflashprocess)followedb coolin uickl to1 corlower.

Nonsporingpathogenssuchasmycobacteria,brucellae,andslmonellaaredestroyed.

Temperatureat100CBoiling:Vegetativebacteriaarekilledalmostimmediatelyat

90100c

Moistheaty Steamatatmosphericpressure(100c):

Asingleexposureofninetyminutesusuallyensuressterilizationbutformediacontainingsugarsorgelatinanexposureof100cfor20minutesonthesesuccessivedaysisused.ThisisknownasTyndallisationorintermittentsterilization.

y Steamunderpressure:Sterilizationbysteamunderpressureiscarriedoutat

temperaturebetween108cand147c.byusingtheeappropriatetemperatureandtime,avarietyofmaterialsuchasdressings,instruments,laboratoryware,mediaanspharmaceuticalproductscanbesterilized.

Filtration

Filtrationhelpstoremovebacteriafromheatlabileliquidssuchasseraandsolutionsofsugarsorantibioticsusedforpreparationofculturemedia.

Asbestosfilters

Sinteredglassfilters

Membranefilters

Radiation

Nonionisingradiation:y Infraredradiationisusedforrapidmass

sterilizationofprepackeditemssuchassyringesandcatheters

y Ultravioletradiationisusedfordisinfectingenclosedareassuchasentryways,operationtheatersandlaboratories.


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RadiationIonizingradiation:y Xrays,gammaraysandcosmicraysarehighlylethaltoDNAandother

vitalconstituents.

y commercialplantsusegammaradiationforsterilizingitemslikeplastics,syringes,swabs,catheters,animalfeeds,cardboards,oils,greases,fabrics,andmetalfoils.

y Highenergyelectronradiationasamethodofsterilizationisnotwidelyusedinmedicine.

Chemicals

y Alcohols:ethyl,isopropyl,trichlorobutanol

y Aldehydes:Formaldehyde,glutarldehyde

y Dyes

y a ogens

y Phenols

y Surfaceactiveagents

y Metallicsalts

y Gases:ethyleneoxide,formaldehyde,betapropiolactone.

in the workplace

in residential houses

in medical facilities

in manufacturing operations in which metalworking fluids are used

in animal-hair processing facilities

ProminentBioaerosolsCommonly found

n a ry ac es

in food processing plants

livestock farming and animal houses

in sites of sludge application

in recycling or composting plants

in sanitary landfills in sewage plants

Outdoor SourcesofBioaerosol Wind action on soil, agitation of open water, and raindrop impaction are

major sources of bioaerosols.

Farming of land.

Other farming activities, cattle, swi ne animal houses will generate

bioaerosols.

Wastewater/sewage treatment.

Food processing plants, particularly of dairy products can generate higher

levels of bioaerosols.


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Indoor SourcesofBioaerosol Many indoor areas are associated wit h bioaerosol problems.

In all food processing plants, hygiene requires that levels of airbornemicroorganisms are kept as low as possible.

Hospitals and health care facilities are not only so urces of a variety oforganisms, but r equire that patients are not exposed to any of them.

The presence of undesirable bioaerosols is often associated with sickbuilding syndrome, being one of a number of factors which contribute tobuilding related illness.

HVAC systems ventilation systems

BIOAEROSOLS&HEALTHEFFECTSy Sickbuildingsyndromespecificbuildingrelated

symptoms nonspec c u ngre ate nesses .

Buildingrelatedillnessy Infection(viral,legionellosis,tuberculosis)

y Syndromerelatedtoexposuretochemical/physicalagent(COpoisoning,dermatitisfromglassfibres)

y Immunologicallymediated(rhinitis,asthma,sinusitis)

y Inhalationfeverassociatedwithexposureto

biologicalagent

(humidifier

fever/Pontiac

fever)

Buildingrelatedsymptomy Nonspecificsymptoms(eye,nose,throat

irritation,headache,fatigue)cannot beassociated

thetimespentinthebuilding.


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Healtheffects contdy HypersensitivityDiseases:exposuretoantigens

whichstimulate

y Rhinitis&sinusitis:associatedwithconjunctivitis

s ma:c es g ness,w eez ng,coug

y Hypersensitivitypneumonitis:acute/chronic

y InhalationFever:Humidifierfeverflulikeillnessrelatedtoendotoxins/Legionnairesdisease&Pontiacfever.

y InfectionsThankyou

39047609 Fundamentals of Bioaerosol BJ

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