ProMoss™–Legionella–Amoeba
andLegionnaires’Disease
FEBRUARY17,2017BYDAVIDR.KNIGHTON,MD,CO-FOUNDER,PRESIDENTANDCHIEF
EXECUTIVEOFFICER
TheinterrelationshipbetweenLegionellabacteria,amoeba,organic
contaminationandwaterincoolingtowersandfountainscanproduce
aseverepneumoniacalledlegionnaires’disease.Inthissummary,we
willreviewthelifecycleofLegionellabacteria,reviewtheeffectsof
ProMoss™onorganiccontamination,anddiscusstheresultsof
LegionellatestingoncoolingtowerstreatedwithProMoss™inthestate
ofNewYork.
TheLegionellaLifecycle
Asshownintheaccompanyingdiagramtakenfromthis
article,Legionellabacteria,alongwithamoeba,liveintheorganic
contaminationonthesurfacesofwatersystems.Itisinterestingto
notethatLegionelladonotgrowlikeotherbacteria.Legionellacanonly
growwhentheyareinsideanothercell.Amoebaaresinglecell
organismsthatusuallyeatbacteriaandorganiccontaminationastheir
foodsource.WhenamoebaeatLegionella,thebacteriabecome
encapsulatednormally,butthesecapsulesnevercomeincontactwith
theenzymesthatusuallydestroythemsotheycanbecomefoodforthe
amoeba.TheLegionellacontinuetogrowinsidetheamoebaandare
eitherreleasedfromthediseasedamoebaintothewateroracyst
containingtheLegionellabacteriaisreleased.Inthisform,thebacteria
canbeaerosolizedandinhaledintoahumanhost.
Inthehuman,thecyclehappensagain,butthistimeinsteadofthe
amoebabeingtheinfectedcellitisalungimmunecellthattriestoeat
theLegionella.Butjustlikeintheamoeba,thebacterialiveandthrive
insidethecysts.Asthebacteriadivideandinfectmoreandmore
immunecells,thebacteriaspreadandcausepneumoniathatisvery
difficulttotreat.
ProMoss™andLegionnairesDisease
WeknowthatProMoss™inhibitstheformationandremovesorganic
contamination.Withoutorganiccontamination,amoebacan’teatand
don’tsurvive.Withouttheamoeba,theLegionellabacteriacan’t
survive.OneofthereasonsthatcontrollingLegionellawithchemicalsis
difficultisbecausebiocidesareabsorbedintoorganiccontamination,
andtheusuallevelofbiocideusedincoolingtowersistotally
ineffectiveagainstamoeba.Tokillamoebarequireshighlevelsof
biocideforlongperiodsoftime.Twoofthemosteffectivebiocides
againstamoebaareozoneandhydrogenperoxide.
ExperiencewithLegionellaTestinginNewYorkState
MikeBromley,fromWaterWiseofAmerica,Inc.,aCWSdealerinNew
York,hasover25coolingtowersonProMoss™usinghydrogenperoxide
asthebiocide.InthestateofNewYork,itisrequiredtoobtain
Legionellacolonycountsforcoolingtowerseverythreemonths.Ifthe
levelsaregreaterthan20colonyformingunitspermL(CFU/mL),the
towerneedstobedisinfectedandretested.Iftherearegreaterthan
1000CFU/mLthetowerneedstobedecontaminatedandretested.Ifit
isgreaterthan1000CFU/mLasecondtime,ithastobedrained,
decontaminated,refilledandretesteduntiltheLegionellalevelislower
than20CFU/mL.TherehavebeentwocoolingtowersusingProMoss™
thathavetestedpositiveforgreaterthan20CFU/mL.Theywereboth
disinfectedandretestedwithnoLegionellapresentatthenexttestor
thereafter.NoneoftheothertowersonProMoss™havetestedpositive
forLegionella.
Legionnaires’DiseasePrevention
TheuseofProMoss™alongwithanapprovedbiocideisshowntobe
veryeffectiveinmaintainingcoolingtowersfreefromLegionella
infestation.ThecombinationofProMoss™withhydrogenperoxide
generationprovidesatotallychemicalfreesystem.