Microbiological quality inFinnish public swimming pools andwhirlpools withspecial reference tofree living amoebae: arisk factor for contactlens wearers?

To assessthepossible riskofmicrobial keratitis associated withswimmingor bathing inpublic pools,themicrobiological quality aswellasthepresence of freeliving amoebaein 16halogenated swimming pools andwhirlpools, located in Helsinki, Finland, wasdetermined. Five additional whirlpools situated in the ferries cruising fromFinland toSweden wereincluded inthestudy. Otherparametersinvestigated werethetotal bacterialcount,identification ofPseudomonas aeruginosa andStaphylococcus aureus, measurementoffreeresidual andcombinedchlorine, potassium permanganate index, urine, pH,andturbidity. Amoebae weredetected in41% ofthepoolwater samples studied. Sevenof11whirlpools andfourof10swimmingpools wereshown tocontain amoebae.An Acanthamoeba species wasisolated fromonly oneoutdoor swimmingpool;the otheramoebae belongedto the generaVexfilifera, Flabellula, Hartmannella, andRugipes. Althoughnota single verified caseof Acanthamoeba keratitis hasbeenfoundin Finland, thefindings showthatthereisa theoretical riskofamoebicandbacterial keratitis associated withswimmingor bathing inproperly cleaned public pools. Consequently, we do not recommend swimming orbathing withcontact lenses. (BrJOphthalmol 1995; 79:178-181)