Competition between Naegleria fowleri and Free Living Amoeba Colonizing Laboratory Scale and Operational Drinking Water Distribution Systems

Free living amoebae (FLA), including pathogenic Naegleria fowleri, can colonise and grow within pipe wall biofilms of drinking water distribution systems (DWDSs). Studies on the interactions between various FLA species in biofilms are limited. Understanding the interaction between FLA and the broader biofilm ecology could help better predict DWDS susceptibility to N. fowleri colonisation. The aim of this study was to determine if N. fowleri and other FLAs (Naegleria, Vermamoeba, Willaertia and Vahlkampfia spp.) co-colonise DWDS biofilm. FLAs commonly isolated from DWDSs (N. fowleri, V. vermiformis and N. lovaniensis) were introduced into laboratory-scale biomonitors to determine the impact of these amoebae on N. fowleri’s presence and viability. Over 18 months, a single viable amoebae (N. fowleri, N. lovaniensis, or V. vermiformis) was detected in each biofilm sample, with the exception of N. lovaniensis and N. fowleri, which briefly co-colonised biofilm following their co-inoculation. The analysis of bio...