Development of Untargeted Metabolomics-based Detection Method for Naegleria fowleri: A Year-Long Monitoring of the Microbial Ecology in an Operational Drinking Water Distribution System

Naegleria fowleri is known to be the causative agent of highly aggressive (> 95 % mortality rate) primary amoebic meningoencephalitis (PAM). N. fowleri can colonize drinking water distribution systems (DWDSs) which place additional pressures on water distribution authorities and public health officials. Chlorination and chloramination are widely adopted to combat N. fowleri in DWDSs but this approach is susceptible to failure in certain situations which makes effective N. fowleri surveillance necessary to protect the public from infection. Based on our previous efforts to develop a rapid N. fowleri detection method focusing on the lab-cultured and field-collected samples, this manuscript presents our recent progress investigating an operational DWDS field site seasonally colonized by N. fowleri on a monthly basis over the course of a year using untargeted metabolomics of the entire microbial ecology. A panel of significant features exhibiting changes between N. fowleri positive and negative samples were found and further correlated with the findings from the previous studies. The chemical identities for a subset of the common significant features were confirmed. A new, seasonal prediction model was built based on the common significant features and its performance was compared with our previous efforts. This study illustrates the further development of a rapid N. fowleri detection approach from a longitudinal perspective.