Survey of Naegleria and its resisting bacteria-Legionella in hot spring water of Taiwan using molecular method

Naegleria is a free-living amoebae existing in soil and aquatic environments. Within the genus Naegleria, N. fowleri is most recognized as potential human pathogen causing primary amoebic meningoencephalitis (PAM). Furthermore, the Naegleria spp. can serve as vehicles for facultative pathogens, such as Legionella. In this study, we identified Naegleria and Legionella based on the PCR amplification with a genus-specific primer pair and investigated the distribution of Naegleria and Legionella at five spring recreation areas in Taiwan. In this study of hot spring and other water sources in Taiwan, five Naegleria spp. were detected in 15 (14.2%) of the water samples. The most frequently detected was N. lovaniensis (n = 6), followed by N. australiensis (n = 5), and then N. clarki (n = 2). N. americana and N. pagei were detected once, respectively. The pathogenic species N. fowleri was not detected; however, N. australiensis considered to be a potential pathogen species in humans was found. Legionella spp., an endosymbiont of Naegleria, was detected in 19 (17.9%) of the water samples in this study. Overall, 5.7% of the water samples contained both Naegleria and Legionella. The Legionella spp. identified were L. pneumophila and L. erythra. Results of this survey confirm the existence of Naegleria and Legionella in Taiwan spring recreation areas. It should be considered a potential threat for health associated with human activities in spring recreation areas of Taiwan.