Abstract (eng)
Due to recent cases of legionellosis in European paper factories, an interdisciplinary project for an investigation of process water has been initiated. The aim of the study was to investigate the occurrence of Acanthamoeba, Hartmannella and Naegleria in water samples from Austrian paper factories. Naegleria fowleri is known as the causative agent of primary amoebic meningoencephalitis. Acanthamoeba species can cause infections in immunocompromised hosts (granulomatous amoebic encephalitis) as well as in immunocompetent humans (Acanthamoeba-keratitis). Furthermore, free-living amoebae (FLA), particularly acanthamoebae and hartmannellae, can serve as vectors and reservoir for Legionella pneumophila, the causative agent of Legionnaires´ disease.
To ensure a reliable detection, all samples were investigated by culture and molecular biological techniques in parallel. For this reason genus-specific PCR protocols were established. Additionally, employing sequence analysis Acanthamoeba genotypes were determined.
A total of 28 water samples from 16 factories were examined, with 27 samples being positive for FLA. Acanthamoeba species were most prevalent with 89%, followed by 32% of diverse FLA, such as echinamoebae and vahlkampfiae. Hartmannella was observed in 21% of the samples and Naegleria sp. was only detected once. 39% of the samples were positive for several genera of amoebae. In 18% (five of 28) of the samples Legionella spp. were present and co-occurred with Acanthamoeba. Hartmannella and Naegleria were present in one of five Legionella-positive samples, respectively.
These results show that FLA, particularly Acanthamoeba, are common in process waters and occur syntopically with Legionella spp. These findings confirm the role of FLA for the distribution of legionellae.