Free-living amoebae (FLA) co-occurring with legionellae in industrial waters

Ute Scheikl, Regina Sommer, Alexander Kirschner, Alexandra Rameder, Barbara Schrammel, Irene Zweimüller, Wolfgang Wesner, Manfred Hinker, Julia Walochnik*

*Corresponding author for this work

Research output: Journal article (peer-reviewed)Journal article

48 Citations (Scopus)


Legionella pneumophila is known as the causative agent of Legionnaires' disease and free-living amoebae (FLA) can serve as vehicles for legionellae. The aim of this study was to screen industrial waters for the occurrence of FLA and their co-occurrence with legionellae. A total of 201 water samples, including 129 cooling waters and 72 process waters, and 30 cooling lubricants were included in the study. Treated waters were screened periodically, pre and post treatment. Altogether, 72.6% of the water samples were positive for FLA, acanthamoebae being most prevalent (in 23.9% of the samples) followed by Vermamoeba vermiformis (19.4%). Only one cooling lubricant was positive (Acanthamoeba genotype T4). Legionella spp. were detected in 34.8% of the water samples and in 15% in high concentrations (>1000. CFU/100. ml). Altogether, 81.4% of the Legionella-positive samples were positive for FLA by standard methods. By applying a highly sensitive nested PCR to a representative set of random samples it was revealed that Legionella spp. always co-occurred with Acanthamoeba spp. Although the addition of disinfectants did influence amoebal density and diversity, treated waters showed no difference concerning FLA in the interphases of disinfection. It appears that FLA can re-colonize treated waters within a short period of time.

Original languageEnglish
Pages (from-to)422-429
Number of pages8
JournalEuropean Journal of Protistology
Issue number4
Publication statusPublished - Aug 2014
Externally publishedYes


  • Acanthamoeba
  • Free-living amoebae
  • Industrial water
  • Legionella
  • PCR

ASJC Scopus subject areas

  • Microbiology


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