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Acanthamoeba and other free-living amoebae in bat guano, an extreme habitat


Several representatives of the so-called free-living amoebae (FLA) are of medical relevance, not only as facultative pathogens but also as vehicles for pathogenic bacteria. Some FLA can survive and even grow under extreme environmental conditions. Bat guano is an exceptional habitat, the conditions becoming gradually more extreme with aging. In the current study, samples of bat guano of different ages from five caves in Slovenia were screened for the presence of FLA. FLA were isolated from almost all guano samples, including guano with a pH of 3.5. Only the two samples that had been drawn from >20-year-old guano were negative for FLA. Generally, FLA diversity correlated to high concentrations of cultivable bacteria (∼108 CFU/g) and fungi (∼105 CFU/g). Interestingly, the absence of FLA in seasoned guanos was mirrored by the presence of dictyostelid slime moulds. The isolated amoebae were identified as belonging to the genera Acanthamoeba, Copromyxa, Naegleria, Sappinia, Tetramitus, Thecamoeba, Vahlkampfia, Vannella and Vermamoeba. To the best of our knowledge, this is the first study on the diversity of FLA in guano.

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This study was supported by the programme Karst Research P6-0119, by the Austrian agency for International Cooperation (OeAD, Sl 24/2011), by the Austrian Science Fund (FWF, P24535) and by the Medical University of Vienna. The authors gratefully acknowledge Primož Presetnik, Drago Jeseničnik and Stane Cencič for providing valuable data on bats, Andreea Oarga, Janez Margon and Borut Peric for field work support, Iveta Haefeli and Jacek Pietrzak for laboratory assistance and David Lowe for language editing.

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Correspondence to Julia Walochnik.

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Mulec, J., Dietersdorfer, E., Üstüntürk-Onan, M. et al. Acanthamoeba and other free-living amoebae in bat guano, an extreme habitat. Parasitol Res 115, 1375–1383 (2016).

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  • Acidophilic
  • Amoebae
  • Bat faeces
  • Caves
  • pH