AIMS: To evaluate the effect of temperature on two amoeba strains of the genera Acanthamoeba and two amoeba strains of the genera Hartmannella separately treated depending on their life stage, trophozoite or cyst, when cells are directly exposed under controlled conditions. METHODS AND RESULTS: For thermal treatments, three temperatures were selected 50, 60 and 70°C, and a microcosm was designed using dialysis bags. The inactivation of each strain was determined using a method based on the most probable number quantification on agar plates. The results showed that for all amoeba strains, thermal treatment was more effective against trophozoites compared with cyst stages. The inactivation patterns showed statistical differences between the two genera analysed at temperatures above 50°C. The effectiveness of the thermal treatments at 60 and 70°C was higher for both life stages of Hartmannella vermiformis strains compared with Acanthamoeba strains, being the most resistant Acanthamoeba cysts. CONCLUSIONS: Free-living amoebae have been isolated in a wide range of environments worldwide due to their capacity to survive under harsh conditions. This capacity is mainly based on the formation of resistant forms, such as double-walled cysts, which confers a high level of resistance as shown here for thermal treatments. SIGNIFICANCE AND IMPACT OF STUDY: Free-living amoebae survival can promote a rapid recolonization of drinking water systems and is a likely source of emerging opportunistic pathogens such as Legionella. Because of that a better understanding of the factors that affect micro-organism inactivation in water systems would allow more efficient application of disinfection treatments.
AIMS: To evaluate the effect of temperature on two amoeba strains of the genera Acanthamoeba and two amoeba strains of the genera Hartmannella separately treated depending on their life stage, trophozoite or cyst, when cells are directly exposed under controlled conditions. METHODS AND RESULTS: For thermal treatments, three temperatures were selected 50, 60 and 70°C, and a microcosm was designed using dialysis bags. The inactivation of each strain was determined using a method based on the most probable number quantification on agar plates. The results showed that for all amoeba strains, thermal treatment was more effective against trophozoites compared with cyst stages. The inactivation patterns showed statistical differences between the two genera analysed at temperatures above 50°C. The effectiveness of the thermal treatments at 60 and 70°C was higher for both life stages of Hartmannella vermiformis strains compared with Acanthamoeba strains, being the most resistant Acanthamoeba cysts. CONCLUSIONS: Free-living amoebae have been isolated in a wide range of environments worldwide due to their capacity to survive under harsh conditions. This capacity is mainly based on the formation of resistant forms, such as double-walled cysts, which confers a high level of resistance as shown here for thermal treatments. SIGNIFICANCE AND IMPACT OF STUDY: Free-living amoebae survival can promote a rapid recolonization of drinking water systems and is a likely source of emerging opportunistic pathogens such as Legionella. Because of that a better understanding of the factors that affect micro-organism inactivation in water systems would allow more efficient application of disinfection treatments.
Authors: Oriol Canals; Alejandra Serrano-Suárez; Humbert Salvadó; Javier Méndez; Sílvia Cervero-Aragó; Vicenç Ruiz de Porras; Jordi Dellundé; Rosa Araujo Journal: Environ Sci Pollut Res Int Date: 2014-11-21 Impact factor: 4.223
Authors: Sílvia Cervero-Aragó; Barbara Schrammel; Elisabeth Dietersdorfer; Regina Sommer; Christian Lück; Julia Walochnik; Alexander Kirschner Journal: Water Res Date: 2019-04-09 Impact factor: 11.236
Authors: Sílvia Cervero-Aragó; Sarah Rodríguez-Martínez; Antoni Puertas-Bennasar; Rosa M Araujo Journal: PLoS One Date: 2015-08-04 Impact factor: 3.240
Authors: Elisabeth Dietersdorfer; Sílvia Cervero-Aragó; Regina Sommer; Alexander K Kirschner; Julia Walochnik Journal: BMC Microbiol Date: 2016-04-26 Impact factor: 3.605