Open AccessRapid culture‐based detection of Legionella pneumophila using isothermal microcalorimetry with an improved evaluation method
Author(s) -
Fricke Christian,
Xu Juan,
Jiang FengLei,
Liu Yi,
Harms Hauke,
Maskow Thomas
Publication year - 2020
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.13563
Subject(s) - legionella pneumophila , isothermal microcalorimetry , isothermal process , legionella , gold standard (test) , contamination , reliability (semiconductor) , computer science , biological system , microbiology and biotechnology , chemistry , environmental science , biology , bacteria , mathematics , physics , thermodynamics , statistics , ecology , genetics , enthalpy , power (physics)
Summary The detection and quantification of Legionella pneumophila (responsible for legionnaire's disease) in water samples can be achieved by various methods. However, the culture‐based ISO 11731:2017, which is based on counts of colony‐forming units per ml (CFU·ml ‐1 ) is still the gold standard for quantification of Legionella species (spp.). As a powerful alternative, we propose real‐time monitoring of the growth of L . pneumophila using an isothermal microcalorimeter (IMC). Our results demonstrate that, depending on the initial concentration of L . pneumophila , detection times of 24–48 h can be reliably achieved. IMC may, therefore, be used as an early warning system for L. pneumophila contamination. By replacing only visual detection of growth by a thermal sensor, but otherwise maintaining the standardized protocol of the ISO 11731:2017, the new procedure could easily be incorporated into existing standards. The exact determination of the beginning of metabolic heat is often very difficult because at the beginning of the calorimetric signal the thermal stabilization and the metabolic heat development overlap. Here, we propose a new data evaluation based on the first derivation of the heat flow signal. The improved evaluation method can further reduce detection times and significantly increase the reliability of the IMC approach.