title: Rapid quantification method for Legionella pneumophila in surface water.
abstract: World-wide legionellosis outbreaks caused by evaporative cooling systems have shown that there is a need for rapid screening methods for Legionella pneumophila in water. Antibody-based methods for the quantification of L. pneumophila are rapid, non-laborious, and relatively cheap but not sensitive enough for establishment as a screening method for surface and drinking water. Therefore, preconcentration methods have to be applied in advance to reach the needed sensitivity. In a basic test, monolithic adsorption filtration (MAF) was used as primary preconcentration method that adsorbs L. pneumophila with high efficiency. Ten-liter water samples were concentrated in 10 min and further reduced to 1 mL by centrifugal ultrafiltration (CeUF). The quantification of L. pneumophila strains belonging to the monoclonal subtype Bellingham was performed via flow-based chemiluminescence sandwich microarray immunoassays (CL-SMIA) in 36 min. The whole analysis process takes 90 min. A polyclonal antibody (pAb) against L. pneumophila serogroup 1-12 and a monoclonal antibody (mAb) against L. pneumophila SG 1 strain Bellingham were immobilized on a microarray chip. Without preconcentration, the detection limit was 4.0 × 10(3) and 2.8 × 10(3) CFU/mL determined by pAb and mAb 10/6, respectively. For samples processed by MAF-CeUF prior to SMIA detection, the limit of detection (LOD) could be decreased to 8.7 CFU/mL and 0.39 CFU/mL, respectively. A recovery of 99.8 ± 15.9% was achieved for concentrations between 1-1000 CFU/mL. The established combined analytical method is sensitive for rapid screening of surface and drinking water to allow fast hygiene control of L. pneumophila.
authors.affiliation: Chair of Analytical Chemistry and Institute of Hydrochemistry, Technical University of Munich, Marchioninistraße 17, 81377, Munich, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Wunderlich
authors.affiliation: Chair of Analytical Chemistry and Institute of Hydrochemistry, Technical University of Munich, Marchioninistraße 17, 81377, Munich, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Torggler
authors.affiliation: Chair of Analytical Chemistry and Institute of Hydrochemistry, Technical University of Munich, Marchioninistraße 17, 81377, Munich, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Elsässer
authors.affiliation: Institute of Medical Microbiology and Hygiene, Institute of Virology, Medical Faculty "C. G. Carus", Technical University of Dresden, Fiedlerstraße 42, 01307, Dresden, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Lück
authors.affiliation: Chair of Analytical Chemistry and Institute of Hydrochemistry, Technical University of Munich, Marchioninistraße 17, 81377, Munich, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.affiliation: Chair of Analytical Chemistry and Institute of Hydrochemistry, Technical University of Munich, Marchioninistraße 17, 81377, Munich, Germany. Michael.Seidel@ch.tum.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Seidel
mesh_terms: D002138:Calibration; D005618:Fresh Water / Q000382:microbiology; D007118:Immunoassay / Q000379:methods; D016952:Legionella pneumophila / Q000302:isolation & purification*; D014462:Ultrafiltration; D014871:Water Microbiology
keywords: Legionella pneumophila; Microarray-based immunoassay; Monolith; Preconcentration of bacteria; Surface water