Comparative evaluation of Duopath Legionella lateral flow assay against the conventional culture method using Legionella pneumophila and Legionella anisa strains.
Duopath Legionella is a new immunochromatographic assay for the identification of Legionella pneumophila and Legionella spp. As excellent specificity has been previously reported for this kit, we attempted an evaluation of its sensitivity using L. pneumophila serogroup 1 and Legionella anisa strains. Bacterial suspensions of L. pneumophila at concentrations of 1.2 x 10(8) cfu/ml and 1.2 x 10(7) cfu/ml were detected, but those below 1.2 x 10(6) cfu/ml were not recognized by the Duopath kit. After centrifugation and the sediment resuspension, a 2.8 x 10(7) cfu/ml concentration of bacterial suspension showed a positive result, but negative results were obtained below 2.8 x 10(6) cfu/ml. Also, bacterial suspension with concentrations of 3.2 x 10(9) cfu/ml and 1.4 x 10(9) cfu/ml after centrifugation of L.anisa were detected, but those below 3.2 x 10(8) cfu/ml and 1.4 x 10(8) cfu/ml after centrifugation were not recognized by the Duopath kit. Meanwhile, this kit was less sensitive to the L. pneumophila serogroup 1 suspension, and was more sensitive to the L. pneumophila serogroup 2 and L.anisa than the Binax NOW immunochromatographic kit. It was realized that the sensitivity of this kit is too low for determining the presence of Legionella in water samples. Although this kit may have excellent specificity, it has low sensitivity.
Koide
Michio
M
Department of Medicine and Therapeutics, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan. koide-mi@med.u-ryukyu.ac.jp
Haranaga
Shusaku
S
Higa
Futoshi
F
Tateyama
Masao
M
Yamane
Nobuhisa
N
Fujita
Jiro
J
D001431:Bacteriological Techniques / Q000379:methods; D002845:Chromatography / Q000379:methods; D007158:Immunologic Techniques; D007875:Legionella / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification; D016952:Legionella pneumophila / Q000145:classification / Q000276:immunology / Q000302:isolation & purification; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014871:Water Microbiology
D011933:Reagent Kits, Diagnostic