Combination of Coral UTI ScreenTM system,gram-stain and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for diagnosis of urinary tract infections directly from urine samples |
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Authors: | Julia Guzmán-Puche Manuel Causse Rocío Tejero-García Fernando Carlos Rodríguez-López Manuel Casal-Román |
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Institution: | 1. UGC Microbiology, Reina Sofía University Hospital, Córdoba, Spain;2. Maimónides Institute for Research in Biomedicine of Córdoba (IMIBIC), Universidad de Córdoba, Córdoba, Spain;3. Spanish Network for Infectious Disease Research (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain |
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Abstract: | This study proposes an algorithm for microbiological diagnosis of urinary tract infections based on screening by luminometry and Gram-stain, followed by identification by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Positive urine samples detected with the luminometry screening Coral UTI ScreenTM system underwent Gram staining and identification of the causative organism was performed by MALDI-TOF Microflex LT mass spectrometer (Bruker Daltonics, Germany). Subsequently, the results were compared with those of conventional culture identification using WIDER MIC/id system (Francisco Soria Melguizo SA, Spain). Considering the conventional approach as the gold standard, the proposed algorithm presented both a high specificity (98.1%) and a positive likelihood ratio of 37.42. The implementation of this algorithm would allow diagnosis of urinary tract infection in less than an hour in 92.4% of positive samples. This combination of techniques would be useful particularly for patients with severe UTI, pyelonephritis or urinary sepsis. |
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Keywords: | MALDI-TOF Luminometry Rapid diagnostic Gram stain Urinary tract infection Coral UTI ScreenTM system |
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