New procedure for rapid identification of microorganisms causing urinary tract infection from urine samples by mass spectrometry (MALDI-TOF)

a b s t r a c t Introduction: Matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrome- try is widely established as a technique in clinical microbiology laboratories for the identification of microorganisms. Using this technique, it is also possible to obtain the identification of microorganisms from untreated urine samples. Methods: In this study, a differential centrifugation protocol and a criterion for validation of the results in order to achieve microbial identification from untreated urine samples are proposed. Additionally, the sensitivity of the analytical procedure in monobacterial urine samples has been evaluated. Results: A 90% sensitivity (confidence interval of 81.96%-94.84%) was obtained in urine samples with bac- terial counts of ≥1 × 10