%A Zhou,Menglan %A Yang,Qiwen %A Kudinha,Timothy %A Sun,Liying %A Zhang,Rui %A Liu,Chang %A Yu,Shuying %A Xiao,Meng %A Kong,Fanrong %A Zhao,Yupei %A Xu,Ying-Chun %D 2017 %J Frontiers in Microbiology %C %F %G English %K Blood culture,Bloodstream infection,Cost-Effectively,Direct identification,MALDI-TOF mass-spectrometry %Q %R 10.3389/fmicb.2017.01824 %W %L %M %P %7 %8 2017-September-28 %9 Original Research %+ Qiwen Yang,Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences,China,yangqiwen81@vip.163.com %+ Qiwen Yang,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases,China,yangqiwen81@vip.163.com %+ Ying-Chun Xu,Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences,China,xycpumch@139.com %+ Ying-Chun Xu,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases,China,xycpumch@139.com %# %! Improved direct detection of organisms in blood cultures using an in-house MALDI-TOF protocol. %* %< %T An Improved In-house MALDI-TOF MS Protocol for Direct Cost-Effective Identification of Pathogens from Blood Cultures %U https://www.frontiersin.org/articles/10.3389/fmicb.2017.01824 %V 8 %0 JOURNAL ARTICLE %@ 1664-302X %X Background: Bloodstream infection is a major cause of morbidity and mortality in hospitalized patients worldwide. Delays in the identification of microorganisms often leads to a poor prognosis. The application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) directly to blood culture (BC) broth can potentially identify bloodstream infections earlier, and facilitate timely management.Methods: We developed an “in-house” (IH) protocol for direct MALDI-TOF MS based identification of organisms in positive BCs. The IH protocol was initially evaluated and improved with spiked BC samples, and its performance was compared with the commercial Sepsityper™ kit using both traditional and modified cut-off values. We then studied in parallel the performance of the IH protocol and the colony MS identifications in positive clinical BC samples using only modified cut-off values. All discrepancies were investigated by “gold standard” of gene sequencing.Results: In 54 spiked BC samples, the IH method showed comparable results with Sepsityper™ after applying modified cut-off values. Specifically, accurate species and genus level identification was achieved in 88.7 and 3.9% of all the clinical monomicrobial BCs (284/301, 94.4%), respectively. The IH protocol exhibited superior performance for Gram negative bacteria than for Gram positive bacteria (92.8 vs. 82.4%). For anaerobes and yeasts, accurate species identification was achieved in 80.0 and 90.0% of the cases, respectively. For polymicrobial cultures (17/301, 5.6%), MALDI-TOF MS correctly identified a single species present in all the polymicrobial BCs under the Standard mode, while using the MIXED method, two species were correctly identified in 52.9% of the samples. Comparisons based on BC bottle type, showed that the BACTEC™ Lytic/10 Anaerobic/F culture vials performed the best.Conclusion: Our study provides a novel and effective sample preparation method for MALDI-TOF MS direct identification of pathogens from positive BC vials, with a lower cost ($1.5 vs. $ 7) albeit a slightly more laborious extracting process (an extra 15 min) compared with Sepsityper™ kit.