{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T06:39:36Z","timestamp":1763707176978,"version":"3.45.0"},"reference-count":17,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T00:00:00Z","timestamp":1763683200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:p>\n                    Bloodstream infections caused by antimicrobial-resistant Gram-negative bacilli are often difficult to treat. Here, we investigated the performance of a workflow for direct detection of Gram-negative bacilli and extended-spectrum \u03b2-lactamase (ESBL) producers in positive blood culture (PBC) specimens using matrix-assisted laser desorption ionization\u2013time-of-flight mass spectrometry (MALDI-TOF MS). Samples were prepared from spiked and clinical PBC specimens using a sample preparation kit, and bacterial identification and cephalosporinase activity assays were performed using MALDI-TOF MS. The results were compared with those obtained using the conventional method, which was performed for colonies as routine microbiological testing. Of the 34 spiked PBC specimens prepared using\n                    <jats:italic>Escherichia coli<\/jats:italic>\n                    and\n                    <jats:italic>Klebsiella pneumoniae<\/jats:italic>\n                    isolates, all 27 ESBL producers tested positive and seven non-producers tested negative for cephalosporinase activity. Of the 111 clinical PBC specimens analyzed, 99 (89.2%) showed concordance with the conventional method results, with scores \u2265 2.00. Among the 54 Enterobacterales, consisting of\n                    <jats:italic>E. coli<\/jats:italic>\n                    ,\n                    <jats:italic>K. pneumoniae<\/jats:italic>\n                    ,\n                    <jats:italic>Klebsiella oxytoca<\/jats:italic>\n                    , and\n                    <jats:italic>Proteus mirabilis<\/jats:italic>\n                    isolates identified in the directly prepared samples, 14 were ESBL producers in the colonies. Of the 14 ESBL producers, 11 (78.6%) were correctly identified as cephalosporinase producers in the directly prepared samples using MALDI-TOF MS. The time required for direct identification (8.4\u00a0h) was significantly shorter than that required for conventional identification (15.0\u00a0h). Moreover, the time required for cephalosporinase activity detection in the directly prepared samples (9.2\u00a0h) was significantly shorter than that required for phenotypic ESBL detection in colonies (32.3\u00a0h). This study demonstrates the performance of the workflow for direct detection of Gram-negative bacilli and cephalosporinase activity in ESBL producers from PBC specimens using MALDI-TOF MS.\n                  <\/jats:p>","DOI":"10.3389\/fcimb.2025.1701423","type":"journal-article","created":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T06:29:47Z","timestamp":1763706587000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Direct detection of Gram-negative bacilli and extended-spectrum \u03b2-lactamase producers in positive blood culture specimens using MALDI-TOF MS"],"prefix":"10.3389","volume":"15","author":[{"given":"Kosuke","family":"Kosai","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yasuhide","family":"Kawamoto","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fujiko","family":"Mitsumoto-Kaseida","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Norihito","family":"Kaku","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiroo","family":"Hasegawa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takahiro","family":"Takazono","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Koichi","family":"Izumikawa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiroshi","family":"Mukae","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katsunori","family":"Yanagihara","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2025,11,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"322","DOI":"10.3390\/microorganisms12020322","article-title":"MALDI-TOF MS: a reliable tool in the real life of the clinical microbiology laboratory","volume":"12","author":"Calderaro","year":"2024","journal-title":"Microorganisms."},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1016\/j.eclinm.2022.101781","article-title":"Antimicrobial resistance and mortality following E. coli bacteremia","volume":"56","author":"Daneman","year":"2023","journal-title":"EClinicalMedicine."},{"key":"B3","doi-asserted-by":"publisher","first-page":"380","DOI":"10.1056\/NEJMra041359","article-title":"The new \u03b2-lactamases","volume":"352","author":"Jacoby","year":"2005","journal-title":"N. Engl. J. Med."},{"key":"B4","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1016\/j.diagmicrobio.2018.06.018","article-title":"Performance evaluation of the MALDI Biotyper Selective Testing of Antibiotic Resistance-\u03b2-Lactamase (MBT STAR-BL) assay for the detection of IMP metallo-\u03b2-lactamase activity in Enterobacteriaceae","volume":"92","author":"Kawamoto","year":"2018","journal-title":"Diagn. Microbiol. Infect. Dis."},{"key":"B5","doi-asserted-by":"publisher","first-page":"154","DOI":"10.1016\/j.mimet.2019.03.019","article-title":"Detection of extended-spectrum \u03b2-lactamase (ESBL)-producing Enterobacteriaceae using the MALDI Biotyper Selective Testing of Antibiotic Resistance-\u03b2-Lactamase (MBT STAR-BL) assay","volume":"160","author":"Kawamoto","year":"2019","journal-title":"J. Microbiol. 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Microbiol."},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.3389\/fcimb.2023.1157010","article-title":"Klebsiella pneumoniae bacteremia mortality: a systematic review and meta-analysis","volume":"13","author":"Li","year":"2023","journal-title":"Front. Cell. Infect. Microbiol."},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1155\/2015\/827416","article-title":"Rapid identification of pathogens in positive blood culture of patients with sepsis: review and meta-analysis of the performance of the sepsityper kit","volume":"2015","author":"Morgenthaler","year":"2015","journal-title":"Int. J. Microbiol."},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1016\/j.mimet.2021.106166","article-title":"Evaluation of MBT STAR-Cepha and MBT STAR-Carba kits for the detection of extended-spectrum \u03b2-lactamases and carbapenemase producing microorganisms using matrix-assisted laser desorption\/ionization time-of-flight mass spectrometry","volume":"183","author":"Ota","year":"2021","journal-title":"J. Microbiol. Methods"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1016\/j.mimet.2023.106756","article-title":"Utility of the MBT STAR-Cepha kit in detecting extended-spectrum \u03b2-lactamase producers in clinical urine samples and positive blood cultures using matrix-assisted laser desorption\/ionization time-of-flight mass spectrometry","volume":"211","author":"Ota","year":"2023","journal-title":"J. Microbiol. 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Chemother."},{"key":"B15","doi-asserted-by":"publisher","first-page":"48","DOI":"10.1016\/j.ymeth.2016.01.008","article-title":"MBT-ASTRA: A suitable tool for fast antibiotic susceptibility testing","volume":"104","author":"Sparbier","year":"2016","journal-title":"Methods."},{"key":"B16","doi-asserted-by":"publisher","first-page":"1987","DOI":"10.1128\/AAC.01509-06","article-title":"Predictors of mortality in patients with bloodstream infections caused by extended-spectrum-\u03b2-lactamase-producing Enterobacteriaceae: importance of inadequate initial antimicrobial treatment","volume":"51","author":"Tumbarello","year":"2007","journal-title":"Antimicrob. Agents. 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Dis."}],"container-title":["Frontiers in Cellular and Infection Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcimb.2025.1701423\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T06:29:48Z","timestamp":1763706588000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcimb.2025.1701423\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,21]]},"references-count":17,"alternative-id":["10.3389\/fcimb.2025.1701423"],"URL":"https:\/\/doi.org\/10.3389\/fcimb.2025.1701423","relation":{},"ISSN":["2235-2988"],"issn-type":[{"value":"2235-2988","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,21]]},"article-number":"1701423"}}