Subculturing and Gram staining of blood cultures flagged negative by the BACTEC™ FX system: Optimizing the workflow for detection of Cryptococcus neoformans in clinical specimens

ObjectiveTo investigate whether an incubation time of 5 days (Aerobic/F, Anaerobic/F) and 14 days (Myco/F) blood culture bottles is sufficient to prevent false-negative results.MethodsWe evaluated 1,244 blood bottles (344 patients) defined as negative by the BACTEC™ FX system. We also reviewed publi...

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Bibliographic Details
Main Authors: Lingli Liu, Lijun Du, Shuquan He, Tianshu Sun, Fanrong Kong, Yali Liu, Yingchun Xu
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-03-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2023.1113817/full
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Summary:ObjectiveTo investigate whether an incubation time of 5 days (Aerobic/F, Anaerobic/F) and 14 days (Myco/F) blood culture bottles is sufficient to prevent false-negative results.MethodsWe evaluated 1,244 blood bottles (344 patients) defined as negative by the BACTEC™ FX system. We also reviewed published cases and our own cases of bloodstream infection caused by Cryptococcus neoformans and simulated different scenarios, including different inoculation concentrations, bottle types, and clinical isolates.ResultsTwo bottles (0.16%) were found to contain C. neoformans when subcultured and Gram stained. A 5-day protocol with Aerobic/F bottles was insufficient for the growth of C. neoformans in some cases, and C. neoformans grew better in Myco/F bottles than in Aerobic/F bottles.ConclusionSubculturing and Gram staining after a 5-day protocol were important for the detection of C. neoformans, and Myco/F bottles should be collected for the blood culture of C. neoformans.
ISSN:1664-302X