Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures

ABSTRACT A positive blood culture is a critical result that requires prompt identification of the causative agent. This article describes a simple method to identify microorganisms from positive blood culture broth within the time taken to perform a Gram stain (<20 min). The method is based on in...

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Autores principales: John D. Walsh, Jay M. Hyman, Larisa Borzhemskaya, Ann Bowen, Caroline McKellar, Michael Ullery, Erin Mathias, Christopher Ronsick, John Link, Mark Wilson, Bradford Clay, Ron Robinson, Thurman Thorpe, Alex van Belkum, W. Michael Dunne
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Publicado: American Society for Microbiology 2013
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spelling oai:doaj.org-article:c344f9f7412c48a78262d52fa3cb6e712021-11-15T15:42:31ZRapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures10.1128/mBio.00865-132150-7511https://doaj.org/article/c344f9f7412c48a78262d52fa3cb6e712013-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00865-13https://doaj.org/toc/2150-7511ABSTRACT A positive blood culture is a critical result that requires prompt identification of the causative agent. This article describes a simple method to identify microorganisms from positive blood culture broth within the time taken to perform a Gram stain (<20 min). The method is based on intrinsic fluorescence spectroscopy (IFS) of whole cells and required development of a selective lysis buffer, aqueous density cushion, optical microcentrifuge tube, and reference database. A total of 1,121 monomicrobial-positive broth samples from 751 strains were analyzed to build a database representing 37 of the most commonly encountered species in bloodstream infections or present as contaminants. A multistage algorithm correctly classified 99.6% of unknown samples to the Gram level, 99.3% to the family level, and 96.5% to the species level. There were no incorrect results given at the Gram or family classification levels, while 0.8% of results were discordant at the species level. In 8/9 incorrect species results, the misidentified isolate was assigned to a species of the same genus. This unique combination of selective lysis, density centrifugation, and IFS can rapidly identify the most common microbial species present in positive blood cultures. Faster identification of the etiologic agent may benefit the clinical management of sepsis. Further evaluation is now warranted to determine the performance of the method using clinical blood culture specimens. IMPORTANCE Physicians often require the identity of the infective agent in order to make life-saving adjustments to empirical therapy or to switch to less expensive and/or more targeted antimicrobials. However, standard identification procedures take up to 2 days after a blood culture is signaled positive, and even most rapid molecular techniques take several hours to provide a result. Other techniques are faster (e.g., matrix-assisted laser desorption ionization–time of flight [MALDI-TOF] mass spectrometry) but require time-consuming manual processing steps and expensive equipment. There remains a clear need for a simple, inexpensive method to rapidly identify microorganisms directly from positive blood cultures. The promising new method described in this research article can identify microorganisms in minutes by optical spectroscopy, thus permitting the lab to simultaneously report the presence of a positive blood culture and the organism’s identity.John D. WalshJay M. HymanLarisa BorzhemskayaAnn BowenCaroline McKellarMichael UlleryErin MathiasChristopher RonsickJohn LinkMark WilsonBradford ClayRon RobinsonThurman ThorpeAlex van BelkumW. Michael DunneAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 4, Iss 6 (2013)
institution DOAJ
collection DOAJ
language EN
topic Microbiology
QR1-502
spellingShingle Microbiology
QR1-502
John D. Walsh
Jay M. Hyman
Larisa Borzhemskaya
Ann Bowen
Caroline McKellar
Michael Ullery
Erin Mathias
Christopher Ronsick
John Link
Mark Wilson
Bradford Clay
Ron Robinson
Thurman Thorpe
Alex van Belkum
W. Michael Dunne
Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
description ABSTRACT A positive blood culture is a critical result that requires prompt identification of the causative agent. This article describes a simple method to identify microorganisms from positive blood culture broth within the time taken to perform a Gram stain (<20 min). The method is based on intrinsic fluorescence spectroscopy (IFS) of whole cells and required development of a selective lysis buffer, aqueous density cushion, optical microcentrifuge tube, and reference database. A total of 1,121 monomicrobial-positive broth samples from 751 strains were analyzed to build a database representing 37 of the most commonly encountered species in bloodstream infections or present as contaminants. A multistage algorithm correctly classified 99.6% of unknown samples to the Gram level, 99.3% to the family level, and 96.5% to the species level. There were no incorrect results given at the Gram or family classification levels, while 0.8% of results were discordant at the species level. In 8/9 incorrect species results, the misidentified isolate was assigned to a species of the same genus. This unique combination of selective lysis, density centrifugation, and IFS can rapidly identify the most common microbial species present in positive blood cultures. Faster identification of the etiologic agent may benefit the clinical management of sepsis. Further evaluation is now warranted to determine the performance of the method using clinical blood culture specimens. IMPORTANCE Physicians often require the identity of the infective agent in order to make life-saving adjustments to empirical therapy or to switch to less expensive and/or more targeted antimicrobials. However, standard identification procedures take up to 2 days after a blood culture is signaled positive, and even most rapid molecular techniques take several hours to provide a result. Other techniques are faster (e.g., matrix-assisted laser desorption ionization–time of flight [MALDI-TOF] mass spectrometry) but require time-consuming manual processing steps and expensive equipment. There remains a clear need for a simple, inexpensive method to rapidly identify microorganisms directly from positive blood cultures. The promising new method described in this research article can identify microorganisms in minutes by optical spectroscopy, thus permitting the lab to simultaneously report the presence of a positive blood culture and the organism’s identity.
format article
author John D. Walsh
Jay M. Hyman
Larisa Borzhemskaya
Ann Bowen
Caroline McKellar
Michael Ullery
Erin Mathias
Christopher Ronsick
John Link
Mark Wilson
Bradford Clay
Ron Robinson
Thurman Thorpe
Alex van Belkum
W. Michael Dunne
author_facet John D. Walsh
Jay M. Hyman
Larisa Borzhemskaya
Ann Bowen
Caroline McKellar
Michael Ullery
Erin Mathias
Christopher Ronsick
John Link
Mark Wilson
Bradford Clay
Ron Robinson
Thurman Thorpe
Alex van Belkum
W. Michael Dunne
author_sort John D. Walsh
title Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
title_short Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
title_full Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
title_fullStr Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
title_full_unstemmed Rapid Intrinsic Fluorescence Method for Direct Identification of Pathogens in Blood Cultures
title_sort rapid intrinsic fluorescence method for direct identification of pathogens in blood cultures
publisher American Society for Microbiology
publishDate 2013
url https://doaj.org/article/c344f9f7412c48a78262d52fa3cb6e71
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