Optimal turnaround time for direct identification of microorganisms by mass spectrometry in blood culture

Randazzo, Adrien; Simón, Marc; Goffinet, P.; Classen, Jean-François; Hougardy, Nicolas; Pierre, P.; Kinzinger, Philippe; Mauel, Etienne; Goffinet, Jean-Sebastien

doi:10.1016/j.mimet.2016.08.019

Cited by 14 publications

(7 citation statements)

References 11 publications

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“…This study showed that next to blood and urine samples 22–24 , rapid identification of bacterial pathogens by MALDI-TOF MS, skipping the cultivation step on agar, is possible for BALf samples. Taking all samples into account, 73% was correctly identified after 6 hours of incubation, which would be a clinically desirable turnaround time for treatment initiation, since this could result in identification on the same day the sample was inoculated.…”

Section: Discussionmentioning

confidence: 91%

Rapid identification of respiratory bacterial pathogens from bronchoalveolar lavage fluid in cattle by MALDI-TOF MS

Driessche

Bokma

Deprez

et al. 2019

Sci Rep

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Respiratory tract infections are a major health problem and indication for antimicrobial use in cattle and in humans. Currently, most antimicrobial treatments are initiated without microbiological results, holding the risk of inappropriate first intention treatment. The main reason for this empirical treatment is the long turnaround time between sampling and availability of identification and susceptibility results. Therefore the objective of the present study was to develop a rapid identification procedure for pathogenic respiratory bacteria in bronchoalveolar lavage fluid (BALf) samples from cattle by MALDI-TOF MS, omitting the cultivation step on agar plates to reduce the turnaround time between sampling and identification of pathogens. The effects of two different liquid growth media and various concentrations of bacitracin were determined to allow optimal growth of Pasteurellaceae and minimise contamination. The best procedure was validated on 100 clinical BALf samples from cattle with conventional bacterial culture as reference test. A correct identification was obtained in 73% of the samples, with 59.1% sensitivity (Se) (47.2-71.0%) and 100% specificity (Sp) (100-100%) after only 6 hours of incubation. For pure and dominant culture samples, the procedure was able to correctly identify 79.2% of the pathogens, with a sensitivity (Se) of 60.5% (45.0-76.1%) and specificity (Sp) of 100% (100-100%). In mixed culture samples, containing ≥2 clinically relevant pathogens, one pathogen could be correctly identified in 57% of the samples with 57.1% Se (38.8-75.5%) and 100% Sp (100-100%). In conclusion, MALDI-TOF MS is a promising tool for rapid pathogen identification in BALf. This new technique drastically reduces turnaround time and may be a valuable decision support tool to rationalize antimicrobial use.

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Section: Discussionmentioning

confidence: 91%

Rapid identification of respiratory bacterial pathogens from bronchoalveolar lavage fluid in cattle by MALDI-TOF MS

Driessche

Bokma

Deprez

et al. 2019

Sci Rep

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“…One solution would be to reduce the TAT required to obtain the bacterial pellet. For instance, a modified protocol using a lysis buffer resulted in a TAT of 15 min [87]. However, the time saved is at the expense of performance, as only 77.8% of the microorganisms were identified, which appears to be lower than in other studies using more complex extraction protocols [88].…”

Section: Clinical Impact and Workflow Integrationmentioning

confidence: 88%

Rapid phenotypic methods to improve the diagnosis of bacterial bloodstream infections: meeting the challenge to reduce the time to result

Dubourg

Lamy

Ruimy

2018

Clinical Microbiology and Infection

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“…MALDI-TOF MS has been used commonly for direct identification of microorganisms from positive blood cultures in clinical microbiology laboratories. There are various bacterial extraction methods for direct blood culture identification, including blood cells lysis [ 12 – 16 ], differential velocity centrifugation [ 17 ] and serum separator tubes usage [ 18 ]. Nowadays, MALDI-TOF MS has not only been used for identification of pathogens but also for detection of antimicrobial resistance [ 19 , 20 ].…”

Section: Discussionmentioning

confidence: 99%

Rapid detection of carbapenemase activity of Enterobacteriaceae isolated from positive blood cultures by MALDI-TOF MS

Liu

et al. 2018

Ann Clin Microbiol Antimicrob

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BackgroundMatrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been proved to be a useful tool for identification of pathogens directly isolated from blood cultures in clinical microbiology laboratories. β-Lactam antibiotics are commonly used for treatment of bloodstream infections caused by Enterobacteriaceae strains, and carbapenem is the superlative class of β-lactam antibiotics. Since the carbapenem resistance rate of Enterobacteriaceae strains raised year by year, efficient detection of carbapenemase activity and timely delivery of carbapenem susceptibility reports of Enterobacteriaceae strains isolated from blood cultures is important for clinicians.MethodsWe used 64 simulated blood cultures to establish the method of MALDI-TOF MS based ertapenem hydrolysis assay. The cutoff value of logRQ calculated from the peaks intensity of ertapenem and its hydrolysate was first set to identify the strains with carbapenemase activity. Then, we detected and calculated the logRQ values of 385 Enterobacteriaceae strains from positive clinical blood cultures to distinguish the carbapenemase producers and noncarbapenemase producers.ResultsThe mean logRQ value of 32 noncarbapenemase producers was − 0.85 ± 0.14 in simulated blood cultures, while the logRQ value of 32 carbapenemase producers was 0.87 ± 0.55. Thus, the cutoff value of logRQ was set at − 0.45 with sensitivity of 100% and specificity of 100%. In 385 clinical positive blood cultures, the logRQ values of all carbapenem-susceptible Enterobacteriaceae strains (81.3%, 313/385) were < − 0.45. Comparing with the detection of carbapenemase genes, carbapenem-resistant Enterobacteriaceae strains (18.7%, 72/385) were well distinguished by MALDI-TOF MS based ertapenem hydrolysis assay with a sensitivity of 92.5% and specificity of 100%.ConclusionsOur data show that MALDI-TOF MS based ertapenem hydrolysis assay is a rapid and accurate method to detect carbapenemase activity of Enterobacteriaceae strains from positive blood cultures, and can be routinely performed in clinical microbiology laboratories.

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Optimal turnaround time for direct identification of microorganisms by mass spectrometry in blood culture

Cited by 14 publications

References 11 publications

Rapid identification of respiratory bacterial pathogens from bronchoalveolar lavage fluid in cattle by MALDI-TOF MS

Rapid identification of respiratory bacterial pathogens from bronchoalveolar lavage fluid in cattle by MALDI-TOF MS

Rapid phenotypic methods to improve the diagnosis of bacterial bloodstream infections: meeting the challenge to reduce the time to result

Rapid detection of carbapenemase activity of Enterobacteriaceae isolated from positive blood cultures by MALDI-TOF MS

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