Evaluation of a Rapid and Simplified Protocol for Direct Identification of Microorganisms From Positive Blood Cultures by Using Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

Dai, Yong; Xu, Xinyi; Xue, Yan; Li, Daming; Cao, Wenming; Tang, Lingli; Hu, Min; Jiang, Chao

doi:10.3389/fcimb.2021.632679

Cited by 7 publications

(7 citation statements)

References 39 publications

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“…The use of MALDI-TOF MS is a major innovation in microbial identification. 32 After BCs are treated with specific methods, pathogenic bacteria can be rapidly identified directly with MALDI-TOF MS. 10 , 33 , 34 Pan et al used a lysis–centrifugation–wash procedure to prepare microorganisms from positive BCs, and then directly identified them with MALDI-TOF MS, with 96.49% accuracy, consistent with our results. 35 However, not all microbiology laboratories have access to MALDI-TOF MS for bacterial identification, and must identify bacteria with conventional biochemical-reaction-based instruments.…”

Section: Discussionsupporting

confidence: 88%

Direct Identification, Antimicrobial Susceptibility Testing, and Extended-Spectrum β-Lactamase and Carbapenemase Detection in Gram-Negative Bacteria Isolated from Blood Cultures

Wen¹,

Xie²,

Liang³

et al. 2022

IDR

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Purpose To shorten the turnaround time for blood culture (BC) analyses, a rapid method was developed for the direct identification, antimicrobial susceptibility testing (AST), and multidrug resistance testing of bacteria-positive BCs. Materials and Methods The mixtures in BC bottles were treated with the multistep centrifugation method developed here and the conventional culture-based method. The bacterial sediment obtained after centrifugation was analyzed directly with MALDI-TOF MS and Vitek 2 Compact, and AST was performed directly with the Kirby–Bauer (K–B) disk diffusion, VITEK 2 Compact, and E-test methods. Extended spectrum lactamases (ESBLs) were detected with discs containing cefotaxime, cefotaxime/clavulanate, ceftazidime, and ceftazidime/clavulanate, and carbapenemase was detected with the modified carbapenem inactivation method (mCIM) and EDTA-mCIM (eCIM). Results All the results of direct testing were compared to those of the conventional methods, to evaluate the accuracy of the direct methods. The accuracies of the direct Vitek 2 Compact and MALDI-TOF MS methods were 95.5% (214/224) and 90.2% (202/224), respectively. Direct AST with K–B, Vitek 2, and E-test showed category agreement of 96.0% (2611/2721), 96.1% (2614/2721), and 97.4% (2650/2721), respectively, and the major errors and very major errors were < 2% for all three methods. In the direct determination of ESBLs, the results for cefotaxime combined with cefotaxime/clavulanate were completely consistent with those after the standard isolation method. The carbapenemase detection rate with direct mCIM and eCIM was exactly the same as that with the standard method. Conclusion These direct procedures based on multistep centrifugation are not only highly accurate but are appropriate for clinical laboratory use because the turnaround time is shorter.

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Section: Discussionsupporting

confidence: 88%

Direct Identification, Antimicrobial Susceptibility Testing, and Extended-Spectrum β-Lactamase and Carbapenemase Detection in Gram-Negative Bacteria Isolated from Blood Cultures

Wen¹,

Xie²,

Liang³

et al. 2022

IDR

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“…Bacillus bacteria can be lethal pathogens used as biological weapons, cause opportunistic infections, contaminate food, and be used as probiotics. , In addition, Bacillus species can produce a variety of extracellular enzymes such as amylase, protease, lipase, and lecithinase, so they can potentially grow and spoil a variety of food matrices. , Reference spectra of many Bacillus species are available in commercially available databases such as Biotyper 3.0; however, due to the presence of endospores that mix with vegetative cells, the classification and identification of spore-forming bacterial strains using MALDI-TOF MS is complicated. It was demonstrated that the variable vegetative-endospore composition of bacterial cells has a direct impact on the identification of bacteria and that the proportion of SASP ranging from 8 to 20% is inconsistent, making accurate identification of bacteria of the Bacillus species even more difficult. − …”

Section: Discussionmentioning

confidence: 99%

Implications of Sample Preparation Methods on the MALDI-TOF MS Identification of Spore-Forming Bacillus Species from Food Samples: A Closer Look at Bacillus licheniformis, Peribacillus simplex, Lysinibacillus fusiformis, Bacillus flexus, and Bacillus marisflavi

Janiszewska,

Złoch,

Pomastowski

et al. 2023

ACS Omega

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This research underscores the criticality of tailored culture conditions and incubation periods for effective and accurate identification of spore-forming bacteria: Bacillus licheniformis , Peribacillus simplex , Lysinibacillus fusiformis , Bacillus flexus , and Bacillus marisflav , isolated from food samples, utilizing the MALDI-TOF MS technique. All isolated strains were confirmed as Gram-positive bacteria from diverse genera through 16S rDNA gene sequencing. To enhance the accuracy of the identification process, the study employed an optimization strategy involving a varied incubation time (ranging from 1 to 48 h) and two distinct sample preparation approaches—direct transfer facilitated by formic acid and protein extraction via ethanol. It was observed that matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF MS) could successfully identify approximately 47% of the samples following a 24 h incubation period. The study emphasizes the critical role of sample preparation methods in enabling precise bacterial identification. Our findings reveal the necessity of tailoring the incubation time for each sample, as the optimum period for accurate identification fluctuated between 1 and 12 h. Further demonstrating the interplay between incubation time and spore quantity, our study used the Schaeffer–Fulton staining method to show that the lowest spore counts were detected between 5 and 8 h of incubation. This provides evidence that spore formation impacts bacterial identification. Our research thus deepens the understanding of spore-forming bacteria identification using MALDI-TOF MS and illuminates the various factors affecting the dependability and accuracy of this technique. Future research may explore additional variables, such as the effect of varying culture media, to further augment identification accuracy and gain a holistic understanding of spore-forming bacterial behavior in food samples. By enhancing our knowledge, these findings can substantially contribute to improving food safety and quality assurance strategies by enabling the more accurate and efficient identification of spore-forming bacteria in the food industry, thereby elevating the standards of food safety.

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“…Thanks to the use of FA instead of TFA (protocol two), the identification of Gram-positive bacteria increased to 67% and remained high for Gram-negative bacteria (88%). The latest research by Dai et al describes a fast and simplified protocol to identify microorganisms directly from blood cultures on the basis of the addition of the Triton X-100 reagent and centrifugation [ 99 ]. The results of the research show that a high level of identification was achieved for Enterobacterales (96.81%), Enterococcus (92.31%), non-fermenting Bacilli (89.07%), and Staphylococcus (88.91%) within 20 min.…”

Section: Bacteria Identificationmentioning

confidence: 99%

“Omic” Approaches to Bacteria and Antibiotic Resistance Identification

Janiszewska

Szultka‐Młyńska

Pomastowski

et al. 2022

IJMS

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The quick and accurate identification of microorganisms and the study of resistance to antibiotics is crucial in the economic and industrial fields along with medicine. One of the fastest-growing identification methods is the spectrometric approach consisting in the matrix-assisted laser ionization/desorption using a time-of-flight analyzer (MALDI-TOF MS), which has many advantages over conventional methods for the determination of microorganisms presented. Thanks to the use of a multiomic approach in the MALDI-TOF MS analysis, it is possible to obtain a broad spectrum of data allowing the identification of microorganisms, understanding their interactions and the analysis of antibiotic resistance mechanisms. In addition, the literature data indicate the possibility of a significant reduction in the time of the sample preparation and analysis time, which will enable a faster initiation of the treatment of patients. However, it is still necessary to improve the process of identifying and supplementing the existing databases along with creating new ones. This review summarizes the use of “-omics” approaches in the MALDI TOF MS analysis, including in bacterial identification and antibiotic resistance mechanisms analysis.

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Evaluation of a Rapid and Simplified Protocol for Direct Identification of Microorganisms From Positive Blood Cultures by Using Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

Cited by 7 publications

References 39 publications

Direct Identification, Antimicrobial Susceptibility Testing, and Extended-Spectrum β-Lactamase and Carbapenemase Detection in Gram-Negative Bacteria Isolated from Blood Cultures

Direct Identification, Antimicrobial Susceptibility Testing, and Extended-Spectrum β-Lactamase and Carbapenemase Detection in Gram-Negative Bacteria Isolated from Blood Cultures

Implications of Sample Preparation Methods on the MALDI-TOF MS Identification of Spore-Forming Bacillus Species from Food Samples: A Closer Look at Bacillus licheniformis, Peribacillus simplex, Lysinibacillus fusiformis, Bacillus flexus, and Bacillus marisflavi

“Omic” Approaches to Bacteria and Antibiotic Resistance Identification

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