Comparison of rapid BACpro® II, Sepsityper® kit and in-house preparation methods for direct identification of bacteria from blood cultures by MALDI-TOF MS with and without Sepsityper® module analysis

Abstract

There are several approaches available for purifying microorganisms prior to matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. In the present study, rapid BACpro® II (Nittobo Medical Co., Ltd., Tokyo, Japan), a new application, has been compared with Sepsityper® kit (Bruker Daltonics, Billerica, USA) and an in-house method. Samples were also tested with two modules, standard and Sepsityper®, identified in the Bruker MALDI-TOF MS. The bottles having monomicrobial growth were included in the study according to Gram staining results. In total, two hundred blood culture bottles were included but there was no growth in one of the subcultures so 199 blood culture bottles were studied prospectively. With the standard MALDI-TOF MS analysis, rapid BACpro® II could successfully identify microorganisms in 174/199 (87.4%) of the bottles where Sepsityper® kit and in-house method were successful in 136/199 (68.3%) and 114/199 (57.3%), respectively. When the MALDI-TOF MS data were analysed by Sepsityper® module, the identification rates were increased to 94.4%, 82.1% and 69.8% (p < 0.001), respectively. In the Sepsityper® module, 72/73 (98.6%) of Gram-negative and 97/106 (91.5%) of Grampositive microorganisms were detected by rapid BACpro® II method. The present study shows that rapid BACpro® II is a reliable preparation procedure and has higher rates of identification compared with Sepsityper® kit and in-house method. The use of the Sepsityper® module in blood cultures increases the chance of identification for all three methods studied.

Evaluation of the rapidBACpro®II kit for the rapid identification of microorganisms directly from blood cultures using MALDI-TOF MS

“…We identified 80.0% of the isolates correctly at the species level with score values ≥2.0 and 94.4% correctly at the genus level with score values ≥1.7. These results are in agreement with those obtained by Tsuchida et al (2018) and Kayin et al (2019). The enterococci (97.3%) and S. aureus (94.7%) were correctly identified with scores ≥2.0 more often than other Gram positives such as streptococci (66.3%) and coagulase negative staphylococci (59.5%).…”

“…This rate increased to 94.4% when the specific Sepsityper module for the Sepstityper kit (score value ≥1.6) was applied. Gram positives were accurately identified at the species level in 91.5% of the cases using the Sepsityper module (16).…”

Mass Spectrometry Based-Proteomic Analysis of Anisakis spp.: A Preliminary Study towards a New Diagnostic Tool

“…The technique and the expertise have been growing over time; the implementation of associated software and reference databases, as well as sample preparation kits commercialized by the vendor have allowed researchers and laboratory specialists to both increase the type of microorganisms that can be identified and potentially treat/process “direct samples” (e.g., blood cultures), facilitating the management of infected patients. As an example, Bruker has developed the MBT Sepsityper IVD Kit for the identification of microorganisms from blood cultures using a MALDI–TOF MS platform [ 18 , 19 , 20 ]. Interestingly, a recent article reported the use of the MBT Sepsityper Kit in order to profile four nematodes ( Dirofilaria repens , Dirofilaria immitis , Ascaris suum , and Ascaris lumbricoides ) [ 10 ], which intrigued and prompted us to test this method on Anisakis spp.…”

Mass spectrometry-based microbiological testing for blood stream infection

“…Although preliminary, the overall MALDI-TOF MS-based ID rates were greater with the rapid BACpro ® II than with the Sepsityper ® , with a score > 1.7 and > 2.0 obtained using the rapid BACpro ® II kit at 99.1% and 80.5%, respectively; for the Sepsityper ® kit, the percentages were 83.2% and 58.4%, respectively. The superiority of the rapid BACpro ® II was confirmed by Kaylin et al [45], who performed a three-way comparison of the two commercial kits and their home-brew method.…”