Evaluation of Rapid Sepsityper® protocol and specific MBT-Sepsityper module (Bruker Daltonics) for the rapid diagnosis of bacteremia and fungemia by MALDI-TOF-MS

Abstract

During bloodstream infections, rapid adaptation of empirical treatment according to the microorganism identified is essential to decrease mortality. The aim of the present study was to assess the microbiological performances of a new rapid version of the Sepsityper® kit (Bruker Daltonics) allowing identification of bacteria and yeast by MALDI-TOF mass spectrometry directly from positive blood cultures in 10 min and of the specific MBT-Sepsityper module for spectra analysis, designed to increase identification performance. Identification rates were determined prospectively on 350 bacterial and 29 fungal positive blood cultures, and compared to conventional diagnostic method. Our rapid diagnosis strategy (Rapid Sepsityper® protocol: one spot with and one without formic acid extraction step) combined to MBT-Sepsityper module provided 65.4%, 78.9% and 62% reliable identification to the species level of monomicrobial positive blood cultures growing respectively Gram-positive, Gram-negative bacteria or yeast. Importantly, identification rates of Gram-positive bacteria were higher in anaerobic than in aerobic bottles (77.8% vs 22.2%; p = 0.004), if formic acid extraction step was performed (60.8% vs 39.2%; p = 1.8e−6) and if specific MBT-Sepsityper module was used (76.2% vs 61.9%, p = 0.041) while no significant differences were observed for Gram-negative bacteria. For yeasts identification, formic acid extraction step improved rapid identification rate by 37.9% while the specific MBT-Sepsityper module increased overall performances by 38%, providing up to 89.7% reliable identification if associated with the standard Sepsityper® protocol. These performances, associated with a reduce turnaround time, may help to implement a rapid identification strategy of bloodstream infections in the routine workflow of microbiology laboratories.

MALDI-TOF MS in a Medical Mycology Laboratory: On Stage and Backstage

“…We then successfully tested this home-made SDS 1.8% protocol using the same rapid protocol as the one developed later by Bruker in the Rapid Sepsityper [59]. Results were comparable to the ones obtained in the following study using Rapid Sepsityper [54,59], confirming that home-made SDS 1.8% protocol is suitable for both bacteria and yeast identifications.…”

“…Concerning yeast identification, standard Sepsityper protocol, based on ethanol and formic acid extraction appeared to be more effective than Rapid-Sepsityper. Importantly, the use of specific MBT-Sepsityper module increased the identification rates of yeasts by 38% [54]. Of note, whatever the protocol, identification rates were always higher with the addition of formic acid [54].…”

“…Importantly, the use of specific MBT-Sepsityper module increased the identification rates of yeasts by 38% [54]. Of note, whatever the protocol, identification rates were always higher with the addition of formic acid [54].…”

“…In parallel, Bruker developed a specific MBT-Sepsityper module for spectra analysis, designed to increase identification performance. In 2019, we evaluated this identification strategy (Rapid Sepsityper and MBT-Sepsityper module) from positive blood cultures [54]. Concerning yeast identification, standard Sepsityper protocol, based on ethanol and formic acid extraction appeared to be more effective than Rapid-Sepsityper.…”

Direct Rapid Identification from Positive Blood Cultures by MALDI-TOF MS: Specific Focus on Turnaround Times

“…A software module recently developed for the MALDI Biotyper, the MBT-Sepsityper module, score threshold values were lowered and determined reliably at 1.6 at the genus level and 1.8 at the species level, which was previously accepted at 1.7 and 2.0, respectively, for identification from the colony in the standard module ( 31 , 32 ). For direct identification from blood culture bottles, the MBT-Sepsityper module provided significantly higher accuracy of the identification rates compared to the standard software module ( 11 , 33 ).…”