Application of MALDI-TOF MS Profiling Coupled With Functionalized Magnetic Enrichment for Rapid Identification of Pathogens in a Patient With Open Fracture.

Jichong Ying,Tao Pan,Dichao Huang,Wenjing Gao,Chuanfan Ding,Shaoning Yu,Ling Ling

doi:10.3389/fchem.2021.672744

Abstract

Posttraumatic infections can occur in orthopedic trauma patients, especially in open fractures. Rapid and accurate identification of pathogens in orthopedic trauma is important for clinical diagnosis and antimicrobial treatment. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been successfully used for first-line identification of pathogens grown on culture plates. However, for direct analysis of liquid clinical specimens, pre-purification of the sample is necessary. Herein, we investigated the feasibility of coupling Fc-MBL@Fe3O4 enrichment with MALDI-TOF MS profiling in the identification of pathogens in liquid-cultured samples. This method is successfully used for the identification of pathogens in a patient with an open-leg fracture obtained at sea. Pathogens were enriched by Fc-MBL@Fe3O4 from briefly pre-cultured liquid media and identified by MALDI-TOF MS. We identified an opportunistic pathogen, Vibrio alginolyticus, which is uncommon in clinical orthopedic trauma infection but exists widely in the sea. Therefore, combining Fc-MBL@Fe3O4 enrichment and MALDI-TOF MS profiling has great potential for direct identification of microbes in clinical samples.

Highlights

Fe3O4; the enriched bacteria were extracted by formic acid from Fc-Mannose-binding lectin (MBL)@Fe3O4 and subjected to MALDI-TOF MS identification
The Transmission electron microscopy (TEM) images of Fc-MBL@Fe3O4 binding to S. aureus are shown in Figure 1A, which indicated the binding capability of Fc-MBL@Fe3O4 to S. aureus
The different amounts (108/107/106/105 CFU) of S. aureus in 1 ml buffer solution were enriched by Fc-MBL@Fe3O4 and identified by MALDI-TOF MS

Summary

Introduction

Serious wounds are always difficult to debride; especially, when complicated fractures are combined, the surgical treatment is often required (Morgenstern et al, 2018; Tuon et al, 2019). Posttraumatic infections can occur in orthopedic trauma patients when it is not treated in a timely manner or after surgical treatment (Arnold et al, 2013; Yun et al, 2016; Backes et al, 2018). Rapid identification of pathogenic bacteria in orthopedic trauma, especially open fractures, guides the clinical diagnosis and antimicrobial treatment (Yun et al, 2016; Patrulea et al, 2020). Superficial wound swabs or deep fluid samples are always sent to the clinical microbiology lab for bacterial identification

Methods

Results

Conclusion