The Use of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for the Identification of Pathogens Causing Sepsis

Abstract

Background Sepsis is a life-threatening condition with high rates of morbidity and mortality; effective and appropriate antibiotic therapy is essential for ensuring patient improvement. To aid in the diagnosis of sepsis, blood cultures are drawn and sent to the microbiology laboratory for pathogen growth, identification, and susceptibility testing. The clinical microbiology laboratory can assist the medical team by providing timely identification of the pathogen(s) causing the bloodstream infection through the use of rapid diagnostic technology. One of these rapid diagnostic technologies, MALDI-TOF MS, has been proven to reduce the time required for appropriate antibiotic therapy when used to identify pathogens grown in culture. This technology has also been used to identify pathogens directly from the positive blood cultures with great success. Content In this minireview, we summarize the different methods that have been developed to directly identify pathogens from positive blood cultures by use of MALDI-TOF MS and the effect of this technology on patient outcomes. Additionally, we touch on current research in the field, including the identification of antimicrobial resistance directly from positive blood cultures by MALDI-TOF MS. Summary Rapid identification of pathogens is important in the survival of patients undergoing a septic event. MALDI-TOF MS technology has played an important role in rapid identification, which has led to a reduction in the time to appropriate antibiotic therapy and contributed to the improvement of patient outcomes. The high sensitivity and specificity of MALDI-TOF MS identification, in combination with MALDI-TOF's rapid function and reduced labor costs, make this technology an attractive choice for clinical laboratories.

Rapid direct identification of positive paediatric blood cultures by MALDI-TOF MS technology and its clinical impact in the paediatric hospital setting.

“…Our results suggested that narrow spectrum therapy could be advised from day one when a common pathogen with predictable susceptibility profile is identified such as Staphylococcus aureus or Enterococcus faecalis. Early confirmation of contaminated blood cultures was advantageous, leading to potential de-escalation of antibiotics along with complimentary diagnostic testing and shortening of hospital stay, in line with previous studies [2,5,22]. Although, clinical impact on infection control was not noteworthy, there was a case of N. meningitidis bacteremia which helped to early escalation of infection prevention strategies during the first phase of the study.…”

“…Sepsis is associated with high mortality [1]; hence rapid identification of bloodstream pathogens and timely clinical decision making are paramount. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized microbiology laboratories with improved workflow for pathogen identification both from solid media and positive blood culture broths [2][3][4].…”

“…Recently, several in-house protocols for direct organism identification from positive blood culture broths have been developed [2,3]. However, these protocols entail either complicated preprocessing methods or short periods of subculture to increase their accuracy [2][3][4][5][6][7][8]. As a result, these methods can be tedious and expensive [3], and remain controversial [2].…”

“…However, these protocols entail either complicated preprocessing methods or short periods of subculture to increase their accuracy [2][3][4][5][6][7][8]. As a result, these methods can be tedious and expensive [3], and remain controversial [2]. Performance rates vary, such that there is no consensus on best-practice [2,[9][10]; commercial kits are neither cost-effective nor superior in performance compared to in-house methods [12].…”

“…As a result, these methods can be tedious and expensive [3], and remain controversial [2]. Performance rates vary, such that there is no consensus on best-practice [2,[9][10]; commercial kits are neither cost-effective nor superior in performance compared to in-house methods [12]. Additionally, most studies to date have focused on adult populations and on the specific Bruker Daltonics Biotyper system [3].…”