Current Limitations of Staph Infection Diagnostics, and the Role for VOCs in Achieving Culture-Independent Detection

Abstract

Staphylococci are broadly adaptable and their ability to grow in unique environments has been widely established, but the most common and clinically relevant staphylococcal niche is the skin and mucous membranes of mammals and birds. S. aureus causes severe infections in mammalian tissues and organs, with high morbidities, mortalities, and treatment costs. S. epidermidis is an important human commensal but is also capable of deadly infections. Gold-standard diagnostic methods for staph infections currently rely upon retrieval and characterization of the infectious agent through various culture-based methods. Yet, obtaining a viable bacterial sample for in vitro identification of infection etiology remains a significant barrier in clinical diagnostics. The development of volatile organic compound (VOC) profiles for the detection and identification of pathogens is an area of intensive research, with significant efforts toward establishing breath tests for infections. This review describes the limitations of existing infection diagnostics, reviews the principles and advantages of VOC-based diagnostics, summarizes the analytical tools for VOC discovery and clinical detection, and highlights examples of how VOC biomarkers have been applied to diagnosing human and animal staph infections.

Plasma-derived Extracellular Vesicles (EVs) as Biomarkers of Sepsis in Burn Patients via Label-free Raman Spectroscopy

“…[78] Current diagnostic methods rely on culture-based methods spanning multiple days, or genomic/proteomic methods which require highly specialized equipment and technicians. [79,80] Earlier diagnosis of staph infection has been shown to decrease relative mortality by 75.5%. [81] Therefore, employing a similar workflow to that described in this work for early diagnosis of staph infection via Raman could be used decrease the mortality of patients.…”

New Breath Diagnostics for Fungal Disease

“…Due to the chemical complexity of breath, various sampling, preconcentration, and analysis techniques have been investigated. For offline analyses of breath VOCs [14,15], the most common approach is to use thermal desorption tubes (TDTs) to preconcentrate and trap the VOCs for storage and transport, followed by VOC analysis using various combinations of gas chromatography (GC) and mass spectrometry (MS) techniques (e.g., gas chromatography-timeof-flight mass spectrometry) [16]. Online analyses of breath VOCs are most commonly performed using direct-injection mass spectrometry techniques such as proton transfer mass spectrometry (PTR-MS), secondary electrospray ionization mass spectrometry (SESI-MS), and selected ion flow tube mass spectrometry (SIFT-MS); details of these methods are thoroughly described in the second edition of Breathborne Biomarkers and the Human Volatilome [17 ••].…”

“…Online analyses of breath VOCs are most commonly performed using direct-injection mass spectrometry techniques such as proton transfer mass spectrometry (PTR-MS), secondary electrospray ionization mass spectrometry (SESI-MS), and selected ion flow tube mass spectrometry (SIFT-MS); details of these methods are thoroughly described in the second edition of Breathborne Biomarkers and the Human Volatilome [17 ••]. The most common instrumentation for VOC biomarker discovery and breath analysis has also recently been reviewed [16,18].…”