Traditional diagnostic methods for bacterial infections often rely on blood cultures, imaging approaches, and molecular assays. Although effective, these techniques suffer from significant limitations: they can be slow, often taking days to yield results; lack specificity in differentiating bacterial pathogens; or entail considerable expense and infrastructure, restricting their accessibility. These drawbacks compromise timely decision-making, which is critical for administering appropriate therapy, especially in emergency settings. Recognizing these gaps, the research team led by David Wilson developed a novel breath test approach inspired by existing diagnostics for Helicobacter pylori, a bacterium causing stomach infections.

The classic H. pylori breath test involves patients consuming a substrate labeled with a traceable isotope, which the bacteria metabolize into labeled carbon dioxide detectable in exhaled breath. Borrowing from this concept, Wilson and colleagues sought to broaden the scope by identifying compounds specifically metabolized by a wider array of bacteria while remaining largely inert to human metabolism. Their innovative strategy hinged on the use of sugars and sugar alcohols tagged with carbon-13, a stable, non-radioactive isotope. Because human cells metabolize these compounds less efficiently than bacteria, the presence of carbon-13-labeled carbon dioxide in breath would serve as a direct indicator of bacterial activity.

To validate their concept, the researchers conducted meticulous laboratory assays to screen various carbon-13-tagged substrates. They confirmed several candidates that are preferentially metabolized by clinically relevant bacteria, producing carbon-13-enriched carbon dioxide as a metabolic byproduct. For sensitive detection, the team employed nondispersive infrared spectroscopy—a cost-effective, portable analytical method capable of quantifying isotope-labeled gases in real time. This synergistic combination of isotope-labeled substrates and infrared detection formed the cornerstone of their breath testing prototype.

Animal models of infection provided compelling proof of concept. Mice infected with bacterial pathogens causing pneumonia, bloodstream infections, muscle infections, and osteomyelitis were intravenously administered the carbon-13-labeled compounds. Within minutes, breath samples from infected mice exhibited significantly elevated levels of carbon-13-labeled carbon dioxide compared to uninfected controls, whose breath signals remained near baseline. Intriguingly, results showed that the breath-based signal typically appeared within the first 10 minutes post substrate administration, highlighting the remarkable rapidity of this diagnostic approach.

Moreover, the team demonstrated the breath test’s potential utility as a real-time monitor of therapeutic efficacy. In one model of Escherichia coli infection, measurements of labeled carbon dioxide in breath decreased progressively as antibiotic treatment suppressed bacterial proliferation. This real-time feedback could enable clinicians not only to confirm bacterial infections rapidly but also to track treatment response non-invasively, potentially allowing for individualized therapy adjustments with unprecedented speed.

Beyond performance, safety and practicality were also at the forefront. The sugars and sugar alcohols chosen are generally recognized as safe for human use, with established pharmacokinetics and minimal toxicity. Coupled with compact, portable instruments for breath analysis, the envisioned diagnostic platform could be deployed in a variety of clinical environments—from emergency rooms to outpatient clinics—without requiring extensive laboratory infrastructure. This portability promises to drastically reduce turnaround times for infection diagnosis.

Despite the exciting results, the researchers underscore that their preliminary investigation has not yet optimized the breath test protocol. Future studies aim to fine-tune substrate selection and dosing, enhance breath sampling techniques, and validate the approach in humans. Their vision is for a non-invasive, rapid breath test that can provide immediate diagnostic clarity for bacterial infections, assisting clinicians in making prompt and appropriate treatment decisions in critical scenarios.

The implications of this study extend beyond diagnostic speed. By enabling point-of-care detection of bacterial infections, such breath-based tests could diminish unnecessary antibiotic prescriptions, thereby combating the global threat of antibiotic resistance. The capability to monitor treatment response in near real-time may foster judicious use of antimicrobials, improve patient outcomes, and reduce healthcare costs. Additionally, the non-invasive nature of breath sampling represents a significant patient comfort improvement compared to blood draws or invasive biopsies.

Supported by funding from the National Institutes of Health and the Cystic Fibrosis Foundation, this venture capitalizes on interdisciplinary collaboration, merging microbiology, analytical chemistry, and clinical medicine. The authors have taken steps to secure intellectual property related to this technology by filing a U.S. patent, underscoring the translational potential of their innovation.

The utilization of carbon isotopes for metabolic tracing in diagnostic applications is not new; however, tailoring this approach specifically to bacterial infection detection in breath signifies a vibrant leap forward. This research bridges fundamental chemical biology with practical healthcare solutions, charting a course for rapid, accurate, and patient-friendly diagnostics. As the global community grapples with emerging infectious threats and antimicrobial resistance, advances like these are crucial for reshaping the future of medicine.

Through this novel technology, scientists harness the metabolic footprints of bacteria to “sniff out” infections in a matter of minutes—a feat that could redefine emergency diagnostics and infectious disease management worldwide. While further clinical validation remains necessary, the vision of a simple breath test for bacterial infections draws closer to reality, promising to empower healthcare providers with faster, safer, and smarter tools to fight infection.

Subject of Research: Development of rapid, non-invasive breath tests for diagnosing bacterial infections using carbon-13-labeled substrates and infrared spectroscopy.

Article Title: Prototype breath tests spot bacterial infections in minutes

News Publication Date: 18-Mar-2026

Web References:
http://pubs.acs.org/doi/abs/10.1021/acscentsci.5c01995

Keywords:
Bacterial infections, breath test, carbon-13 isotope, nondispersive infrared spectroscopy, rapid diagnosis, pneumonia, bloodstream infection, antibiotic resistance, metabolic tracing, Escherichia coli, point-of-care diagnostics, non-invasive testing

Professor José Ramón Bilbao, a leading geneticist at EHU and co-lead author of this pivotal study, emphasizes the underappreciated potential of saliva in medical diagnostics. “Saliva is one of the most accessible biological fluids but it is still underutilised in clinical practice,” he explains. The research highlights that saliva contains molecular markers reflective of systemic pathological processes, which means it could serve as a window into diseases affecting organs and tissues far beyond the oral cavity.

The scientific team meticulously analyzed saliva samples obtained from over 350 individuals, focusing on the cataloging of single nucleotide polymorphisms (SNPs)—the minute variations in DNA sequence known to influence gene function. Their approach concentrated on determining how these polymorphisms, essentially genetic switches, modulate gene activity. These SNPs were found not just to exist in saliva but to exert functional effects that parallel those identified in blood-based studies of genome function and disease susceptibility.

A striking outcome of the research was the demonstration that many of the SNPs detected within saliva samples are significantly associated with an elevated risk for a multitude of common chronic diseases. These include, but are not limited to, prostate cancer, coronary artery disease, Parkinson’s disease, and Type 2 diabetes. This observation aligns with large-scale international genome-wide association studies (GWAS) previously conducted on blood-derived DNA, thereby validating saliva as an equivalent medium for detecting disease-relevant genetic variants.

Beyond identifying risk-associated polymorphisms, the scientists employed sophisticated statistical modeling to assess the contribution of saliva-based genetic markers to heritability estimates of complex diseases. Intriguingly, their analyses revealed that saliva-derived SNPs could explain a considerable portion of genetic heritability, in some instances outperforming traditional blood biomarkers. This raises the prospect of saliva potentially offering more precise genetic risk stratification in clinical settings.

While the research is poised to revolutionize non-invasive diagnostics, the investigators underscore the necessity for validation in expanded cohorts and diverse populations to fully establish clinical utility. Alba Hernangómez-Laderas, a molecular biologist and co-lead on the project, underscores this point: “This work opens the door to developing saliva-based testing that could in the future be used for the early detection of diseases or for monitoring treatments, without the need to extract blood or perform other invasive procedures.”

The implications of this work are both profound and practical, predicting a future where saliva-based tests become routine tools in preventive medicine and personalized healthcare. The minimal discomfort and ease of repeated sample acquisition position saliva as an ideal biofluid for longitudinal monitoring of disease progression and therapeutic response, potentially reshaping patient compliance and engagement.

An additional cornerstone of the study was the development of the largest publicly accessible genetic database derived from saliva samples. Hosted via an open-access platform, this genetic repository is designed to stimulate innovative research and foster collaboration across biomedical disciplines. Researchers worldwide will be able to leverage this resource to explore novel diagnostic markers and genetic architectures of disease.

This research forms part of a collaborative effort involving eight additional researchers from EHU and partnering institutions including BioGipuzkoa, BioBizkaia, and the Icahn School of Medicine at Mount Sinai in New York. The interdisciplinary nature of the team reflects the complexity of translating molecular genetic discoveries into clinical practice, weaving together expertise from genomics, biostatistics, and clinical medicine.

At its core, this study challenges the current paradigm that prioritizes blood samples for genome-based diagnostics. By demonstrating that saliva harbors equivalent or superior genetic information relevant to systemic diseases, it lays the groundwork for more accessible, cost-effective, and patient-friendly diagnostic methodologies. Such progress aligns with the global pursuit of precision medicine, where non-invasive, rapid, and accurate testing modalities are paramount.

The potential for saliva to act as a diagnostic medium is particularly timely given the ongoing push toward decentralized healthcare and community-based testing facilities. Saliva’s collection simplicity obviates the need for trained phlebotomists and stringent cold-chain logistics, thereby broadening access to genetic testing in underserved or remote areas, and enabling large-scale screening programs.

As exciting as these findings are, the authors caution that rigorous longitudinal studies and regulatory evaluations are required before saliva-based genetic tests can be incorporated into routine clinical protocols. Nonetheless, the foundational data generated by this study constitute a significant leap forward, elevating saliva from a diagnostic curiosity to a bona fide molecular goldmine.

In summary, this pioneering research underscores saliva’s vast promise as a non-invasive, informative, and practical surrogate for blood in genomic medicine. The identification of functional DNA methylation biomarkers within saliva heralds a new era for the early detection and management of multifactorial diseases, leveraging the genetic fingerprints embedded in our most accessible bodily fluid.

Subject of Research: Saliva as a diagnostic medium for DNA methylation biomarkers indicating disorders beyond oral health

Article Title: Saliva as a potential diagnostic medium: DNA methylation biomarkers for disorders beyond the oral cavity

News Publication Date: 20-Jun-2025

Web References:
https://doi.org/10.1038/s41525-025-00509-0

References:
Alba Hernangómez-Laderas, Ariadna Cilleros-Portet, Sergi Marí, Bárbara P. González-García, Ane Arregi, Alba Jimeno-Romero, Amaia Irizar, Iraia García-Santisteban, Corina Lesseur, Nora Fernandez-Jimenez, José Ramón Bilbao. Saliva as a potential diagnostic medium: DNA methylation biomarkers for disorders beyond the oral cavity. npj Genomic Medicine, 10, 49 (2025).

Image Credits:
Photo: Egoi Markaida. EHU

Keywords:
Saliva, Body fluids, Cancer, Cancer research, Heart disease, Parkinson’s disease

Traditionally, protein glycosylation has emerged as a crucial element in the development of novel diagnostic tools and therapeutic agents. However, researchers have long grappled with the limitations of existing N-glycoproteomic methodologies, particularly in complex biological matrices such as blood plasma. The frequent inaccuracies in glycopeptide identification, coupled with the challenges of detecting trace levels of modified N-glycans, have stymied progress in biomarker discovery. The recent research endeavors to address these deficiencies by implementing a sophisticated workflow designed to enhance the resolution and reliability of glycoproteomic analyses.

To tackle the issue of high-abundance proteins, the study initiates a meticulous depletion process targeting the top fourteen proteins that typically overshadow low-abundance glycoproteins in blood plasma samples. This step is critical as it allows for a more nuanced analysis of the proteins that may hold elusive biomarkers. Following this depletion, the workflow integrates a fractionation strategy along with tryptic digestion to further refine the sample pool, setting the stage for a comprehensive exploration of the remaining glycoproteins.

The enriched glycopeptides undergo rigorous high-resolution mass spectrometry analysis utilizing a dual fragmentation approach—stepped collision energy fragmentation (HCD.step and HCD.low). This innovative technique not only enhances the detection of glycopeptides but also provides a more detailed structural characterization. A new decision tree methodology was incorporated into the data validation process, allowing for more accurate and systematic identification of glycopeptides, thus overcoming previous hurdles in the analysis.

Impressive results emerged from the experimental workflow, as it achieved a detection sensitivity that could identify glycoproteins at concentrations as low as 6.31 pg·mL−1. This remarkable improvement represents an expansion of detection capability by an astounding five orders of magnitude compared to conventional plasma analysis methods. Such sensitivity is crucial when considering the rarity of many potential biomarkers, which often exist at extremely low concentrations within biological samples.

The comprehensive data analysis methodology employed in the study further distinguishes ambiguous N-glycan structures which foundationally enriches the understanding of glycosylation patterns. This precision enables researchers to differentiate between various glycan modifications, including antenna and core fucosylation, as well as to recognize rare entities such as sulfated and glucuronidated glycans that were previously unnoticed in routine analyses. These advancements in glycan structural analysis herald a new era in glycoproteomics, facilitating targeted studies for biomarker validation.

In total, researchers successfully identified 1929 unique N-glycopeptides along with 942 N-glycosites sourced from 805 glycoproteins deemed middle- to low-abundant. Among the significant findings, sulfated and phosphorylated N-glycopeptides were detected in prevalent HBP glycoproteins, underscoring the potential of this workflow to uncover novel glycosylation variants that could be critically relevant to health and disease states. Moreover, the study reported the discovery of three rare N-glycan building blocks identified by exact mass measurements of 176.0314, 245.0524, and 259.0672 Da—components that may play pivotal roles in cellular signaling and disease mechanisms.

The implications of this advanced workflow reach far beyond the confines of academic research. Its applicability spans various domains, from identifying novel biomarkers pertinent to disease stratification and prognosis to enhancing the characterization of biotherapeutic proteins in drug development processes. Despite the limitations noted in the study, such as extended measurement times inherent to the instrumentation used, the findings serve as a formidable foundation for future glycoproteomic investigations.

In conclusion, the innovative analysis workflow developed in this study opens new avenues for exploring the low-abundant N-glycoproteome in human blood plasma. As the understanding of protein glycosylation continues to evolve, this research paves the way for significant advancements in identifying biomarkers with the potential to revolutionize diagnostics. A deeper exploration of the glycoproteomic landscape promises to improve our comprehension of disease and health, thereby enhancing the clinical relevance of glycoproteomic studies.

The paper, titled “New Avenues for Human Blood Plasma Biomarker Discovery via Improved In-Depth Analysis of the Low-Abundant N–glycoproteome,” has been authored by Frania J. Zuniga-Banuelos and colleagues, ultimately contributing to the growing body of literature emphasizing the importance of glycosylation in health science. This seminal work elucidates how innovative methodologies can yield critical insights necessary for ongoing research and future clinical applications.

Subject of Research: N-glycoproteomic analysis in human blood plasma
Article Title: New Avenues for Human Blood Plasma Biomarker Discovery via Improved In-Depth Analysis of the Low-Abundant N–glycoproteome
News Publication Date: 1-Feb-2025
Web References: https://doi.org/10.1016/j.eng.2024.11.039
References: N/A
Image Credits: Credit: Frania J. Zuniga-Banuelos et al.

Keywords

Blood plasma, Biomarkers, Proteomic analysis, Clinical research

The current reliance on ALT and AST in both clinical practice and the drug development pipeline raises significant challenges. These enzymes can reflect liver injury but can also increase due to muscle damage or other tissue injuries. This non-specificity is particularly concerning in patient populations with pre-existing muscle conditions or in scenarios involving drug-induced muscle toxicity. As a result, clinicians often face ambiguity in diagnosing liver health based on these markers, which can delay or complicate critical treatment decisions. The introduction of GLDH could potentially resolve many of these issues, offering a tool that is specifically tailored to identifying liver damage.

The findings surrounding GLDH suggest that it performs comparably to ALT in detecting liver injury but remains unaffected by muscle injury. The implications of this discovery are clear: by utilizing GLDH as a biomarker, healthcare providers may achieve a more accurate assessment of liver damage. The research team has rigorously tested GLDH’s sensitivity and specificity, with initial studies revealing promising results. GLDH levels are less likely to be confounded by other tissue injuries, potentially paving the way for clearer clinical decisions.

Published recently in the journal Toxicological Sciences, the study offers comprehensive data on the reference ranges of GLDH within a healthy human population. The research not only confirms the reliability of GLDH as a liver-specific biomarker but also details the kinetics of GLDH in serum. The data indicates that GLDH levels decline faster than ALT after the cessation of liver injury, suggesting that monitoring GLDH could provide valuable insights into the recovery of liver health during therapeutic interventions.

Dr. Jiri Aubrecht, a key figure in the research and an adjunct professor at Georgetown University, emphasized the collaborative effort required to advance biomarker research. The study he first contributed to over a decade ago set the foundation for this more recent work, showing a remarkable evolution in our understanding of liver-specific markers. His acknowledgment of the Critical Path Institute’s support highlights the importance of fostering partnerships between academia and industry to drive innovation in drug safety assessments.

Moreover, the U.S. Food and Drug Administration (FDA) is currently evaluating this research through its Biomarker Qualification Program (BQP). This review process is crucial, as it signifies the potential for GLDH to gain acceptance as a standard liver safety biomarker in drug development and clinical practice. The successful qualification of GLDH would represent a significant step forward in addressing the crucial limitations associated with current biomarkers like ALT.

Mitch McGill, a co-author of the study and an Associate Professor at the University of Arkansas for Medical Sciences, pointed out that the reliance on ALT in clinical trials carries inherent risks. The lack of specificity can lead to misinformed clinical decisions, ultimately impacting patient safety and care. By qualifying GLDH, the research community can take the critical first step in enhancing the accuracy of liver injury detection, paving the way for better management of drug-related liver toxicity.

The importance of this research extends beyond biomarkers; it signifies a developing understanding of liver pathophysiology and its implications in drug development. As pharmaceutical companies strive to improve drug safety while minimizing adverse effects, the adoption of more specific biomarkers like GLDH can significantly enhance the monitoring of liver function. This shift could lead to more effective drug therapies, ultimately benefiting patient outcomes.

Investigating GLDH’s role in liver health necessitates a broader look at liver physiology and the biochemical pathways involved in liver injury. Understanding the mechanisms underlying these processes is critical for the deployment of GLDH in clinical settings. Historical data on liver function assays can provide insight into how this new biomarker fits within the framework of liver diagnostics, helping to elucidate the complex interplay between liver health and drug safety.

As the landscape of drug development continues to evolve, the validation of GLDH serves as a reminder of the ongoing efforts needed to refine diagnostic tools and enhance patient care. Through collaboration and innovation, the scientific community can improve our ability to monitor liver health, ultimately leading to more informed treatment strategies and better patient outcomes.

In conclusion, the proposed use of glutamate dehydrogenase as a more specific biomarker for liver injury represents a promising advancement in the field of clinical medicine and pharmacology. The validation of GLDH could transform the standard practices surrounding liver health monitoring in drug development, creating a pathway towards safer therapeutic interventions. As researchers push forward in their investigations, the integration of GLDH into clinical practices could herald a new era of precision in the diagnosis and management of liver-related conditions.

Subject of Research: People
Article Title: Serum glutamate dehydrogenase activity enables sensitive and specific diagnosis of hepatocellular injury in humans
News Publication Date: November 6, 2024
Web References: Toxicological Sciences
References: DOI: 10.1093/toxsci/kfae143
Image Credits: Not specified

Keywords

Biomarkers, Liver damage, Drug development, Drug safety, Medical tests, Clinical research, Hepatotoxicity, Biochemistry, Pharmacology, Toxicology, Drug targets.