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Cambridge Researchers in UK Develop ‘Unknome Database’ That Ranks Proteins by How Little is Known about Their Functions

Scientists believe useful new clinical laboratory assays could be developed by better understanding the huge number of ‘poorly researched’ genes and the proteins they build

Researchers have added a new “-ome” to the long list of -omes. The new -ome is the “unknome.” This is significant for clinical laboratory managers because it is part of an investigative effort to better understand the substantial number of genes, and the proteins they build, that have been understudied and of which little is known about their full function.

Scientists at the Medical Research Council Laboratory of Molecular Biology (MRC-LMB) in Cambridge, England, believe these genes are important. They have created a database of thousands of unknown—or “unknome” as they cleverly dubbed them—proteins and genes that have been “poorly understood” and which are “unjustifiably neglected,” according to a paper the scientist published in the journal PLOS Biology titled, “Functional Unknomics: Systematic Screening of Conserved Genes of Unknown Function.”

The Unknome Database includes “thousands of understudied proteins encoded by genes in the human genome, whose existence is known but whose functions are mostly not,” according to a news release.

The database, which is available to the public and which can be customized by the user, “ranks proteins based on how little is known about them,” the PLOS Biology paper notes.

It should be of interest to pathologists and clinical laboratory scientists. The fruit of this research may identify additional biomarkers useful in diagnosis and for guiding decisions on how to treat patients.

Sean Munro, PhD

“These uncharacterized genes have not deserved their neglect,” said Sean Munro, PhD (above), MRC Laboratory of Molecular Biology in Cambridge, England, in a press release. “Our database provides a powerful, versatile and efficient platform to identify and select important genes of unknown function for analysis, thereby accelerating the closure of the gap in biological knowledge that the unknome represents.” Clinical laboratory scientists may find the Unknome Database intriguing and useful. (Photo copyright: Royal Society.)

Risk of Ignoring Understudied Proteins

Proteomics (the study of proteins) is a rapidly advancing area of clinical laboratory testing. As genetic scientists learn more about proteins and their functions, diagnostics companies use that information to develop new assays. But did you know that researchers tend to focus on only a small fraction of the total number of protein-coding DNA sequences contained in the human genome?

The study of proteomics is primarily interested in the part of the genome that “contains instructions for building proteins … [which] are essential for development, growth, and reproduction across the entire body,” according to Scientific American. These are all protein-coding genes.

Proteomics estimates that there are more than two million proteins in the human body, which are coded for 20,000 to 25,000 genes, according to All the Science.

To build their database, the MRC researchers ranked the “unknome” proteins by how little is known about their functions in cellular processes. When they tested the database, they found some of these less-researched proteins important to biological functions such as development and stress resistance. 

“The role of thousands of human proteins remains unclear and yet research tends to focus on those that are already well understood,” said Sean Munro, PhD, MRC Laboratory of Molecular Biology in Cambridge, England, in the news release. “To help address this we created an Unknome database that ranks proteins based on how little is known about them, and then performed functional screens on a selection of these mystery proteins to demonstrate how ignorance can drive biological discovery.”

Munro created the Unknome Database along with Matthew Freeman, PhD, Head of England’s Sir William Dunn School of Pathology, University of Oxford.

In the paper, they acknowledged the human genome encodes about 20,000 proteins, and that the application of transcriptomics and proteomics has “confirmed that most of these new proteins are expressed, and the function of many of them has been identified.

“However,” the authors added, “despite over 20 years of extensive effort, there are also many others that still have no known function.”

They also recognized limited resources for research and that a preference for “relative safety” and “well-established fields” are likely holding back discoveries.

The researchers note “significant” risks to continually ignoring unexplored proteins, which may have roles in cell processes, serve as targets for therapies, and be associated with diseases as well as being “eminently druggable,” Genetic Engineering News reported.

Setting up the Unknome Database

To develop the Unknome Database, the researchers first turned to what has already come to fruition. They gave each protein in the human genome a “knownness” score based on review of existing information about “function, conservation across species, subcellular localization, and other factors,” Interesting Engineering reported.

It turns out, 3,000 groups of proteins (805 with a human protein) scored zero, “showing there’s still much to learn within the human genome,” Science News stated, adding that the Unknome Database catalogues more than 13,000 protein groups and nearly two million proteins. 

The researchers then tested the database by using it to determine what could be learned about 260 “mystery” genes in humans that are also present in Drosophila (small fruit flies).

“We used the Unknome Database to select 260 genes that appeared both highly conserved and particularly poorly understood, and then applied functional assays in whole animals that would be impractical at genome-wide scale,” the researchers wrote in PLOS Biology.

“We initially selected all genes that had a knownness score of ≤1.0 and are conserved in both humans and flies, as well as being present in at least 80% of available metazoan genome sequences. … After testing for viability, the nonessential genes were then screened with a panel of quantitative assays designed to reveal potential roles in a wide range of biological functions,” they added.

“Our screen in whole organisms reveals that, despite several decades of extensive genetic screens in Drosophila, there are many genes with essential roles that have eluded characterization,” the researchers conclude.

Clinical Laboratory Testing Using the Unknome Database

Future use of the Unknome Database may involve CRISPR technology to explore functions of unknown genes, according to the PLOS Biology paper.

Munro told Science News the research team may work with other research efforts aimed at understanding “mysterious proteins,” such as the Understudied Proteins Initiative.

The Unknome Database’s ability to be customized by others means researchers can create their own “knownness” scores as it applies to their studies. Thus, the database could be a resource in studies of treatments or medications to fight diseases, Chemistry World noted.

According to a statement prepared for Healthcare Dive by SomaLogic, a Boulder, Colorado-based protein biomarker company, diagnostic tests that measure proteins can be applied to diseases and conditions such as:

In a study published in Science Translational Medicine, SomaLogic’s SomaScan assay was reportedly successful in predicting the likelihood within four years of myocardial infarction, heart failure, stroke, and even death.

“The 27-protein model has potential as a ‘universal’ surrogate end point for cardiovascular risk,” the researchers wrote in Science Translational Medicine.

Proteomics definitely has its place in clinical laboratory testing. The development of MRC-LMB’s Unknome Database will help researchers’ increase their knowledge about the functions of more proteins which should in turn lead to new diagnostic assays for labs.

—Donna Marie Pocius

Related Information:

Mapping the ‘Unknome’ May Reveal Critical Genes Scientists Have Ignored

How Many Proteins Exist?

Unknome: A Database of Human Genes We Know Almost Nothing About

Functional Unknomics: Systematic Screening of Conserved Genes of Unknown Function

Unknome Database Ranks Proteins Based on How Little is Known about Them

How a New Database of Human Genes Can Help Discover New Biology

The Unknome Catalogs Nearly Two Million Proteins. Many are Mysterious

Into the Unknome: Scientists at MRC LMB in Cambridge Create Database Ranking Human Proteins by How Little We know About Them

Scientists Hope to Illuminate Unknown Human Proteins with New Public Database

Proteomic Tests Empower Precision Medicine

A Proteomic Surrogate for Cardiovascular Outcomes That is Sensitive to Multiple Mechanisms of Change in Risk

Northwestern University Study Shares News Insights into Aging Guided by Transcriptome, Gene Length Imbalance

Findings could lead to deeper understanding of why we age, and to medical laboratory tests and treatments to slow or even reverse aging

Can humans control aging by keeping their genes long and balanced? Researchers at Northwestern University in Evanston, Illinois, believe it may be possible. They have unveiled a “previously unknown mechanism” behind aging that could lead to medical interventions to slow or even reverse aging, according to a Northwestern news release.

Should additional studies validate these early findings, this line of testing may become a new service clinical laboratories could offer to referring physicians and patients. It would expand the test menu with assays that deliver value in diagnosing the aging state of a patient, and which identify the parts of the transcriptome that are undergoing the most alterations that reduce lifespan.

It may also provide insights into how treatments and therapies could be implemented by physicians to address aging.

The Northwestern University scientists published their findings in the journal Nature Aging title, “Aging Is Associated with a Systemic Length-Associated Transcriptome Imbalance.”

“I find it very elegant that a single, relatively concise principle seems to account for nearly all of the changes in activity of genes that happen in animals as they change,” Thomas Stoeger, PhD, postdoctoral scholar in the Amaral Lab who led the study, told GEN. Clinical laboratories involved in omics research may soon have new anti-aging diagnostic tests to perform. (Photo copyright: Amaral Lab.)

Possible ‘New Instrument’ for Biological Testing

Researchers found clues to aging in the length of genes. A gene transcript length reveals “molecular-level changes” during aging: longer genes relate to longer lifespans and shorter genes suggest shorter lives, GEN summarized.

The phenomenon the researchers uncovered—which they dubbed transcriptome imbalance—was “near universal” in the tissues they analyzed (blood, muscle, bone, and organs) from both humans and animals, Northwestern said. 

According to the National Human Genome Research Institute fact sheet, a transcriptome is “a collection of all the gene readouts (aka, transcript) present in a cell” shedding light on gene activity or expression.

The Northwestern study suggests “systems-level” changes are responsible for aging—a different view than traditional biology’s approach to analyzing the effects of single genes.

“We have been primarily focusing on a small number of genes, thinking that a few genes would explain disease,” said Luis Amaral, PhD, Senior Author of the Study and Professor of Chemical and Biological Engineering at Northwestern, in the news release.

“So, maybe we were not focused on the right thing before. Now that we have this new understanding, it’s like having a new instrument. It’s like Galileo with a telescope, looking at space. Looking at gene activity through this new lens will enable us to see biological phenomena differently,” Amaral added.

In their Nature Aging paper, Amaral and his colleagues wrote, “We hypothesize that aging is associated with a phenomenon that affects the transcriptome in a subtle but global manner that goes unnoticed when focusing on the changes in expression of individual genes.

“We show that transcript length alone explains most transcriptional changes observed with aging in mice and humans,” they continued.

Researchers Turn to AI, RNA Sequencing

According to their published study, the Northwestern University scientists used large datasets, artificial intelligence (AI), and RNA (ribonucleic acid) sequencing in their analysis of tissue derived from:

  • Humans (men and women), age 30 to 49, 50 to 69, and 70 years and older. 
  • Mice, age four months to 24 months.
  • Rats, age six to 24 months.
  • Killifish, age five weeks to 39 weeks.

Scientific American reported the following study findings:

  • In tissues studied, older animals’ long transcripts were not as “abundant” as short transcripts, creating “imbalance.”
  • “Imbalance” likely prohibited the researchers’ discovery of a “specific set of genes” changing.
  • As animals aged, shorter genes “appeared to become more active” than longer genes.
  • In humans, the top 5% of genes with the shortest transcripts “included many linked to shorter life spans such as those involved in maintaining the length of telomeres.”
  • Conversely, the researchers’ review of the leading 5% of genes in humans with the longest transcripts found an association with long lives.
  • Antiaging drugs—rapamycin (aka, sirolimus) and resveratrol—were linked to an increase in long-gene transcripts.

“The changes in the activity of genes are very, very small, and these small changes involve thousands of genes. We found this change was consistent across different tissues and in different animals. We found it almost everywhere,” Thomas Stoeger, PhD, postdoctoral scholar in the Amaral Lab who led the study, told GEN.

In their paper, the Northwestern scientists noted implications for creation of healthcare interventions.

“We believe that understanding the direction of causality between other age-dependent cellular and transcriptomic changes and length-associated transcriptome imbalance could open novel research directions for antiaging interventions,” they wrote.

Other ‘Omics’ Studies

Dark Daily has previously reported on transcriptomics studies, along with research into the other “omics,” including metabolomics, proteomics, and genomics.

In “Spatial Transcriptomics Provide a New and Innovative Way to Analyze Tissue Biology, May Have Value in Surgical Pathology,” we explored how newly combined digital pathology, artificial intelligence (AI), and omics technologies are providing anatomic pathologists and medical laboratory scientists with powerful diagnostic tools.

In “Swiss Researchers Develop a Multi-omic Tumor Profiler to Inform Clinical Decision Support and Guide Precision Medicine Therapy for Cancer Patients,” we looked at how new biomarkers for cancer therapies derived from the research could usher in superior clinical laboratory diagnostics that identify a patient’s suitability for personalized drug therapies and treatments.

And in “Human Salivary Proteome Wiki Developed at University of Buffalo May Provide Biomarkers for New Diagnostic Tools and Medical Laboratory Tests,” we covered how proteins in human saliva make up its proteome and may be the key to new, precision medicine diagnostics that would give clinical pathologists new capabilities to identify disease.

Fountain of Youth

While more research is needed to validate its findings, the Northwestern study is compelling as it addresses a new area of transcriptome knowledge. This is another example of researchers cracking open human and animal genomes and gaining new insights into the processes supporting life.

For clinical laboratories and pathologists, diagnostic testing to reverse aging and guide the effectiveness of therapies may one day be possible—kind of like science’s take on the mythical Fountain of Youth.  

—Donna Marie Pocius

Related Information:

Aging Is Driven by Unbalanced Genes

Aging Linked to Gene Length Imbalance and Shift Towards Shorter Genes

NIH: Transcriptome Fact Sheet

Aging Is Associated with a Systemic Length-Associated Transcriptome Imbalance

Aging Is Linked to More Activity in Short Genes than in Long Genes

Spatial Transcriptomics Provide a New and Innovative Way to Analyze Tissue Biology, May Have Value in Surgical Pathology

Swiss Researchers Develop a Multi-omic Tumor Profiler to Inform Clinical Decision Support and Guide Precision Medicine Therapy for Cancer Patients

Human Salivary Proteome Wiki Developed at University of Buffalo May Provide Biomarkers for New Diagnostic Tools and Medical Laboratory Tests

University of Washington Researchers Use Genomic Analysis to Track Shigella Infections as Decreased Cost of Gene Sequencing Aids Public Health Research

Another study in the United Kingdom that also used genomic analysis to understand drug-resistant Shigella produced findings that may be useful for microbiologists and medical laboratory scientists

From the onset of an infectious disease outbreak, public health officials, microbiologists, and clinical laboratory managers find it valuable to trace the origin of the spread back to the “index case” or “patient zero”—the first documented patient in the disease epidemic. Given the decreased cost of genomic analysis and improved accuracy of gene sequencing, infectious disease researchers are finding that task easier and faster than ever.

One recent example is a genomic study conducted at University of Washington (UW) in Seattle that enabled researchers to “retrace” the origin and spread of a “multidrug-resistant Shigellosis outbreak” from 2017 to 2022. “The aim of the study was to better understand the community transmission of Shigella and spread of antimicrobial resistance in our population, and to treat these multi-drug resistant infections more effectively,” the UW scientists stated in a new release.

Shigellosis (aka, bacillary dysentery) is a highly contagious disease of the intestines that can lead to hospitalization. Symptoms include fever, stomach cramps, diarrhea, dysentery, and dehydration.

“Additional analysis of the gut pathogen and its transmission patterns helped direct approaches to testing, treatment, and public health responses,” the UW news release states.

Usually prevalent in countries with public health and sanitation limitations, the “opportunistic” Shigella pathogen is now being seen in high-income countries as well, UW reported.

The researchers published their findings in Lancet Infectious Diseases, titled, “Genomic Reconstruction and Directed Interventions in a Multidrug-Resistant Shigellosis Outbreak in Seattle, WA, USA: A Genomic Surveillance Study.”

Ferric Fang, MD

“You can’t really expect an infectious disease to remain confined to a specific at-risk population. [Shigella infections are] very much an emerging threat and something where our public health tools and therapeutic tools have significant limitations,” infectious disease specialist Ferric Fang, MD (above) told CIDRAP News. Fang is a UW professor of Microbiology and Clinical Laboratory Medicine and a corresponding author of the UW study. (Photo copyright: University of Washington.)

Why are Shigella Cases Increasing?

The US Centers for Disease Control and Prevention (CDC) records more than 450,000 shigellosis infections each year in the US. The most common species in the US, according to CDC statistics, is Shigellaa sonnei.

Other members of the genus include:

Generally, Shigella infects children, travelers, and men who have sex with men (MSM), the CDC noted.

The UW researchers were motivated to study Shigella when they noticed an uptick in drug-resistant shigellosis cases in Seattle’s homeless population in 2020 at the beginning of the COVID-19 pandemic, Center for Infectious Disease Research and Policy News (CIDRAP News) reported.

“Especially during the pandemic, a lot of public facilities were closed that homeless people were used to using,” infectious disease specialist Ferric Fang, MD, told CIDRAP News. Fang is Professor of Microbiology and Laboratory Medicine at University of Washington and corresponding author of the UW study.

The researchers studied 171 cases of Shigella identified from 2017 to 2022 by clinical laboratories at Harborview Medical Center and UW Medical Center in Seattle. According to CIDRAP News, the UW researchers found that:

  • 46% were men who have sex with men (MSM).
  • 51% were people experiencing homelessness (PEH).
  • Fifty-six patients were admitted to the hospital, with eight to an intensive care unit.
  • 51% of isolates were multi-drug resistant (MDR).

Whole-Genome Sequencing Reveals Origin

The UW scientists characterized the stool samples of Shigella isolates by species identification, phenotypic susceptibility testing, and whole-genome sequencing, according to their Lancet Infectious Diseases paper. The paper also noted that 143 patients received antimicrobial therapy, and 70% of them benefited from the treatment for the Shigella infection.

Whole-genome sequencing revealed that two strains of Shigella (S. flexneri and S. sonnei) appeared first in Seattle’s MSM population before infecting the PEM population.

The genomic analysis found the outbreak of drug-resistant Shigella had international links as well, according to CIDRAP News:

  • One S. flexneri isolate was associated with a multi-drug resistant (MDR) strain from China, and
  • S. sonnei isolates resembled a strain characteristic of a current outbreak of MDR Shigella in England.

“The most prevalent lineage in Seattle was probably introduced to Washington State via international travel, with subsequent domestic transmission between at-risk groups,” the researchers wrote.

“Genomic analysis elucidated not only outbreak origin, but directed optimal approaches to testing, treatment, and public health response. Rapid diagnostics combined with detailed knowledge of local epidemiology can enable high rates of appropriate empirical therapy even in multidrug-resistant infection,” they continued.

UK Shigella Study Also Uses Genomics

Another study based in the United Kingdom (UK) used genomic analysis to investigate a Shigella outbreak as well.

Motivated by a UK Health Security Agency report of an increase in drug-resistance to common strains since 2021, the UK researchers studied Shigella cases from September 2015 to June 2022.

According to a paper they published in Lancet Infectious Diseases, the UK researchers “reported an increase in cases of sexually transmitted S. flexneri harboring blaCTX-M-27 (an antibiotic-resistant gene) in England, which is known to confer resistance to third-generation cephalosporins (antibiotics),” the researchers wrote.

Their analysis of plasmids (DNA with genes having antibiotic resistance) revealed a link in two drug-resistant Shigella strains at the same time, CIDRAP News explained.

“Our study reveals a worsening outlook regarding antimicrobial-resistant Shigella strains among MSM and highlights the value of continued integration of genomic analysis into surveillance and research,” the UK-based scientists wrote.

Current challenges associated with Shigella, especially as it evades treatment, may continue to demand attention from microbiologists, clinical laboratory scientists, and infectious disease specialists. Fortunately, use of genomic analysis—due to its ongoing improvements that have lowered cost and improved accuracy—has made it possible for public health researchers to better track the origins of disease outbreak and spread.    

Donna Marie Pocius

Related Information:

Genomic Reconstruction and Directed Interventions in a Multidrug-Resistant Shigellosis Outbreak in Seattle, Washington, USA: a Genomic Surveillance Study.

Genomics Aids Study of Seattle 2017-22 Shigella Outbreak

Q/A: Shigella—Shigellosis

A Spotlight on Growing Threat of Drug-Resistant Shigella

Emergence of Extensively Drug-Resistant and Multidrug-Resistant Shigella flexneri serotype 2a Associated with Sexual Transmission Among Gay, Bisexual, and Other Men Who Have Sex with Men, in England: A Descriptive Epidemiological Study

Two University of North Carolina School of Medicine Laboratories Develop Technique for Seeing How Proteins Change Shape In Vivo

UNC’s novel way to visualize the human proteome could lead to improved clinical laboratory tests along with the development of new therapies

Diagnostic testing based on proteomics is considered to be a field with immense potential in diagnostics and therapeutics. News of a research breakthrough into how scientists can visualize protein activity within cells will be of major interest to the pathologists, PhDs, and medical laboratory scientists who specialize in clinical laboratory testing involving proteins.

Proteins are essential to all life and to the growth, maintenance, and repair of the human body. So, a thorough understanding of how they function within living cells would be essential to informed medical decision-making as well. And yet, how proteins go about doing their work is not well understood.

That may soon change. Scientists at the University of North Carolina (UNC) School of Medicine have developed an imaging method that could provide new insights into how proteins alter their shapes within living cells. And those insights may lead to the development of new therapies and medical treatments.

Dubbed “binder-tag” by the UNC scientists, their new technique “allows researchers to pinpoint and track proteins that are in a desired shape or ‘conformation,’ and to do so in real time inside living cells,” according to a UNC Health news release.

Two labs in the UNC School of Medicine’s Department of Pharmacology collaborated to develop the binder-tag technique:

The scientists published their findings in the journal Cell, titled, “Biosensors Based on Peptide Exposure Show Single Molecule Conformations in Live Cells.”

Klaus Hahn PhD
 
“No one has been able to develop a method that can do, in such a generalizable way, what this method does. So, I think it could have a very big impact,” said lead author of the UNC study Klaus Hahn PhD (above), in the news release. “With this method we can see, for example, how microenvironmental differences across a cell affect, often profoundly, what a protein is doing,” he added. This research may enlarge scientists’ understanding of how the human proteome works and could lead to new medical laboratory tests and therapeutic drugs. (Photo copyright: UNC School of Medicine.)
 

How Binder-Tag Works

During their study, the UNC scientists developed binder-tag “movies” that allow viewers to see how the binder-tag technique enables the tracking of active molecules in living cells.

According to Cosmos:

  • The technique involves two parts: a fluorescent binder and a molecular tag that is attached to the proteins of interest.
  • When inactive, the tag is hidden inside the protein, but when the protein is ready for action it changes shape and exposes the tag.
  • The binder then joins with the exposed tag and fluoresces. This new fluorescence can easily be tracked within the cell.
  • Nothing else in the cell can bind to the binder or tag, so they only light up when in contact on the active protein.
  • This type of visualization will help researchers understand the dynamics of a protein in a cell.

“The method is compatible with a wide range of beacons, including much more efficient ones than the interacting beacon pairs required for ordinary FRET [fluorescence resonance energy transfer]. Binder-tag can even be used to build FRET sensors more easily. Moreover, the binder-tag molecules were chosen so that nothing in cells can react with them and interfere with their imaging role,” Hahn said in the news release.

“Only upon exposure can the peptide specifically interact with a reporter protein (the binder). Thus, simple fluorescence localization reflects protein conformation. Through direct excitation of bright dyes, the trajectory and conformation of individual proteins can be followed,” the UNC researchers wrote in Cell. “The simplicity of binder-tag can provide access to diverse proteins.”  

The UNC researchers’ binder-tag technique is a way to overcome the dire challenge of seeing tiny and hard-working proteins, Cosmos noted. Typical light microscopy does not enable a view of molecules at work. This paves the way for the new binder-tag technique, UNC pointed out.

“With this method, we can see, for example, how microenvironmental differences across a cell affect—and often profoundly—what a protein is doing,” Hahn said. “For a lot of protein-related diseases, scientists haven’t been able to understand why proteins start to do the wrong thing. The tools for obtaining that understanding just haven’t been available.”

More Proteins to Study

More research is needed before the binder-tag method can be used in diagnostics. Meanwhile, the UNC scientists intend to show how binder-tag can be applied to other protein structures and functions. 

“The human proteome has between 80,000 and 400,000 proteins, but not all at one time. They are expressed by 20,000 to 25,000 human genes. So, the human proteome has great promise for use in diagnostics, understanding disease, and developing therapies,” said Robert Michel, Editor-in-Chief of Dark Daily and its sister publication The Dark Report.

Medical scientists and diagnostics professionals will want to stay tuned to discover more about the tiny—though mighty—protein’s contributions to understanding diseases and patient treatment.     

Donna Marie Pocius

Related Information:

Biosensors Based on Peptide Exposure Show Single Molecule Conformations in Live Cells

Powerful Technique Allows Scientists to Study How Proteins Change Shape Inside Cells

Watching Proteins Dance

Binder-Tag: A Versatile Approach to Probe and Control the Conformational Changes of Individual Molecules in Living Cells

Wellcome Sanger Institute Study Discovers New Strain of C. Difficile That Targets Sugar in Hospital Foods and Resists Standard Disinfectants

Researchers believe new findings about genetic changes in C. difficile are a sign that it is becoming more difficult to eradicate

Hospital infection control teams, microbiologists, and clinical laboratory professionals soon may be battling a strain of Clostridium difficile (C. difficile) that is even more resistant to disinfectants and other forms of infection control.

That’s the opinion of research scientists at the Wellcome Sanger Institute (WSI) and the London School of Hygiene and Tropical Medicine (LSHTM) in the United Kingdom who discovered the “genetic changes” in C. difficile. Their genomics study, published in Nature Genetics, shows that the battle against super-bugs could be heating up.

A WSI news release states the researchers “identified genetic changes in the newly-emerging species that allow it to thrive on the Western sugar-rich diet, evade common hospital disinfectants, and spread easily.”

Microbiologists and infectious disease doctors know full well that this means the battle to control HAIs is far from won.

C. difficile is currently forming a new species with one group specialized to spread in hospital environments. This emerging species has existed for thousands of years, but this is the first time anyone has studied C. difficile genomics in this way to identify it. This particular [bacterium] was primed to take advantage of modern healthcare practices and human diets,” said Nitin Kumar, PhD (above), in the news release. (Photo copyright: Wellcome Sanger Institute.) 

Genomic Study Finds New Species of Bacteria Thrive in Western Hospitals

In the published paper, Nitin Kumar, PhD, Senior Bioinformatician at the Wellcome Sanger Institute and Joint First Author of the study, described a need to better understand the formation of the new bacterial species. To do so, the researchers first collected and cultured 906 strains of C. difficile from humans, animals, and the environment. Next, they sequenced each DNA strain. Then, they compared and analyzed all genomes.

The researchers found that “about 70% of the strain collected specifically from hospital patients shared many notable characteristics,” the New York Post (NYPost) reported.

Hospital medical laboratory leaders will be intrigued by the researchers’ conclusion that C. difficile is dividing into two separate species. The new type—dubbed C. difficile clade A—seems to be targeting sugar-laden foods common in Western diets and easily spreads in hospital environments, the study notes. 

“It’s not uncommon for bacteria to evolve, but this time we actually see what factors are responsible for the evolution,” Kumar told Live Science.

New C. Difficile Loves Sugar, Spreads

Researchers found changes in the DNA and ability of the C. difficile clade A to metabolize simple sugars. Common hospital fare, such as “the pudding cups and instant mashed potatoes that define hospital dining are prime targets for these strains”, the NYPost explained.

Indeed, C. difficile clade A does have a sweet tooth. It was associated with infection in mice that were put on a sugary “Western” diet, according to the Daily Mail, which reported the researchers found that “tougher” spores enabled the bacteria to fight disinfectants and were, therefore, likely to spread in healthcare environments and among patients.

“The new C. difficile produces spores that are more resistant and have increased sporulation and host colonization capacity when glucose or fructose is available for metabolism. Thus, we report the formation of an emerging C. difficile species, selected for metabolizing simple dietary sugars and producing high levels or resistant spores, that is adapted for healthcare-mediated transmission,” the researchers wrote in Nature Genetics.

Bacteria Pose Risk to Patients

The findings about the new strains of C. difficile bacteria now taking hold in provider settings are important because hospitalized patients are among those likely to develop life-threatening diarrhea due to infection. In particular, people being treated with antibiotics are vulnerable to hospital-acquired infections, because the drugs eliminate normal gut bacteria that control the spread of C. difficile bacteria, the researchers explained.

According to the Centers for Disease Control and Prevention (CDC), C. difficile causes about a half-million infections in patients annually and 15,000 of those infections lead to deaths in the US each year.

New Hospital Foods and Disinfectants Needed

The WSI/LSHTM study suggests hospital representatives should serve low-sugar diets to patients and purchase stronger disinfectants. 

“We show that strains of C. difficile bacteria have continued to evolve in response to modern diets and healthcare systems and reveal that focusing on diet and looking for new disinfectants could help in the fight against this bacteria,” said Trevor Lawley, PhD, Senior Author and Group Leader of the Lawley Lab at the Wellcome Sanger Institute, in the news release.

Microbiologists, infectious disease physicians, and their associates in nutrition and environmental services can help by understanding and watching development of the new C. difficile species and offering possible therapies and approaches toward prevention.

Meanwhile, clinical laboratories and microbiology labs will want to keep up with research into these new forms of C. difficile, so that they can identify the strains of this bacteria that are more resistant to disinfectants and other infection control methods.  

—Donna Marie Pocius

Related Information:

Adaptation of Host Transmission Cycle During Clostridium Difficile Speciation

Diarrhea-causing Bacteria Adapted to Spread in Hospitals

Sugary Western Diets Fuel Newly Evolving Superbug

New Carb-Loving Superbug is Primed to Target Hospital Food

Superbug C Difficile Evolving to Spread in Hospitals and Feeds on the Sugar-Rich Western Diet

CDC: Healthcare-Associated Infections-C. Difficile  

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