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.
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.
The proof-of-concept experiment showed data can be encoded in DNA and retrieved using automated systems, a development that may have positive significance for clinical laboratories
It may seem far-fetched, but computer scientists and research groups have worked for years to discover if it is possible to store data on Deoxyribonucleic acid (DNA). Now, Microsoft Research (MR) and the University of Washington (UW) have achieved just that, and the implications of their success could be far-reaching.
Clinical pathologists are increasingly performing genetic DNA sequencing in their medical laboratories to identify biomarkers for disease, help clinicians understand their patients’ risk for a specific disease, and track the progression of a disease. The ability to store data in DNA would take that to another level and could have an impact on diagnostic pathology. Pathologist familiar with DNA sequencing may find a whole new area of medical service open to them.
The MR/UW researchers recently demonstrated a fully automated system that encoded data into DNA and then recovered the information as digital data. “In a simple proof-of-concept test, the team successfully encoded the word ‘hello’ in snippets of fabricated DNA and converted it back to digital data using a fully automated end-to-end system,” Microsoft stated in a news release.
DNA’s Potential Storage Capacity and Why We Need It
Thus far, the challenge of using DNA for data storage has
been that there wasn’t a way to easily code and retrieve the information. That,
however, seems to be changing quite rapidly. Several major companies have
invested heavily in research, with consumer offerings expected soon.
At Microsoft Research, ‘consumer interest’ in genetic testing has driven the research into using DNA for data storage. “As People get better access to their own DNA, why not also give them the ability to read any kind of data written in DNA?” asked Doug Carmean, an Architect at Microsoft, during an interview with Wired.
Scientists are interested in using DNA for data storage because
humanity is creating more data than ever before, and the pace is accelerating.
Currently, most of that data is stored on tape, which is inexpensive, but has
drawbacks. Tape degrades and has to be replaced every 10 years or so. But DNA,
on the other hand, lasts for thousands of years!
“DNA won’t degrade over time like cassette tapes and CDs, and it won’t become obsolete,” Yaniv Erlich, PhD, Chief Science Officer at MyHeritage, an online genealogy platform located in Israel, and Associate Professor, Columbia University, told Science Mag.
Tape also takes up an enormous amount of physical space compared to DNA. One single gram of DNA can hold 215 petabytes (roughly one zettabyte) of data. Wired puts the storage capacity of DNA into perspective: “Imagine formatting every movie ever made into DNA; it would be smaller than the size of a sugar cube. And it would last for 10,000 years.”
Researchers at the University of Washington claim, “All the movies, images, emails and other digital data from more than 600 basic smartphones (10,000 gigabytes) can be stored in the faint pink smear of DNA at the end of this test tube.” (Photo and caption copyright: Tara Brown/University of Washington.)
Victor Zhirnov, Chief Scientist at Semiconductor Research Corporation says the worries over storage space aren’t simply theoretical. “Today’s technology is already close to the physical limits of scaling,” he told Wired, which stated, “Five years ago humans had produced 4.4 zettabytes of data; that’s set to explode to 160 zettabytes (each year!) by 2025. Current infrastructure can handle only a fraction of the coming data deluge, which is expected to consume all the world’s microchip-grade silicon by 2040.”
MIT Technology Review agrees, stating, “Humanity is creating information at an unprecedented rate—some 16 zettabytes every year. And this rate is increasing. Last year, the research group IDC calculated that we’ll be producing over 160 zettabytes every year by 2025.”
Heavy Investment by Major Players
The whole concept may seem like something out of a science
fiction story, but the fact that businesses are investing real dollars into it
is evidence that DNA for data storage will likely be a reality in the near
future. Currently, there are a couple of barriers, but work is commencing to
overcome them.
First, the cost of synthesizing DNA in a medical laboratory
for the specific purpose of data storage must be cheaper for the solution to
become viable. Second, the sequencing process to read the information must also
become less expensive. And third is the problem of how to extract the data
stored in the DNA.
In a paper published in ASPLOS ‘16, the MR/UW scientists wrote: “Today, neither the performance nor the cost of DNA synthesis and sequencing is viable for data storage purposes. However, they have historically seen exponential improvements. Their cost reductions and throughput improvements have been compared to Moore’s Law in Carlson’s Curves … Important biotechnology applications such as genomics and the development of smart drugs are expected to continue driving these improvements, eventually making data storage a viable application.”
Automation appears to be the final piece of the puzzle. Currently,
too much human labor is necessary for DNA to be used efficiently as data
storage.
“Our ultimate goal is to put a system into production that, to the end user, looks very much like any other cloud storage service—bits are sent to a datacenter and stored there and then they just appear when the customer wants them,” said Microsoft principal researcher Karin Strauss (above), in the Microsoft news release. “To do that, we needed to prove that this is practical from an automation perspective.” Click here to watch a Microsoft Research video on the DNA storage process. (Photo copyright: Microsoft Research/YouTube.)
It may take some time before DNA becomes a viable medium for
data storage. However, savvy pathology laboratory managers should be aware of,
and possibly prepared for, this coming opportunity.
While it’s unlikely the average consumer will see much
difference in how they save and retrieve data, medical laboratories with the
ability to sequence DNA may find themselves very much in demand because of
their expertise in sequencing DNA and interpreting gene sequences.
Genetic data captured by this new technology could lead to a new understanding of how different types of cells exchange information and would be a boon to anatomic pathology research worldwide
What if it were possible to map the interior of cells and view their genetic sequences using chemicals instead of light? Might that spark an entirely new way of studying human physiology? That’s what researchers at the Massachusetts Institute of Technology (MIT) believe. They have developed a new approach to visualizing cells and tissues that could enable the development of entirely new anatomic pathology tests that target a broad range of cancers and diseases.
Scientists at MIT’s Broad Institute and McGovern Institute for Brain Research developed this new technique, which they call DNA Microscopy. They published their findings in Cell, titled, “DNA Microscopy: Optics-free Spatio-genetic Imaging by a Stand-Alone Chemical Reaction.”
Joshua Weinstein, PhD, a postdoctoral associate at the Broad Institute and first author of the study, said in a news release that DNA microscopy “is an entirely new way of visualizing cells that captures both spatial and genetic information simultaneously from a single specimen. It will allow us to see how genetically unique cells—those comprising the immune system, cancer, or the gut for instance—interact with one another and give rise to complex multicellular life.”
The news release goes on to state that the new technology “shows
how biomolecules such as DNA and RNA are organized in cells and tissues,
revealing spatial and molecular information that is not easily accessible
through other microscopy methods. DNA microscopy also does not require
specialized equipment, enabling large numbers of samples to be processed
simultaneously.”
The images above, taken from the MIT study, compares optical imaging of a cell population (left) with an inferred visualization of the same cell population based on the information provided by DNA microscopy (right). Scale bar = 100 μm (100 micrometers). This technology has the potential to be useful for anatomic pathologists at some future date. (Photo and caption copyrights: Joshua Weinstein, PhD, et al/Cell.)
New Way to Visualize Cells
The MIT researchers saw an opportunity for DNA microscopy to
find genomic-level cell information. They claim that DNA microscopy images
cells from the inside and enables the capture of more data than with
traditional light microscopy. Their new technique is a chemical-encoded
approach to mapping cells that derives critical genetic insights from the
organization of the DNA and RNA in cells and tissue.
And that type of genetic information could lead to new precision medicine treatments for chronic disease. New Atlas notes that “ Speeding the development of immunotherapy treatments by identifying the immune cells best suited to target a particular cancer cell is but one of the many potential application for DNA microscopy.”
In their published study, the scientists note that “Despite enormous progress in molecular profiling of cellular constituents, spatially mapping [cells] remains a disjointed and specialized machinery-intensive process, relying on either light microscopy or direct physical registration. Here, we demonstrate DNA microscopy, a distinct imaging modality for scalable, optics-free mapping of relative biomolecule positions.”
How DNA Microscopy Works
The New York Times (NYT) notes that the advantage of DNA microscopy is “that it combines spatial details with scientists’ growing interest in—and ability to measure—precise genomic sequences, much as Google Street View integrates restaurant names and reviews into outlines of city blocks.”
And Singularity Hub notes that “ DNA microscopy, uses only a pipette and some liquid reagents. Rather than monitoring photons, here the team relies on ‘bar codes’ that chemically tag onto biomolecules. Like cell phone towers, the tags amplify, broadcasting their signals outward. An algorithm can then piece together the captured location data and transform those GPS-like digits into rainbow-colored photos. The results are absolutely breathtaking. Cells shine like stars in a nebula, each pseudo-colored according to their genomic profiles.”
“We’ve used DNA in a way that’s mathematically similar to photons in light microscopy,” Weinstein said in the Broad Institute news release. “This allows us to visualize biology as cells see it and not as the human eye does.”
In their study, researchers used DNA microscopy to tag RNA
molecules and map locations of individual human cancer cells. Their method is
“surprisingly simple” New Atlas reported. Here’s how it’s done,
according to the MIT news release:
Small synthetic DNA tags (dubbed “barcodes” by the MIT team) are added to biological samples;
The “tags” latch onto molecules of genetic material in the cells;
The tags are then replicated through a chemical reaction;
The tags combine and create more unique DNA labels;
The scientists use a DNA sequencer to decode and reconstruct the biomolecules;
A computer algorithm decodes the data and converts it to images displaying the biomolecules’ positions within the cells.
The visualization above was created from data gathered by DNA microscopy, which peers inside individual cells. It demonstrates how DNA microscopy enables scientists to identify different cells (colored dots) within a sample—with no prior knowledge of what the sample looks like. (Photo and caption copyright: Joshua Weinstein, PhD, et al./Cell.)
“The first time I saw a DNA microscopy image, it blew me away,” said Aviv Regev, PhD, a biologist at the Broad Institute, a Howard Hughes Medical Institute (HHMI) Investigator, and co-author of the MIT study, in an HHMI news release. “It’s an entirely new category of microscopy. It’s not just a technique; it’s a way of doing things that we haven’t ever considered doing before.”
Precision Medicine Potential
“Every cell has a unique make-up of DNA letters or genotype. By capturing information directly from the molecules being studied, DNA microscopy opens up a new way of connecting genotype to phenotype,” said Feng Zhang, PhD, MIT Neuroscience Professor,
Core Institute Member of the Broad Institute, and
Investigator at the McGovern Institute for Brain Research at MIT, in the HHMI
news release.
In other words, DNA microscopy could someday have applications in precision medicine. The MIT researchers, according to Stat, plan to expand the technology further to include immune cells that target cancer.
The Broad Institute has applied for a patent on DNA
microscopy. Clinical laboratory and anatomic pathology group leaders seeking
novel resources for diagnosis and treatment of cancer may want to follow the MIT
scientists’ progress.
This research could lead to a useful liquid biopsy test that would be a powerful new tool for clinical laboratories and anatomic pathologists
Cancer researchers have long sought the Holy Grail of
diagnostics—a single biomarker that can quickly detect cancer from blood or
biopsied tissue. Now, researchers in Australia may have found that treasure. And
the preliminary diagnostic test they have developed reportedly can return
results in just 10 minutes with 90% accuracy.
In a news release, University of Queensland researchers discussed identifying a “simple signature” that was common to all forms of cancer, but which would stand out among healthy cells. This development will be of interest to both surgical pathologists and clinical laboratory managers. Many researchers looking for cancer markers in blood are using the term “liquid biopsies” to describe assays they hope to develop which would be less invasive than a tissue biopsy.
“This unique nano-scaled DNA signature appeared in every type of breast cancer we examined, and in other forms of cancer including prostate, colorectal, and lymphoma,” said Abu Sina, PhD, Postdoctoral Research Fellow at the Australian Institute for Bioengineering and Nanotechnology (AIBN), University of Queensland (UQ), in the news release.
“We designed a simple test using gold nanoparticles that
instantly change color to determine if the three-dimensional nanostructures of cancer
DNA are present,’ said Matt
Trau, PhD, Professor of Chemistry at the University of Queensland, and
Deputy Director and Co-Founder of UQ’s AIBN, in the news release.
The team’s test is preliminary, and more research is needed before
it will be ready for Australia’s histopathology laboratories (anatomic
pathology labs in the US). Still, UQ’s research is the latest example of how
increased knowledge of DNA is making it possible for researchers to identify
new biomarkers for cancer and other diseases.
“We certainly don’t know yet whether it’s the holy grail for
all cancer diagnostics, but it looks really interesting as an incredibly simple
universal marker of cancer, and as an accessible and inexpensive technology
that doesn’t require complicated lab-based equipment like DNA sequencing,” Trau
added.
The UQ researchers published their study in the journal Nature Communications. In it, they noted that “Epigenetic reprogramming in cancer genomes creates a distinct methylation landscape encompassing clustered methylation at regulatory regions separated by large intergenic tracks of hypomethylated regions. This methylation landscape that we referred to as ‘Methylscape’ is displayed by most cancer types, thus may serve as a universal cancer biomarker.”
While methyl patterning is not new, the UQ researchers say they were the first to note the effects of methyl pattern in a particular solution—water. With the aid of transmission electron microscopy, the scientists saw DNA fragments in three-dimensional structures in the water. But they did not observe the signature in normal tissues in water.
“To date, most research has focused on the biological consequences of DNA Methylscape changes, whereas its impact on DNA physicochemical properties remains unexplored,” UQ scientists Matt Trau, PhD (left), Abu Sina, PhD (center), and Laura Carrascosa (right), wrote in their study. “We exploit these Methylscape differences to develop simple, highly sensitive, and selective electrochemical or colorimetric one-step assays for the detection of cancer.” (Photo copyright: University of Queensland.)
Their test averaged 90% accuracy during the testing of 200
human cancer samples. Furthermore, the researchers found the DNA structure to
be the same in breast, prostate, and bowel cancers, as well as lymphomas, noted
The Conversation.
“We find that DNA polymeric
behavior is strongly affected by differential patterning of methylcytosine
leading to fundamental differences in DNA solvation and DNA-gold affinity
between cancerous and normal genomes,” the researchers wrote in NatureCommunications.“We exploit
these methylscape differences to develop simple, highly sensitive, and
selective electrochemical or one-step assays for detection of cancer.”
Next Steps for the
“Gold Test”
“This approach represents an exciting step forward in
detecting tumor DNA in blood samples and opens up the possibility of a generalized
blood-based test to detect cancer, Ged Brady, PhD, Cancer Research UK
Manchester Institute, told The
Oxford Scientist. “Further clinical studies are required to evaluate
the full clinic potential of the method.”
Researchers said the next step is a larger clinical study to
explore just how fast cancer can be detected. They expressed interest in
finding different cancers in body fluids and at various stages. Another opportunity
they envision is to use the cancer assay with a mobile device.
DiCarlo told USA Today
that such a mobile test could be helpful to clinicians needing fast answers for
people in rural areas. However, he’s also concerned about false positives. “You
don’t expect all tumors to have the same methylation pattern because there’s so
many different ways that cancer can develop,” he told USA Today. “There
are some pieces that don’t exactly align logically.”
The UQ researchers have produced an intriguing study that differs
from other liquid biopsy papers covered by Dark Daily. While their test may need to be used in combination with other
diagnostic tests—MRI, mammography, etc.—it has the potential to one day be used
by clinical laboratories to quickly reveal diverse types of cancers.
Diagnostic medical laboratories may sequence DNA genetic tests correctly, but there are issues with how companies analyze the information
In 2017, some 12 million people paid to spit in a tube and have their genetic data analyzed, according to Technology Review. Many companies offer this type of DNA testing, and each of them works with one or more clinical laboratories to get the actual sequencing performed. For example, Ancestry.com, one of the largest direct-to-consumer genetic data testing companies, works with both Quest Diagnostics and Illumina.
In the case of Quest Diagnostics, the clinical laboratory company does the actual sequencing for Ancestry. But the analysis of the genetic data for an individual and its interpretation is performed by Ancestry’s team.
There are critics of the booming direct-to-consumer genetic testing business, but it’s not due to the quality of the sequencing. Rather, critics cite other issues, such as:
Privacy concerns;
How the physical samples are stored and used;
Who owns the data; and,
That this branch of genetics is an area of emerging study and not clearly understood.
What Does All That Genetic Data Mean?
The consumer DNA testing market was worth $359 million dollars in 2017 and is projected to grow to $928 million by 2023, according to a report from Research and Markets. Those numbers represent a lot of spit, and an enormous amount of personal health information. As of now, some one in every 25 adults in the US has access to their genetic data. But, what does all that data mean?
The answer depends, in large part, on who you ask. Many reporters, scientists, and others have taken multiple DNA tests from different companies and received entirely different results. In some cases, the sequencing from one sample submitted to different companies for analysis have rendered dramatically different results.
“There is a wild-west aspect to all of this,” Erin Murphy, a New York University law professor and genetics specialist who focuses on privacy implications, told McClatchy. “It just takes one person in a family to reveal the genetic information of everyone in the family,” she notes. (Photo copyright: New York University.)
It’s All About the Database
Although some people purchase kits from multiple companies, the majority of people take just one test. Each person who buys genetic analysis from Ancestry, for example, consents to having his/her data become part of Ancestry’s enormous database, which is used to perform the analyses that people pay for. There are some interesting implications to how these databases are built.
First, they are primarily made up of paying customers, which means that the vast majority of genetic datasets in Ancestry’s database come from people who have enough disposable income to purchase the kit and analysis. It may not seem like an important detail, but it shows that the comparison population is not the same as the general population.
Second, because the analyses compare the sample DNA to DNA already in the database, it matters how many people from any given area have taken the test and are in the database. An article in Gizmodo describes one family’s experience with DNA testing and some of the pitfalls. The author quotes a representative from the company 23andMe as saying, “Different companies have different reference data sets and different algorithms, hence the variance in results. Middle Eastern reference populations [for example] are not as well represented as European, an industry-wide challenge.”
The same is true for any population where not many members have taken the test for a particular company. In an interview with NPR about trying to find information about her ancestry, journalist Alex Wagner described a similar problem, saying, “There are not a lot of Burmese people taking DNA tests … and so, the results that were returned were kind of nebulous.”
Wagner’s mother and grandmother both immigrated to the US from Burma in 1965, and when Wagner began investigating her ancestry, she, both of her parents, and her grandmother, all took tests from three different direct-to-consumer DNA testing companies. To Wagner’s surprise, her mother and grandmother both had results that showed they were Mongolian, but none of the results indicated Burmese heritage. In the interview she says that one of the biggest things she learned through doing all these tests was that “a lot of these DNA test companies [are] commercial enterprises. So, they basically purchase or acquire DNA samples on market-demand.”
As it turns out, there aren’t many Burmese people taking DNA tests, so there’s not much reason for the testing companies to pursue having a robust Burmese or even Southeast Asian database of DNA.
Who Owns Your Genetic Data?
As is often the case when it comes to technological advances, existing law hasn’t quite caught up with the market for ancestry DNA testing. There are some important unanswered questions, such as who owns the data that results from a DNA analysis?
An investigation conducted by the news organization McClatchy found that Ancestry does allow customers to request their DNA information be deleted from the company’s database, and that they can request their physical sample be destroyed as well. The author writes, “But it is a two-step process, and customers must read deep into the company’s privacy statement to learn how to do it. Requests for DNA data elimination can be made online, but the company asks customers to call its support center to request destruction of their biological sample.”
Another concern is hacking or theft. Ancestry and similar companies take steps to protect customers’ information, such as using barcodes rather than names and encryption when samples are sent to labs. Nevertheless, there was an incident in 2017 in which hackers infiltrated a website owned by Ancestry called RootsWeb. “The RootsWeb situation was certainly unfortunate,” Eric Heath, Ancestry’s Chief Privacy Officer, told McClatchy. He added that RootsWeb was a “completely separate system” from the Ancestry database that includes DNA information.
What We Don’t Know
The biggest pitfall for consumers may be that geneticists don’t know very much about DNA analysis. Adam Rutherford, PhD, is a British geneticist who interviewed for the Gizmodo story. He said that the real problem with companies like Ancestry is that people have a basic, fundamental misunderstanding of what can be learned from a DNA test.
“They’re not telling you where your DNA comes from in the past. They’re telling you where on Earth your DNA is from today,” Rutherford told Gizmodo.
Science evolves, of course, and genetic testing has much evolving to do. The author of the Gizmodo piece writes, “It’s not that the science is bad. It’s that it’s inherently imperfect.” There aren’t any best-practices for analyzing DNA data yet, and companies like Ancestry aren’t doing much to make sure their customers understand that fact.
Nevertheless, issues surrounding genetic testing, the resulting data, and its storage, interpretation, and protection, continue to impact clinical laboratories and anatomic pathology groups.
