Findings could lead to new therapies and clinical laboratory biomarkers for detecting and defeating antibiotic-resistant bacteria
Once again, new research shows that human gut bacteria (microbiota) may be useful in fighting antibiotic-resistant bacterial infections. The study findings could provide new therapeutics and clinical laboratory biomarkers for diagnosing and treating severe gastrointestinal disorders.
Antibiotic-resistant bacterial infections often appear in patients with chronic intestinal conditions and in those with long-term antibiotic use. Enterobacteriaceae is a large family of gram-negative bacteria that includes more than 30 genera and over 100 species.
“Despite two decades of microbiome research, we are just beginning to understand how to define health-promoting features of the gut microbiome,” said Marie-Madlen Pust, PhD, a computational postdoctoral researcher at the Broad Institute and co-first author of the paper, in the news release.
“Part of the challenge is that each person’s microbiome is unique. This collaborative effort allowed us to functionally characterize the different mechanisms of action these bacteria use to reduce pathogen load and gut inflammation,” she added.
The researchers identified a way to treat patients infected by antibiotic-resistant strains of bacteria that does not involve antibiotics. Should further research validate these early findings, this could be a viable approach to treating patients with this condition.
“Microbiome studies can often consist of analyzing collections of genetic sequences, without understanding what each gene does or why certain microbes are beneficial,” said Ramnik Xavier, MD (above), director of Broad Institute’s immunology program, co-director of the infectious disease and microbiome program, and co-senior author on the study, in a news release. “Trying to uncover that function is the next frontier, and this is a nice first step towards figuring out how microbial metabolites influence health and inflammation.” Clinical laboratories that test for intestinal conditions caused by antibiotic resistance will want to follow the Broad Institute’s research. (Photo copyright: Broad Institute.)
Suppressing Growth of Antibiotic-resistant Bacteria
To perform their research, the scientists isolated about 40 strains of bacteria from the stools of five healthy fecal donors. They then used those stool samples in fecal microbiota transplants to treat mice that had been infected with either Escherichia coli (E. coli) or Klebsiella, both forms of Enterobacteriaceae. The scientists tested different combinations of the 40 strains and identified 18 that suppressed the growth of Enterobacteriaceae.
“Antibiotic-resistant Enterobacteriaceae such as E. coli and Klebsiella bacteria are common in hospitals, where they can proliferate in the gut of patients and cause dangerous systemic infections that are difficult to treat. Some research suggests that Enterobacteriaceae also perpetuates inflammation in the intestine and infection by other microbes,” the Broad Institute news release notes.
The researchers discovered that Klebsiella changed the gene expression in carbohydrate uptake and metabolism in the Klebsiella-infected mice that were treated with the 18 beneficial strains. The gene expression included the downregulating of gluconate kinase and transporter genes, which revealed there is increased competition among gut bacteria for nutrients.
When combined, these 18 strains alleviated inflammation in the guts of the treated mice by depriving the harmful gut bacteria of carbohydrates. This non-antibiotic approach also prevented harmful bacteria from colonizing in the gut.
“In partnership with the Broad’s Metabolomics Platform, led by senior director and study co-author Clary Clish, PhD, they analyzed samples from pediatric patients with ulcerative colitis, looking for the presence of alternate gluconate pathway genes of gut microbes and fecal gluconate levels. They found higher levels of gluconate linked to more gluconate-consuming Enterobacteriaceae in samples from pediatric patients with ongoing inflammation, indicated by high levels of the protein calprotectin,” the study authors wrote in Nature.
“Together, the findings suggest that Enterobacteriaceae processes gluconate as a key nutrient and contributes to inflammation in patients. But when a gut microbiome includes the 18 helpful strains, they likely compete with Enterobacteriaceae for gluconate and other nutrient sources, limiting the proliferation of the harmful bacteria,” the scientists concluded.
Promising New Bacterial Therapies
This research could ultimately lead to the development of fecal microbiota transplants for individuals to eradicate antibiotic-resistant bacteria in a more objective and specific manner, with fewer side effects than current treatments.
“Harnessing these activities in the form of live bacterial therapies may represent a promising solution to combat the growing threat of proinflammatory, antimicrobial-resistant Enterobacteriaceae infection,” the scientists wrote in Nature.
According to the news release, they plan to continue research to “uncover the identity and function of unknown metabolites that contribute to gut health and inflammation.” The team hopes to discover how different bacteria compete with each other, and to develop microbial therapeutics that improve gut microbiome and curb bacterial infections.
More studies are needed to prove the efficacy of this type of fecal bacterial treatment. However, this research demonstrates how using nano processes enabled by new technologies to identify the actual work of proteins, RNA, and DNA in the body cheaply, faster, and with greater precision, will open doors to both therapeutic and diagnostic clinical laboratory biomarkers.
Results of an earlier study in which locks of Beethoven’s hair underwent genetic analysis showed the composer ‘had a predisposition for liver disease and became infected with hepatitis B’
Here is an example of modern technologies being used with “historical biospecimens” to solve long-standing mysteries or questions about the illnesses of famous historical figures. Clinical laboratory scientists at the Mayo Clinic have used modern-day chemical analysis techniques to answer a 200-year-old question: What caused Ludwig van Beethoven’s deafness and other health problems?
“Such lead levels are commonly associated with gastrointestinal and renal ailments and decreased hearing but are not considered high enough to be the sole cause of death,” the authors wrote.
Beethoven’s death at age 56 has been attributed to kidney and liver disease, CNN reported. Even if the lead concentrations were not the sole cause, they would nevertheless be regarded as lead poisoning, lead study author Nader Rifai, PhD, told CNN.
“If you walk into any emergency room in the United States with these levels, you will be admitted immediately and you will undergo chelation therapy,” he said.
“It is believed that Beethoven died from liver and kidney disease at age 56. But the process of understanding what caused his many health problems has been a much more complicated puzzle, one that even Beethoven himself hoped doctors could eventually solve,” CNN reported, adding, “The composer expressed his wish that his ailments be studied and shared so ‘as far as possible at least the world will be reconciled to me after my death.’” Mayo clinical laboratory scientists are using chemical analysis on authenticated locks of Beethoven’s hair to do just that. (Photo copyright: Joseph Karl Stieler/Public Domain.)
Mass Spectrometry Analysis
Mayo Clinic’s metals laboratory, led by chemist Paul Jannetto, PhD, an associate professor in the Department of Laboratory Medicine and Pathology and Laboratory Director at the Mayo Clinic, performed the analysis on two authenticated locks of Beethoven’s hair, using inductively coupled plasma mass spectrometers.
The researchers found that one lock had 258 micrograms of lead/gram and the other had 380 micrograms. Normally they would expect to find less than four micrograms.
“These are the highest values in hair I’ve ever seen,” Jannetto told The New York Times. “We get samples from around the world and these values are an order of magnitude higher.”
The researchers also found that the composer’s hair had four times the normal level of mercury and 13 times the normal amount of arsenic.
Rifai and other researchers noted that Beethoven drank large amounts of plumbed wine, and at the time it was common to sweeten wine with lead acetate, CNN reported.
The composer also could have been exposed to lead in glassware. He likely absorbed high levels of arsenic and mercury by eating fish caught from the Danube River in Vienna.
David Eaton, PhD, a toxicologist, pharmacologist, and Professor Emeritus, Department of Environmental and Occupational Health Sciences at the University of Washington, told The New York Times that high levels of lead could have impaired Beethoven’s hearing through their effect on the nervous system. Additionally, he said the composer’s gastrointestinal ailments “are completely consistent with lead poisoning.”
Rifai told CNN that he’d like to study locks of hair from other 19th century Vienna residents to see how their lead levels compared with Beethoven’s.
Beethoven’s Genome and Genetic Predisposition for Liver Disease
Additional research published in May built on an earlier genomic analysis of Beethoven’s hair, which appeared in March 2023 in the journal Current Biology.
The international team included geneticists, archeologists, and immunologists who analyzed eight locks of hair attributed to the composer. They determined that five were authentic. One, known as the Stumpff Lock, appeared to be the best preserved. They used this lock to sequence Beethoven’s DNA.
“Although we could not identify a genetic explanation for Beethoven’s hearing disorder or gastrointestinal problems, we found that Beethoven had a genetic predisposition for liver disease,” the authors wrote. “Metagenomic analyses revealed furthermore that Beethoven had a hepatitis B infection during at least the months prior to his death. Together with the genetic predisposition and his broadly accepted alcohol consumption, these present plausible explanations for Beethoven’s severe liver disease, which culminated in his death.”
One surprising discovery was the likelihood of an extramarital affair on the composer’s father’s side, CNN reported. The researchers learned this in part by comparing his genetic profile with those of living relatives.
“Through the combination of DNA data and archival documents, we were able to observe a discrepancy between Ludwig van Beethoven’s legal and biological genealogy,” study coauthor Maarten Larmuseau, PhD, told CNN. Larmuseau is assistant professor, Faculty of Medicine, and head of the Laboratory of Human Genetic Genealogy at KU Leuven in Belgium.
The Mayo Clinic team used two locks authenticated in the 2023 study—the Bermann Lock and Halm-Thayer Lock—to perform their chemical analysis, CNN reported.
Beethoven’s Wishes
The earlier study noted that Beethoven wanted his health problems to be made public. In 1802, he wrote a document known as the Heiligenstadt Testament in which he asked that his physician, surgeon/ophthalmologist Johann Adam Schmidt, MD, discuss his disease after he died.
“For almost two years I have ceased to attend any social functions, just because I find it impossible to say to people: I am deaf,” Beethoven wrote at age 30, The New York Times reported. “If I had any other profession, I might be able to cope with my infirmity, but in my profession, it is a terrible handicap. And if my enemies, of whom I have a fair number, were to hear about it, what would they say?”
The authors of the Current Biology paper wrote, “Genomic sequence data from authenticated locks of Beethoven’s hair provide Beethoven studies with a novel primary source, already revealing several significant findings relating to Beethoven’s health and genealogy, including substantial heritable risk for liver disease, infection with HBV [Hepatitis B], and EPP [extra pair paternity]. This dataset additionally permits numerous future lines of scientific inquiry.
“The further development of bioinformatics methods for risk stratification and continued progress in medical genetic research will allow more precise assessments both for Beethoven’s disease risk and for the genetic inference of additional phenotypes of interest.
“This study illustrates the contribution and further potential of genomic data as a novel primary source in historical biography,” the scientists concluded.
The work of the clinical laboratory professionals at Mayo Clinic also demonstrates how advances in various diagnostic technologies can enable pathologists and lab scientists to participate in solving long-standing health questions about historical figures, especially if their hair or other types of specimens survived and can be used in the analysis.
