PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Lung infection may be less transmissible than thought

Study calls into question pathogen’s ability to spread from person to person

2023-05-30
(Press-News.org) A little-known bacterium — a distant cousin of the microbes that cause tuberculosis and leprosy — is emerging as a public health threat capable of causing severe lung infections among vulnerable populations, those with compromised immunity or reduced lung function.

Recent research found that various strains of the bacterium, Mycobacterium abscessus, were genetically similar, stoking fears that it was spreading from person to person.

But a new study by Harvard Medical School researchers published May 22 in PNAS, calls those findings into question, offering an alternative explanation behind the genetic similarity of clinical clusters. This suggests that the pathogen may not be that prone to person-to-person transmission after all. 

“Our findings make a strong case for a different explanation behind the observed genetic similarities across strains,” said study senior author Maha Farhat, the Gilbert S. Omenn Associate Professor of Biomedical Informatics at HMS and a pulmonary disease expert at Massachusetts General Hospital. Farhat conducted the work in collaboration with Eric Rubin’s lab at the Harvard T.H. Chan School of Public Health.

The results, Farhat added, argue against direct person-to-person transmission in clinical settings and instead point to M. abscessus infections being acquired from the home or other environmental exposures.

In addition to having implications for the precautions that hospitals take to prevent outbreaks, it’s an important new clue into the behavior of a relatively unknown pathogen that poses serious risks for vulnerable populations.

The research not only contributes to the understanding of M. abscessus transmission, but also suggests scientists should be cautious about assuming human transmission when they see genetic similarities in pathogens more generally, said study first author Nicoletta Commins, who conducted the research as a doctoral candidate at HMS and is now a postdoctoral fellow at the Broad Institute. 

“Our results certainly do not refute the possibility of person-to-person transmission of Mycobacterium abscessus in some cases, and more research is needed to inform best clinical practice for vulnerable patients,” she said. “However, our work supports a model in which person-to-person transmission may not be as common as it is sometimes suggested to be.”

M. abscessus is a hardy microbe highly resistant to antibiotics and can infect the lungs of immunocompromised people. While it doesn’t pose a threat to most healthy individuals, it can cause severe infection in those with suppressed immunity or people with compromised lung function such as patients with cystic fibrosis, a genetic condition marked by recurrent lung infections and lung scarring. Notably, patients with CF who become infected with this organism become ineligible for lifesaving lung transplants.

The earlier study that sounded the alarm about person-to-person transmission was based on genetic sequencing of M. abscessus samples obtained from cystic fibrosis patients at clinics in the United States, Australia, and Europe, including the United Kingdom. Researchers found few genetic mutations across the samples — a possible sign that the pathogen was spreading directly between humans. 

For many pathogens such as TB, for example, recent person-to-person transmission leads to only a few or no mutations between any pair of samples simply because the pathogen does not have much time to acquire genetic mutations, Farhat explained.

“Understandably, observing the genetic similarity between M. abscessus samples caused a great deal of anxiety and fear around how these organisms could be transmitting,” she said.

Clinicians, especially in clinics that treat cystic fibrosis patients, began taking extra precautions to avert transmission. However, follow-up investigations failed to find supporting evidence that human-to-human transmission was happening, raising questions about other possible explanations for the genetic similarities across samples.

Farhat’s team set out to investigate a hypothesis that the samples appeared genetically similar because the pathogen was evolving at a very slow rate.

“We thought, yeah, you observed a small number of mutations, but we don’t know how quickly these mutations are acquired, she explained. “It may be slower than we think, and links between samples that appear recent may not be.’” 

The scientists first used a large dataset of M. abscessus genomes to create a “tree of life,” a kind of genetic family tree for the bacterium. 

They looked at branches of the tree with clusters of genetically similar strains, then tried to calculate their evolutionary rate. They found that these genetically similar clusters were evolving around 10 times more slowly than typical M. abscessus strains.

Next, they used computer modeling to determine whether the genetic similarities could be explained by the relatively small population size of these bacteria. But even when they simulated extreme population sizes, the result didn’t change. This was an indicator that the high genetic similarity is best explained by a slower evolutionary rate.

Finally, researchers conducted experiments to see how fast different strains of M. abscessus evolved to develop resistance when exposed to antibiotics in the lab. They found that the genetically similar strains evolved much more slowly than other strains.

“These are three separate lines of evidence supporting this idea that these clustered isolates of Mycobacterium abscessus are evolving at a slower rate,” Farhat said. 

In addition to reducing concern about person-to-person transmission, the findings provide new insight into a poorly understood pathogen. 

In particular, the results offer clues about how a bug found primarily in the environment adapts and changes after it enters the human body — information that could help scientists eventually understand how to prevent and treat infections.

Farhat is now planning follow-up studies that would compare bacteria in the environment with samples taken from patients, to better understand why certain patients become infected. 

Authorship, funding, disclosures

Additional authors included Mark R. Sullivan, Kerry McGowen 

Evan Koch, and Eric Rubin. The work was partly supported by the Damon Runyon Cancer Research Foundation, DRG-2415-20, with additional support from the Orchestra High Performance Compute Cluster at Harvard Medical School, funded by the NIH NCRR 1S10RR028832-01.

END


ELSE PRESS RELEASES FROM THIS DATE:

Experimental decoy protects against SARS-CoV-2 infection

2023-05-30
An experimental “decoy” provided long-term protection from infection by the pandemic virus in mice, a new study finds. Led by researchers at NYU Grossman School of Medicine, the work is based on how the virus that causes COVID-19, SARS-CoV-2, uses its spike protein to attach to a protein on the surface of the cells that line human lungs. Once attached to this cell surface protein, called angiotensin converting enzyme 2 (ACE2), the virus spike pulls the cell close, enabling the virus to enter the cell and hijack its machinery to make viral copies.  Earlier in the pandemic, pharmaceutical ...

Light conveyed by the signal transmitting molecule sucrose controls growth of plant roots

2023-05-30
Plant growth is driven by light and supplied with energy through photosynthesis by green leaves. It is the same for roots that grow in the dark – they receive the products of photosynthesis, in particular sucrose, i.e. sugar, via the central transportation pathways of phloem. Dr. Stefan Kircher and Prof. Dr. Peter Schopfer from the University of Freiburg’s Faculty of Biology have now shown in experiments using the model plant Arabidopsis thaliana (thale cress) that the sucrose not only guarantees the supply of carbohydrates to the roots, it also acts as a signal transmitter for ...

Mitigating climate change through restoration of coastal ecosystems

2023-05-30
One of the primary drivers of climate change is excess greenhouse gases like carbon dioxide in the atmosphere. Mitigating climate change in the coming century will require both decarbonization — electrifying the power grid or reducing fossil fuel-guzzling transportation —  and removing already existing carbon dioxide from the atmosphere, a process called carbon dioxide removal. Researchers at the Georgia Institute of Technology and Yale University are proposing a novel pathway through which coastal ecosystem restoration can permanently capture carbon dioxide from the atmosphere. Seagrass and mangroves — known as blue carbon ecosystems — naturally capture ...

Flexible nanoelectrodes can provide fine-grained brain stimulation

Flexible nanoelectrodes can provide fine-grained brain stimulation
2023-05-30
HOUSTON – (May 30, 2023) – Conventional implantable medical devices designed for brain stimulation are often too rigid and bulky for what is one of the body’s softest and most delicate tissues. To address the problem, Rice University engineers have developed minimally invasive, ultraflexible nanoelectrodes that could serve as an implanted platform for administering long-term, high-resolution stimulation therapy. According to a study published in Cell Reports, the tiny implantable devices formed stable, long-lasting and seamless tissue-electrode ...

Teens with irregular sleep patterns have higher risk of school problems

2023-05-30
DARIEN, IL – A new study to be presented at SLEEP 2023 found that teens with greater variability in their sleep patterns have a higher risk for school-related problems. Results show that the teens with greater night-to-night variability in the time they fell asleep were 42% more likely to have been suspended or expelled in the past two years, 29% more likely to have received a D or F in any course, and 26% more likely to have ever failed a course. The likelihood of suspension or expulsion was also 31% higher in teens with greater variability in sleep duration. “Variability in sleep duration and later sleep ...

Genetic risk information may help people avoid alcohol addiction

2023-05-30
Today’s substance use prevention efforts ignore individual genetic risk, but Rutgers research suggests DNA test results may eventually enhance prevention and treatment and improve outcomes. Investigators recruited 325 college students, provided them with varying levels of information about alcohol use disorder and how genetics affect addiction risk and asked them how they would react to learning they had high, medium and low genetic tendencies toward alcoholism. The results provided two significant supports for eventually using real genetic risk scores in actual addiction prevention efforts. First, participants understood what those scores indicated; they recognized that higher ...

Advances in technology are driving popularity of EVs

2023-05-30
Transportation accounts for roughly one-third of U.S. greenhouse gas emissions, and adoption of electric vehicles are seen by many experts in government and the private sector as a vital tool in efforts to reduce carbon emissions. Roughly a decade ago, EVs accounted for a tiny fraction of overall car sales. As of March 2023, they make up 7% of new sales “What changed between then and now?” asks Kenneth Gillingham, professor of environmental and energy economics at the Yale School of the Environment. ...

Newborns with higher hair cortisol levels take longer to fall asleep

2023-05-30
DARIEN, IL – Cortisol levels in late pregnancy can predict the sleep of infants, according to a new study to be presented at the SLEEP 2023 annual meeting.  Results show that newborns with higher levels of cortisol in their hair samples took longer to fall asleep at 7 months of age. Neonatal hair cortisol is a measure of fetal cortisol in the last trimester of pregnancy.  “Although increases in cortisol across pregnancy are normal and important for preparing the fetus for birth, our findings ...

That’s not nuts: Almond milk yogurt packs an overall greater nutritional punch than dairy-based

2023-05-30
May 30, 2023 That’s Not Nuts: Almond Milk Yogurt Packs an Overall Greater  Nutritional Punch than Dairy-Based UMass Amherst food science major completes comparison of 612 plant-based and dairy yogurts AMHERST, Mass. – In a nutritional comparison of plant-based and dairy yogurts, almond milk yogurt came out on top, according to research led by a University of Massachusetts Amherst food science major. “Plant-based yogurts overall have less total sugar, less sodium and more fiber than dairy, but they have less protein, calcium and potassium than dairy yogurt,” ...

Using AI to create better, more potent medicines

2023-05-30
COLUMBUS, Ohio – While it can take years for the pharmaceutical industry to create medicines capable of treating or curing human disease, a new study suggests that using generative artificial intelligence could vastly accelerate the drug-development process.  Today, most drug discovery is carried out by human chemists who rely on their knowledge and experience to select and synthesize the right molecules needed to become the safe and efficient medicines we depend on. To identify the synthesis paths, scientists often employ a technique called retrosynthesis – a method for creating potential drugs by working backward from the wanted molecules and searching for chemical reactions ...

LAST 30 PRESS RELEASES:

Drug helps reprogram macrophage immune cells, suppress prostate and bladder tumor growth

Green infrastructure plans need to consider historical racial inequalities, say researchers

ENDO 2024 press conferences to highlight male birth control, anti-obesity medications

Highly sensitive fiber optic gyroscope senses rotational ground motion around active volcano

Research reveals endurance exercise training impacts biological molecules

Does managing oxidative stress hold the key to effectively treating Alzheimer’s disease

Warming climate intensifies flash droughts worldwide

US public health preparedness and response to highly pathogenic avian influenza A(H5N1) viruses

DRI to host AWE+ wildfire summit

MD Anderson Research Highlights for May 21, 2024

Polymer research aims to expand possibilities in sensor technology

New therapeutic avenues in bone repair

Socioeconomic status transition throughout life and risk of dementia

Climbing the social ladder slows dementia, Japanese study reveals

Researchers discover hidden step in dinosaur feather evolution

Studies reveal cell-by-cell changes caused when pig hearts and kidneys are transplanted into humans

SRI earns FDA Orphan Drug Designation for pancreatic cancer

A new gene-editing system tackles complex diseases

Tracking down toxic metals from tobacco smoke

Clarifying the cellular mechanisms underlying periodontitis with an improved animal model

Age, race impact AI performance on digital mammograms

SwRI leads courses at 2024 Society of Tribologists & Lubrication Engineers Annual Meeting

Hope for a cure for visceral leishmaniasis, an often fatal infectious disease

How AI helps programming a quantum computer

New research reveals that prehistoric seafloor pockmarks off the California coast are maintained by powerful sediment flows

AI can help improve ER admission decisions, Mount Sinai study finds

Matcha mouthwash inhibits bacteria that causes periodontitis

Oncology events in Poland solidify collaboration with NCCN

City of Hope awarded $5.4 million CIRM grant to create a stem cell laboratory and expand access to state-of-the-art disease models and technology among a diverse scientific community

Meeting preview: Hot topics at NUTRITION 2024

[Press-News.org] Lung infection may be less transmissible than thought
Study calls into question pathogen’s ability to spread from person to person