Tag Archives: Antibiotic

New tool shows early promise to help reduce the spread of antimicrobial resistance

A new tool which could help reduce the spread of antimicrobial resistance is showing early promise, through exploiting a bacterial immune system as a gene editing tool.

Antimicrobial resistance is a major global threat, with nearly five million deaths annually resulting from antibiotics failing to treat infection, according to the World Health Organisation.

Bacteria often develop resistance when resistant genes are transported between hosts. One way that this occurs is via plasmids – circular strands of DNA, which can spread easily between bacteria, and swiftly replicate. This can occur in our bodies, and in environmental settings, such as waterways.

The Exeter team harnessed the CRISPR-Cas gene editing system, which can target specific sequences of DNA, and cuts through them when they are encountered. The researchers engineered a plasmid which can specifically target the resistance gene for Gentamicin – a commonly used antibiotic.

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In laboratory experiments, the new research, published in Microbiology, found that the plasmid protected its host cell from developing resistance. Furthermore, researchers found that the plasmid effectively targeted antimicrobial-resistant genes in hosts to which it transferred, reversing their resistance.

Antimicrobial resistance threatens to outstrip covid in terms of the number of global deaths. We urgently need new ways to stop resistance spreading between hosts. Our technology is showing early promise to eliminate resistance in a wide range of different bacteria. Our next step is to conduct experiments in more complex microbial communities. We hope one day it could be a way to reduce the spread of antimicrobial resistance in environments such as sewage treatment plants, which we know are breeding grounds for resistance.”

David Walker-Sünderhauf, Lead Author, University of Exeter

The research is supported by GW4, the Medical Research Council, the Lister Institute, and JPI-AMR.

Source:
Journal reference:

Walker-Sünderhauf, D., et al. (2023) Removal of AMR plasmids using a mobile, broad host-range, CRISPR-Cas9 delivery tool. Microbiology. doi.org/10.1099/mic.0.001334.

Transforming antibiotic resistance testing: a novel, rapid and affordable technique

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Thought LeadersDr. Sandor KasasResearch LeadEcole Polytechnique Fédérale de Lausanne

News Medical speaks with Dr. Sandor Kasas, a lead researcher at Ecole Polytechnique Fédérale de Lausanne in Switzerland. Here we discuss his recent development of a novel and highly efficient method for rapid antibiotic susceptibility testing using optical microscopy.

The new technique, known as Optical Nanomotion Detection (ONMD), is an extremely rapid, label-free, and single-cell sensitive method to test for antibiotic sensitivity. ONMD requires only a traditional optical microscope equipped with a camera or mobile phone. The simplicity and efficiency of the technique could prove to be a game changer in the field of antibiotic resistance.

Please can you introduce yourself, tell us about your career background, and what inspired your career in biology and medicine?

I graduated in medicine but never practiced in hospitals or medical centers. After my studies, I started working as an assistant in histology at the University of Fribourg in Switzerland. My first research projects included image processing, scanning tunneling, and atomic force microscopy.

Later, and for most of the rest of my scientific carrier, I focused primarily on the biological applications of AFM. For the past ten years, my research interest is about nanomotion, i.e., the study of oscillations at a nanometric scale of living organisms.

Image Credit: dominikazara/Shutterstock.comImage Credit: dominikazara/Shutterstock.com

You started working on biological applications of the atomic force microscope (AFM) in 1992. From your perspective, how has the antibiotic resistance landscape changed over the last two decades? What role has the advancement in technology played in furthering our understanding?

In the early ’90s, the AFM was mainly used for imaging. Later, AFM microscopists noticed that the instrument could also be used to explore the mechanical properties of living organisms. More recently, many “exotic” applications of the AFM have emerged, such as its use to weigh single cells or study their oscillations at the nanometric scale. In the 1990s, antibiotic resistance was not as serious a problem as today, but several teams were already using AFM to assess the effects of antibiotics on bacterial morphology.

The first investigations were limited to structural changes, but later, as the fields of application of AFM expanded, the instrument made it possible to monitor the mechanical properties of the bacterial cell wall upon exposure to antibiotics. In the 2010s, with G. Longo and G. Dietler, we demonstrated that AFM could also track nanoscale oscillations of living organisms. The very first application we had in mind was using the instrument to perform rapid antibiotic susceptibility testing.

We have therefore developed devices based on dedicated AFM technology to perform fast AST (i.e., in 2-4h). AFM-based nanomotion detection instruments are already implemented in medical centers in Switzerland, Spain, and Austria. However, this type of device has some drawbacks, including the need to fix the organism of interest on a cantilever. To overcome this limitation, we have developed with R. Willaert a nanomotion detector based on an optical microscope.

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Your most recent research has led to the development of a novel and highly efficient technique for rapid antibiotic susceptibility testing using optical microscopy. Please could you tell us why the development of rapid, affordable, and efficient testing methods is so important in the world of antimicrobial resistance?

Rapid antibiotic susceptibility testing could reduce the use of broad-spectrum antibiotics. Traditional ASTs based on replication rate require 24 hours (but up to 1 month in the case of tuberculosis) to identify the most effective antibiotic. Doctors prescribe broad-spectrum antibiotics between the patient’s admission to a medical center and the results of the AST.

These drugs quickly improve patients’ conditions but, unfortunately, promote resistance. A rapid AST that could identify the most suitable antibiotic within 2-4 hours would eliminate broad-spectrum antibiotics and increase treatment efficiency and reduce the development of resistant bacterial strains. Since bacterial resistance is a global problem, rapid ASTs should also be implemented in developing countries. Therefore, affordable and simple-to-use tests are needed.

Image Credit: Fahroni/Shutterstock.comImage Credit: Fahroni/Shutterstock.com

Were there any limitations and obstacles you faced in the research process? If so, how did you overcome them?

Antibiotic sensitivity detection with ONMD is very similar to the AFM-based technique. As long as the bacterium is alive, it oscillates; if the antibiotic is effective, it kills the micro-organism, and its oscillations stop. The first limitation we faced when developing the ONMD was our microscopes’ depth of field of view. To prevent the bacteria from leaving the focal plane of the optical microscope during the measurement, we had to constrain the microbes into microfluidic channels a few micrometers high.

Microfabrication of such devices is relatively straightforward in an academic environment, but we were looking for simpler solutions. One option for constructing such a device is to use 10-micron double-sided rubber tape. It allows you to “build” a microfluidic chamber in 5 minutes with two glass coverslips and a puncher.

Another challenge was nanoscale motion detection. For this purpose, we used freely available cross-correlation algorithms that achieve sub-pixel resolution. (i.e., a few nanometers). We first developed the ONMD for larger organisms, such as yeast cells, and expanded the method to bacteria. This further development took us around two years.

You worked alongside Dr. Ronnie Willaert, a professor of structural biology at Vrije Universiteit Brussel, on developing this new rapid AST technique. How did your areas of expertise and research backgrounds complement each other in developing ONMD?

R. Willaert is an expert in yeast microbiology and microfluidics, while our team in Lausanne is primarily involved in AFM-based nanomotion detection and applying AFM to clinically relevant problems. The two teams were supported by a joint grant from the Swiss National Science Foundation and the Research Foundation Flanders (FWO) which enabled the development of the method.

The field of antimicrobial resistance requires a high level of international collaboration, with everyone working together to achieve a common goal. With antimicrobial resistance rising to dangerously high levels in all parts of the world, how important is collaboration in this field?

Our project required expertise in various fields, such as microbiology, microscopy, microfluidics, programming, and data processing. In the development of rapid AST instruments and many others, only a multidisciplinary approach and close collaboration between teams with complementary expertise is today the only path to success.

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You and Dr. Willaert have said, ‘The simplicity and efficiency of the method make it a game-changer in the field of AST.’ Can you please expand on what makes ONMD a game changer in the AST field and what implications this research could have in clinical and research settings?

As mentioned earlier, bacterial resistance is a global health problem. Rapid AST should also be easily implemented in developing countries to limit the spread of resistant strains. The cheaper and simpler the technique, the more likely it is to be used on a large scale. We are convinced that the ONMD approach can meet these requirements. ONMD could also be used for drug discovery or basic research.

While we recognize the importance of rapid AST, what next steps must be taken before this technique can be used globally in research and clinical landscapes?

For fundamental research, there are no other important developments to be made. Any reasonably equipped research center can implement the technique and use it. Regarding implementing the technique in developing countries or extreme environments, stand-alone devices have to be used, which have yet to be manufactured.

There is a rapidly expanding need for efficient AST globally; however, the need for affordable, accessible, and simple techniques are of grave importance in developing countries disproportionately affected by antibiotic resistance due to existing global health disparities. Could this rapid AST technique be utilized in low-middle-income countries to slow the growing spread of multi-resistant bacteria? What would this mean for global health?

We are confident that ONMD-based AST testing can soon be implemented in research centers in both developed and developing countries. However, accreditation by the health authorities is necessary to use it as a standard diagnostic tool; this process can take several years, depending on the government health policy.

What’s next for you and your research? Are you involved in any exciting upcoming projects?

We want to develop a self-contained device for extreme environments. It would consist of a small microscope equipped with a camera and a data processing unit. The microfluidic part of the device could contain different antibiotics ready to be tested.

The ONMD technique could also monitor contamination levels in enclosed environments such as submarines, spacecraft, and space stations. One of our recent projects is funded by the European Space Agency (ESA) to develop a rapid antifungal susceptibility test that could work in microgravity. Additionally, ONMD could be used for even more exciting projects, such as chemistry-independent life detection in the search for extraterrestrial life.

Where can readers find more information?

  • Villalba MI, Rossetti E, Bonvallat A, Yvanoff C, Radonicic V, Willaert RG*, Kasas S.*.Simple optical nanomotion method for single-bacterium viability and antibiotic response testing. PNAS 2023, May 2;120(18):e2221284120. doi: 10.1073/pnas.2221284120. Epub 2023 Apr 24. PMID: 37094120. * Contributed equally. https://doi.org/10.1073/pnas.2221284120
  • Radonicic, V.; Yvanoff, C.; Villalba, M.I.; Devreese, B.; Kasas, S.; Willaert, R.G. Single-Cell Optical Nanomotion of Candida albicans in Microwells for Rapid Antifungal Susceptibility Testing. Fermentation 2023, 9:365. https://doi.org/10.3390/fermentation9040365
  • Parmar P, Villalba MI, Horii Huber AS, Kalauzi A, Bartolić D, Radotić K, Willaert RG, MacFabe DF and Kasas S. Mitochondrial nanomotion measured by optical microscopy. Front. Microbiol. 2023, 14:1133773. https://doi.org/10.3389/fmicb.2023.1133773
  • Starodubtseva MN, Irina A. Chelnokova IA, Shkliarava NM, Villalba MI, Tapalski DV, Kasas S, Willaert RG. Modulation of the nanoscale motion rate of Candida albicans by X-rays. Front. Microbiol. 2023, 14:1133027. https://doi.org/10.3389/fmicb.2023.1133027
  • Radonicic V, Yvanoff C, Villalba MI, Kasas S, Willaert RG. The Dynamics of Single-Cell Nanomotion Behaviour of Saccharomyces cerevisiae in a Microfluidic Chip for Rapid Antifungal Susceptibility Testing. Fermentation. 2022; 8(5):195. https://doi.org/10.3390/fermentation8050195

About Dr. Sandor Kasas

Nanomotion is a fascinating and novel approach to observing living organisms.

Our team focuses almost exclusively on recording the nanomotion of bacterial mitochondria and mammalian cells with optical and AFM-based devices.

Recently, we demonstrated that the technique could be used not only for fast antimicrobial sensitivity testing but also to explore the metabolism of unicellular organisms. We hope our efforts will permit us to expand the application domains of ONMD.

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Mouse study offers clues to developing an effective vaccine for Klebsiella bacteria

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A mouse study at Washington University School of Medicine in St. Louis points to data that could be key to developing an effective vaccine for the bacterium Klebsiella pneumoniae. The bug is often resistant to antibiotics, making it difficult to treat in some.

In the U.S., the bacterium Klebsiella pneumoniae is a common cause of urinary tract infection, bloodstream infection and pneumonia. While infections with the bacterium can be easily treated in some, Klebsiella has a dangerous flip side: It also is frequently resistant to antibiotics, making it extraordinarily difficult to treat in others. About half of people infected with a hypervirulent, drug-resistant strain of the bacterium die.

Scientists are working on vaccines for Klebsiella, but the optimal vaccine design is still unknown. However, a new study in mice by scientists at Washington University School of Medicine in St. Louis and Omniose, a St. Louis startup company specializing in vaccine production, provides critical data that could be key to developing an effective vaccine for Klebsiella. The findings, published in PLoS Pathogens, are a step toward taming the superbug.

When you think about the bugs that can be resistant to almost all antibiotics — the scary superbugs in the news — a lot of them are strains of Klebsiella. For a long time, the bacterium wasn’t even a pressing issue. But now it is, due to an explosion in antibiotic-resistant Klebsiella. Our goal is to diminish Klebsiella’s superbug status by developing a vaccine before hypervirulent or resistant strains sicken and kill even more people.”

David A. Rosen, MD, PhD, study’s senior author, assistant professor of pediatrics and of molecular microbiology at Washington University

Hypervirulent Klebsiella strains have spread globally, often causing community-acquired infections.

In the U.S., Klebsiella infections primarily occur in health-care facilities where medically vulnerable patients are immunocompromised, require long courses of antibiotics to treat other conditions, have chronic diseases, or are elderly people or newborns. “But now we’re seeing the emergence of hypervirulent strains dangerous enough to cause serious disease or death among healthy people in the community,” Rosen said.

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Most concerning among scientists are the strains of Klebsiella impervious to carbapenems, a class of broad-spectrum antibiotics used to treat the most severe bacterial infections. For this reason, the World Health Organization and the U.S. Centers for Disease Control and Prevention have identified carbapenem-resistant Klebsiella as an urgent threat to public health.

The rod-shaped bacterium is immobile and, like chocolate-covered candies, encapsulated in sugar coatings. In the new study, researchers created two experimental vaccines based on two different sugars, or polysaccharides, on Klebsiella’s surface: the terminal sugars on lipopolysaccharide, called O-antigen, and a capsular polysaccharide, or K-antigen. Since sugars by themselves tend to produce weak immune responses, the researchers linked each of the sugars to a protein to boost the immune response, creating so-called conjugate vaccines. Sugar-protein conjugate vaccines have proven successful in combating several bacteria including Streptococcus pneumoniae, the most common cause of pneumonia. Historically, this connection between the sugar and protein carrier has been achieved using synthetic chemistry in a test tube; however, the vaccines created for this study are called bioconjugate vaccines, because the researchers connected the sugar to the protein all within an engineered bacteria system.

Once the vaccines were created, the researchers tested the experimental bioconjugate vaccines’ ability to protect mice from disease caused by Klebsiella.

“It turned out that the capsule vaccine was far superior to the O-antigen vaccine,” said the study’s first author, Paeton Wantuch, PhD, a postdoctoral associate in Rosen’s lab. “Mice that received the capsule vaccine were significantly more likely to survive Klebsiella infection in their lungs or their bloodstream than mice that received the O-antigen vaccine.”

Both vaccines elicited high levels of antibodies against their respective targets. But the antibodies against the O-antigen just weren’t as effective as the ones against the capsule. In some strains of Klebsiella, the O-antigen may be obscured by other sugars, so the antibodies that target the O-antigen cannot make contact with their target.

“Our findings suggest that we may also need to include the capsule-based antigens in vaccine formulations developed against Klebsiella,” Rosen said. “This is why it’s so important for us to continue studying antibody-antigen interactions in the different strains, with the goal of identifying the ideal vaccine composition for clinical trials soon. The need has never been more imperative, especially as Klebsiella’s drug-resistant, hypervirulent strains become stronger, bolder and more dangerous to human health.”

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Source:
Journal reference:

Wantuch, P. L., et al. (2023) Area-deprivation, social care spending and the rates of children in care proceedings in local authorities in Engl Capsular polysaccharide inhibits vaccine-induced O-antigen antibody binding and function across both classical and hypervirulent K2:O1 strains of Klebsiella pneumoniae. PLOS Pathogens. doi.org/10.1371/journal.ppat.1011367.

Long-ignored antibiotic could help fight against multi-drug resistant bacteria

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“The end of modern medicine as we know it.” That’s how the then-director general of the World Health Organization characterized the creeping problem of antimicrobial resistance in 2012. Antimicrobial resistance is the tendency of bacteria, fungus and other disease-causing microbes to evolve strategies to evade the medications humans have discovered and developed to fight them. The evolution of these so-called “super bugs” is an inevitable natural phenomenon, accelerated by misuse of existing drugs and intensified by the lack of new ones in the development pipeline.

Without antibiotics to manage common bacterial infections, small injuries and minor infections become potentially fatal encounters. In 2019, more than 2.8 million antimicrobial-resistant infections occurred in the United States, and more than 35,000 people died as a result, according to the Centers for Disease Control and Prevention (CDC). In the same year, about 1.25 million people died globally. A report from the United Nations issued earlier this year warned that number could rise to ten million global deaths annually if nothing is done to combat antimicrobial resistance.

For nearly 25 years, James Kirby, MD, director of the Clinical Microbiology Laboratory at Beth Israel Deaconess Medical Center (BIDMC), has worked to advance the fight against infectious diseases by finding and developing new, potent antimicrobials, and by better understanding how disease-causing bacteria make us sick. In a recent paper published in PLOS Biology, Kirby and colleagues investigated a naturally occurring antimicrobial agent discovered more than 80 years ago.

Using leading-edge technology, Kirby’s team demonstrated that chemical variants of the antibiotic, called streptothricins, showed potency against several contemporary drug-resistant strains of bacteria. The researchers also revealed the unique mechanism by which streptothricin fights off bacterial infections. What’s more, they showed the antibiotic had a therapeutic effect in an animal model at non-toxic concentrations. Taken together, the findings suggest streptothricin deserves further pre-clinical exploration as a potential therapy for the treatment of multi-drug resistant bacteria.

We asked Dr. Kirby to tell us more about this long-ignored antibiotic and how it could help humans stave off the problems of antimicrobial resistance a little longer.

Q: Why is it important to look for new antimicrobials? Can’t we preserve the drugs we have through more judicious use of antibiotics?

Stewardship is extremely important, but once you’re infected with one of these drug-resistant organisms, you need the tools to address it.

Much of modern medicine is predicated on making patients temporarily — and sometimes for long periods of time — immunosuppressed. When these patients get colonized with these multidrug-resistant organisms, it’s very problematic. We need better antibiotics and more choices to address multidrug resistance.

We have to realize that this is a worldwide problem, and organisms know no borders. So, a management approach for using these therapies may work well in Boston but may not in other areas of the world where the resources aren’t available to do appropriate stewardship.

Q: Your team investigated an antimicrobial discovered more than 80 years ago. Why was so little still known about it?

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The first antibiotic, penicillin, was discovered in 1928 and mass produced for the market by the early 1940s. While a game-changing drug, it worked on only one of the two major classes of bacteria that infect people, what we call gram-positive bacteria. The gram-positive bacteria include staphylococcal infections and streptococcal infections which cause strep throat, skin infections and toxic shock. There still was not an antibiotic for the other half of bacteria that can cause human infections, known as gram-negative organisms.

In 1942, scientists discovered this antibiotic that they isolated from a soil bacterium called streptothricin, possibly addressing gram-negative organisms. A pharmaceutical company immediately licensed the rights to it, but the development program was dropped soon after when some patients developed renal or kidney toxicity. Part of the reason for not pursuing further research was that several additional antibiotics were identified soon thereafter which were also active against gram-negatives. So, streptothricin got shelved.

Q: What prompted you to look at streptothricin specifically now?

It was partly serendipity. My research laboratory is interested in finding new, or old and forgotten, solutions to treat highly drug-resistant gram-negative pathogens like E. coli or Klebsiella or Acinetobacter that we commonly see in hospitalized, immunocompromised patients. The problem is that they’re increasingly resistant to many if not all of the antibiotics that we have available.

Part of our research is to understand how these superbugs cause disease. To do that, we need a way to manipulate the genomes of these organisms. Commonly, the way that’s done is to create a change in the organism linked with the ability to resist a particular antibiotic that’s known as a selection agent. But for these super resistant gram-negative pathogens, there was really nothing we could use. These bugs were already resistant to everything.

We started searching around for drugs that we could use, and it turns out these super resistant bugs were highly susceptible to streptothricin, so we were able to use it as a selection agent to do these experiments.

As I read the literature on streptothricin and its history, I had the realization that it was not sufficiently explored. Here was this antibiotic with outstanding activity against gram-negative bacteria – and we confirmed that by testing it against a lot of different pathogens that we see in hospitals. That raised the question of whether we could get really good antibiotic activity at concentrations that are not going to cause damage to the animal or person in treatment.

Q: But it did cause kidney toxicity in people in 1942. What would be different now?

What scientists were isolating in 1942 was not as pure as what we are working with today. In fact, what was then called streptothricin is actually a mixture of several streptothricin variants. The natural mixture of different types of streptothricins is now referred to as nourseothricin.

In animal models, we tested whether we could kill the harmful microorganism without harming the host using a highly purified single streptothricin variant. We used a very famous strain of Klebsiella pneumoniae called the Nevada strain which was the first pan-drug-resistant, gram-negative organism isolated in the United States, an organism for which there was no treatment. A single dose cleared this organism from an infected animal model while avoiding any toxicity. It was really remarkable. We’re still in the very early stages of development, but I think we’ve validated that this is a compound that’s worth investing in further studies to find even better variants that eventually will meet the properties of a human therapeutic.

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Q. How does nourseothricin work to kill gram-negative bacteria?

That’s another really important part of our study. The mechanism hadn’t been figured out before and we showed that nourseothricin acts in a completely new way compared to any other type of antibiotic.

It works by inhibiting the ability of the organism to produce proteins in a very sneaky way. When a cell makes proteins, they make them off a blueprint or message that tells the cell what amino acids to link together to build the protein. Our studies help explain how this antibiotic confuses the machinery so that the message is read incorrectly, and it starts to put together gibberish. Essentially the cell gets poisoned because it’s producing all this junk.

In the absence of new classes of antibiotics, we’ve been good at taking existing drugs like penicillin for example and modifying them; we’ve been making variations on the same theme. The problem with that is that the resistance mechanisms against penicillin and other drugs already exist. There’s a huge environmental reservoir of resistance out there. Those existing mechanisms of resistance might not work perfectly well against your new variant of penicillin, but they will evolve very quickly to be able to conquer it.

So, there’s recognition that what we really want is new classes of antibiotics that act in a novel way. That’s why streptothricin’s action uncovered by our studies is so exciting. It works in a very unique way not seen with any other antibiotic, and that is very powerful because it means there’s not this huge environmental reservoir of potential resistance.

Q. You emphasize these are early steps in development. What are the next steps?

My lab is working very closely with colleagues at Northeastern University who figured out a way to synthesize streptothricin from scratch in a way that will allow us to cast many different variants. Then we can look for ones that have the ideal properties of high potency and reduced toxicity.

We are also continuing our collaboration with scientists at Case Western Reserve University Medical Center, diving more deeply to understand exactly how this antibiotic works. Then we can use that fundamental knowledge in our designs of future variants and be smarter about how we try to make the best antibiotic.

We have great collaborators that have allowed us to pursue a project that crosses multiple fields. This work is an example of collaborative science really at its best.

Co-authors included first author Christopher E. Morgan and Edward W. Yuof Case Western Reserve; Yoon-Suk Kang,Alex B. Green, Kenneth P. Smith, Lucius Chiaraviglio, Katherine A. Truelson, Katelyn E. Zulauf, Shade Rodriguez, and Anthony D. Kang of BIDMC; Matthew G. Dowgiallo,Brandon C. Miller, and Roman Manetsch of Northeastern University.

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New compound with antibacterial activity shows promising results within one hour in laboratory trials

Resistance to antibiotics is a problem that alarms the medical and scientific community. Bacteria resistant to three different classes of antibiotics, known as multi-drug resistant (MDR) bacteria, are far from rare. Some are even resistant to all currently available treatments and are known as pan-drug resistant (PDR). They are associated with dangerous infections and listed by the World Health Organization (WHO) as priority pathogens for drug development with maximum urgency.

An article published in a special issue of the journal Antibiotics highlights a compound with antibacterial activity that presented promising results within one hour in laboratory trials.

The study was led by Ilana Camargo, last author of the article, and conducted during the doctoral research of first author Gabriela Righetto at the Molecular Epidemiology and Microbiology Laboratory (LEMiMo) of the University of São Paulo’s São Carlos Institute of Physics (IFSC-USP) in Brazil.

The compound we discovered is a new peptide, Pln149-PEP20, with a molecular framework designed to enhance its antimicrobial activity and with low toxicity. The results can be considered promising insofar as the trials involved pathogenic bacteria associated with MDR infections worldwide.”

Adriano Andricopulo, co-author of the article

Although novel antibacterial drugs are urgently needed, the pharmaceutical industry is notoriously uninterested in pursuing them, mainly because research in this field is time-consuming and costly, requiring very long lead times to bring viable active compounds to market.

The Center for Innovation in Biodiversity and Drug Discovery (CIBFar), a Research, Innovation and Dissemination Center (RIDC) set up and funded by FAPESP, looks for molecules that can be used to combat multidrug-resistant bacteria.

Camargo and Andricopulo are researchers at CIBFar, as are two other co-authors who study promising bactericidal compounds: Leila Beltramini and José Luiz Lopes.

For over a decade, the group formed by the collaboration between Beltramini and Lopes has analyzed Plantaricin 149 and its analogs. Plantaricins are substances produced by the bacterium Lactobacillus plantarum to combat other bacteria.

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Lactobacillus plantarum is commonly found in nature, especially in anaerobic plant matter, and in many fermented vegetable, meat and dairy products.

In the case of Plantaricin 149, Japanese researchers were the first to report its bactericidal action (in 1994) and since then scientists have been interested in obtaining more efficient synthetic analogs (molecules with small structural differences). In 2007, one of the first projects completed by the CIBFar team showed that the peptide inhibits pathogenic bacteria such as Listeria spp. and Staphylococcus spp. They then began studying synthetic analogs with stronger bactericidal activity than the original (causing more damage to the membrane of the combated microorganisms).

With the support of a scholarship from FAPESP, Righetto synthesized 20 analogs of Plantaricin 149, finding that Pln149-PEP20 had the best results so far and was also half the size of the original peptide. “The main advances in our research consist of the development of this smaller, more active and less toxic molecule, and the characterization of its action and propensity to develop resistance. It has proven to be highly promising in vitro – active against MDR bacteria and extensively resistant bacteria,” said Camargo, principal investigator for the project.

LEMiMo, the laboratory where the studies were conducted, has experience in characterizing bacterial isolates involved in outbreaks of hospital infections and holds a collection of bacteria selected for these trials in search of novel active compounds. The bacteria have the resistance profiles currently of greatest concern and were isolated during hospital outbreaks.

They are known in the scientific community by the term ESKAPE, an acronym for the scientific names of six highly virulent and antibiotic-resistant bacterial pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.

Further research can now be conducted to investigate the molecule’s action mechanism in more depth, to look for formulations, and possibly to develop an application. “In terms of the action mechanism, it’s also possible to use the cell morphology of the bacteria to identify cellular pathways affected by the peptide,” Righetto said. “As for optimization, the molecule can be functionalized by being linked to macrostructures, and the amino acid sequence can be modified.” Research is also needed on its cytotoxicity and on its selectivity (whether it affects healthy cells).

“We’re living in times of major global public health hazards due to a lack of antimicrobials that can be used to treat infections caused by extremely resistant bacteria. Antimicrobial peptides are targets of great interest for the development of novel candidate drugs. This novel molecule has the potential to be used as an innovative antimicrobial therapy, but further modifications and molecular optimizations still need to be investigated,” Andricopulo said.

Publication of the article also involved Harvard Medical School’s Infectious Disease Institute in Boston (USA) via researchers Paulo José Martins Bispo and Camille André.

Source:
Journal reference:

Righetto, G. M., et al. (2023). Antimicrobial Activity of an Fmoc-Plantaricin 149 Derivative Peptide against Multidrug-Resistant Bacteria. doi.org/10.3390/antibiotics12020391.

MGI Empowers the Completion of Nearly 60,000 Samples for The Million Microbiome of Humans Project

SHENZHEN, China, 10 May 2023 – MGI Tech Co. Ltd. (MGI), a company committed to building core tools and technology to lead life science, today shared that a total of nearly 60,000 samples have been sequenced among 21 institutes and over 10 participating nations throughout Europe, as part of the Million Microbiome of Humans Project (MMHP) that was officially launched in 2019.

Image Credit: MGI

The project was launched as a joint effort by the Karolinska Institute of Sweden, Shanghai National Clinical Research Center for Metabolic Diseases in China, the University of Copenhagen in Denmark, Technical University of Denmark, MetaGenoPolis at the National Research Institute for Agriculture, Food and Environment (INRAE) in France, and the Latvian Biomedical Research and Study Center. Relying on MGI’s core DNBSEQ™ technology, MMHP aims to sequence and analyze microbial DNA from a million human samples to construct a microbiome map of the human body and build the world’s largest human microbiome database.

“Countless studies have highlighted the importance of the microbiome in human health and disease. Yet, our knowledge of the composition of the microbiome in different parts of the body across countries, ages, sexes, and in relation to human health and disease remains limited,” said Duncan Yu, President of MGI. “Through MMHP, we are pushing forward microbial metagenomic research while empowering researchers within the microbiology community with access to MGI’s innovative sequencing technology. Despite a brief interruption by the COVID-19 pandemic, we are delighted to see such a monumental milestone merely four years into the project.”

The rise of microbial metagenomic sequencing​​​​​​​

Since the first description of human microbiome was published in 2010, the field of human microbiome has moved fast from sampling hundreds of individuals to thousands. Advances in genome sequencing has enabled researchers to better characterize the composition of the microbiome through identification of unculturable microbes. It has also allowed them the opportunity to study how the microbiome influences the development of some cancers and drug responses.

Metagenomics, coupled with high-throughput sequencing technologies, have revolutionized microbial ecology. Today, metagenomic sequencing has become both a powerful and popular tool for identifying and classifying complex microbial communities. It facilitates accelerated discovery of new markers that translate to virulence or antibiotic resistance, as well as de novo discovery and characterization of novel species and assembly of new genomes. Besides human microbiome, it is highly applicable in agricultural microbiome studies, environmental microbiome studies, pathogen surveillance and identification, and monitoring of antimicrobial resistance genes.

Indeed, the global metagenomic sequencing market was estimated to be worth USD 1.86 billion in revenue in 2022 and is poised to reach USD 4.33 billion by 2027, growing at a CAGR of 18.4% during the forecast period. In particular, Europe and Africa account for approximately 29.7% market share from the globe, ranking second after North America at 45.6%. Thanks to continuous technological innovations in high-throughput sequencing platforms, the metagenomic sequencing market within Europe and Africa is projected to grow from USD 551.7 million in 2022 to 1.29 billion by 2027, presenting huge market opportunities and providing local institutions with the impetus to invest and get involved.

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Image Credit: MGI

An optimized workflow with MGI’s cutting-edge technology

Equipped with MGI’s innovative lab systems, the MMHP Consortium guarantees high-throughput processes, extreme precision, and high quality data output. The dedicated, one-stop workflow begins with sample transfer on MGISTP-7000* high-throughput automated sample transfer processing system. It then goes through nucleic acid extraction and library preparation on MGISP-960 high-throughput automated sample preparation system, a flexible and fully automated workstation capable of processing 96 samples per run. MGISP-960’s fully automatic operation design allows DNA extraction of 50,000 samples per year and library preparation of 25,000 samples per year. MGISP-Smart 8, the professional automated pipetting robot, equipped with an independent 8 pipetting channel can be used for the pooling, normalization and DNB making. Lastly, DNBSEQ-T7* ultra-high throughput sequencer and DNBSEQ-G400* versatile benchtop sequencer enables an efficient, productive, and streamlined sequencing experience.

“We are very focused on data quality, cost and time. After contrasting DNBSEQ™ technology by MGI with other sequencing technologies, we are convinced that MGI’s products have met high industry standards and provide a very good user experience,” commented Professor Lars Engstrand, Research Director of Center for Microbial Translational Research (CMTR) at Karolinska Institutet. “MGI’s platforms have enabled our team to upgrade our original microbiological research from 16SrRNA gene amplicon sequencing to shotgun metagenomic sequencing. I look forward to introducing more equipment and super-large projects as human microbiome emerges as a crucial diagnostic and treatment method in precision medicine.”

The next chapter in microbiomics

“Microbiomics will be part of precision medicine in the future, and data from the microbiome biobank that will result from MMHP will be leveraged for therapeutic R&D,” said Professor Stanislav Dusko Ehrlich of University College London, UK. “With 21 public and private institutions and 10+ countries currently involved in MMHP, we are actively looking for more research groups to take part in this landmark international microbiological research partnership and help generate the world’s biggest free-access human microbiome database.”

Since the inception of MMHP, MGI has played an important role in providing the program with state-of-the-art research platforms and technologies. Now entering its second phase towards sequencing and analyzing a final total of one million samples, the project welcomes further exchange and participation from relevant organizations to jointly promote research and applications of cutting-edge translational medicine in the field of microbiome. Those interested can fill the application form on www.mgi-tech.eu/mmhp.

About MGI

MGI Tech Co. Ltd. (MGI), headquartered in Shenzhen, is committed to building core tools and technology to lead life science through intelligent innovation. Based on its proprietary technology, MGI focuses on research & development, production and sales of sequencing instruments, reagents, and related products to support life science research, agriculture, precision medicine and healthcare. MGI is a leading producer of clinical high-throughput gene sequencers*, and its multi-omics platforms include genetic sequencing*, medical imaging, and laboratory automation. MGI’s mission is to develop and promote advanced life science tools for future healthcare. For more information, please visit the MGI website or connect with us on TwitterLinkedIn or YouTube.

*Unless otherwise informed, StandardMPS and CoolMPS sequencing reagents, and sequencers for use with such reagents are not available in Germany, Spain, UK, Sweden, Italy, Czech Republic, Switzerland and Hong Kong (CoolMPS is available in Hong Kong).

*For Research Use Only. Not for use in diagnostic procedures (except as specifically noted).

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Breast milk microbes shape infant gut health

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A new paper published in the Frontiers in Microbiology explores the contribution of human breast milk to the establishment of the infant gut microbiome.

Study: Human milk-associated bacterial communities associate with the infant gut microbiome over the first year of life. Image Credit: Pavel Ilyukhin / Shutterstock.com Study: Human milk-associated bacterial communities associate with the infant gut microbiome over the first year of life. Image Credit: Pavel Ilyukhin / Shutterstock.com

Introduction

Breastfeeding is encouraged as the first and exclusive food of infants for at least the first six months of life. In addition to its nutritional content, breast milk contributes significantly to the formation of the infant gut microbiome. This is because of its high content of immune cells, oligosaccharides carrying glycosyl residues, fatty acids, and some microbes.

Both breast milk bacteria and skin microbes from the maternal nipple reach and establish themselves in the infant’s gut. Bacteria may be shielded by secretory immunoglobulin A (sIgA) covering the immune system, thus allowing them to enter the gut intact.   

The infant gut microbiome (IGMB) is important for both infant development and immunity, as well as modulating conditions like atopy and body mass composition. However, earlier research on potential associations between the IGMB and breast milk microbiota has been limited to analyzing samples from corresponding time points.

The current study included almost 190 dyads from New Hampshire. Breast milk and infant stool samples were collected at around six weeks, four months, six months, nine months, and one year from birth, which allowed the scientists to identify correlations that developed over time.

What did the study show?

In the study population, with a mean age of 32 years, most were White and had a normal body mass index (BMI) during pregnancy. About 25% of deliveries occurred through Cesarean section (C-section), and antibiotic exposure prior to lactation occurred in over half of mothers.

Most babies were almost full term at birth, with only 3% being exposed to antibiotics by four months of life. By one year, about 30% of infants had been exposed to antibiotics.

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About 75% and 40% of infants did not receive any formula up to six weeks and four months, respectively. Most infants began eating solid food by six months.

Three breast milk microbiome types (BMTs) were identified in the six-week breast milk samples. These could be differentiated by the relative proportions of four bacterial genera, including Streptococcus, Staphylococcus, Pseudomonas, and Acinetobacter, as well as by the microbial diversity.

At six weeks, the gut microbiome in infants exhibited four six-week infant gut microbiome types (6wIGMTs). These had different abundances of Bifidobacterium, Bacteroides, Clostridium, Streptococcus, and Escherichia/Shigella.

The 6wIGMT correlated with the 6wBMT in male infants and those born by C-section. Notably, the same microbe was likely to be the most abundant within the dyads at this point.

By age one, the predominant difference in microbiome composition was due to Bacteroides. There was no association between the 6wBMT and 12mIGMT, which is likely due to the intake of solid foods by infants at this age. The transition to a primarily solid diet causes the infant microbiome to be dominated by other microbes, such as Bifidobacterium and Bacteroidetes, both of which are more abundant in the adult gut.

At six weeks, the BMT was associated with 6wIGMT in all infants but more strongly in male infants born by C-section. Male infants also had a higher proportion of microbes from breast milk present in their stool.

While infants delivered by C-section have a reduced colonization by maternal stool microbiota, their colonization by breast milk microbiota is higher than vaginally delivered infants.”

This could be due to the reduced microbial diversity and Bacteroides depletion in the IGMB of C-section-delivered infants, which makes it easier for breast milk microbes to colonize the gut.

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Male infants appeared to show a greater effect of the breast milk microbes on their gut microbiome. This may be because they exhibit less microbial diversity, with fewer Clostridiales and more Enterobacteriales abundance than is observed in female infants. The male infant’s gut microbiota is also more susceptible to stress and environmental exposures.

Overall, the breast milk microbial communities correlated most strongly with those found in infant stool samples that were collected at a later time point. For example, Pantoea in breast milk at four and six months was correlated with infant stool collected at nine and twelve months, respectively. These findings require further validation in future research.

What are the implications?

The identification of microbial clusters in human milk and infant feces that were shared within the mother-infant pair at six weeks is a striking finding in this study. The delay in cluster sharing and the association with C-section were associated with stronger correlations.

The findings of this study agree with earlier reports on the associations of various microbes in breast milk and the infant gut. Notably, the current study adds to previous data by identifying correlations between different taxa in these two sites.

The scientists postulate that microbes within communities may show direct interactions, such as the transmission of a microbe present in the infant oral cavity to the breast in this case, as well as the intake of breast milk by the infant. In addition, they may show indirect interactions through nutrients like fatty acids and milk sugars or other bacterial metabolites that influence both communities.

With the observed shift in breast milk microbial diversity over time, long-term studies may be needed to understand the breadth of microbial exposures during infancy. The change in IGMTs over time should also be better characterized and their relevance assessed.

These results suggest that milk microbial communities have a long-term effect on the infant gut microbiome both through sharing of microbes and other molecular mechanisms.”

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Journal reference:
  • Lundgren, S. N., Madan, J. C., Karagas, M. R., et al. (2023). Human milk-associated bacterial communities associate with the infant gut microbiome over the first year of life. Frontiers in Microbiology. doi:10.3389/fmicb.2023.1164553.

Diet has a much stronger impact on intestinal microbiota than defensins

Researchers at Umeå University, Sweden, have found that among the many factors that shape the intestinal microbiota composition, diet has a much stronger impact than defensins, which are intestinal defence molecules produced by the body. Instead, they identified a possible role for these molecules in preventing increased blood glucose levels after consumption of high-caloric “Western-style diet”.

While the effect of defensins in shaping the adult microbiota composition is rather minor when compared to diet, defensins still have a very important role in protecting us against microbial infections; and our research highlights their protective role against the metabolic complications that can arise after the intake of a high-fat and high-sugar Western-style diet.”

Fabiola Puértolas Balint, PhD Student at the Department of Molecular Biology at Umeå University

She is working in Björn Schröder’s research group, which is also affiliated to Umeå Centre of Microbial Research, UCMR, and The Laboratory for Molecular Infection Medicine Sweden, MIMS, at Umeå University.

The gut microbiota refers to the community of trillions of microorganisms that live inside everyone’s gut. Over the past decades, the abundance of specific bacteria in this community has been extensively studied due to its connection to many diseases, including inflammatory bowel diseases, obesity and diabetes, and even psychological disorders. The microbial community is seeded during birth, after which several internal and external factors help shaping the community to its final composition. These factors include, among others, diet (especially fibre), genetics, medication, exercise, and defence molecules, the so-called antimicrobial peptides.

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Antimicrobial peptides can be regarded as the body´s own naturally produced antibiotic molecules. In particular, the largest group of antimicrobial peptides – the defensins – is produced by all body surfaces, including the skin, the lungs and the gastrointestinal tract. Defensins are considered the immune system´s first line of defence against infections but at the same time they have also been thought to be essential in shaping the microbiota composition in the small intestine. However, it was so far unclear how big their effect was as compared to diet, which is known to have a major impact.

To investigate this, the researchers from Björn Schröder lab used normal healthy mice and compared their microbiota composition in the small intestine to mice that could not produce functional defensins in the gut, and then both mouse groups were fed either a healthy diet or a low-fibre Western-style diet.
“When we analysed the microbiota composition inside the gut and at the gut wall of two different regions in the small intestine, we were surprised – and slightly disappointed – that defensins had only a very minor effect on shaping the overall microbiota composition,” says Björn Schröder.
However, the intestinal defensins still had some effect directly at the gut wall, where the defensins are produced and secreted. Here, a few distinct bacteria seemed to be affected by the presence of defensins, among them Dubosiella and Bifidobacteria, likely due to selective antimicrobial activity of the defensins.

“To our surprise, we also found that the combination of eating a Western-style diet and lacking functional defensins led to increased fasting blood glucose values, which indicated that defensins may help to protect against metabolic disorders when eating an unhealthy diet,” says Björn Schröder.
The results suggest that strategies that aim to positively modulate the microbiota composition should rather focus on diet, as modulation of the composition via increased production of own host defense molecules, such as defensins, may have only a small impact on the overall composition. However, it is possible that especially early in life, when the microbiota community is not fully matured yet, defensins may have a stronger effect on the microbial composition. Still, increasing the production of defensins may be a valuable option to prevent the development of metabolic disorders.

The results have been published in the scientific journal Microbiology Spectrum.

Source:
Journal reference:

Puértolas-Balint, F., & Schroeder, B. O. (2023). Intestinal α-Defensins Play a Minor Role in Modulating the Small Intestinal Microbiota Composition as Compared to Diet. Microbiology Spectrum. doi.org/10.1128/spectrum.00567-23.

Discontinuing oral antibiotics after breast reconstruction does not lead to an increase in infections

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For breast cancer patients undergoing breast reconstruction after mastectomy, avoiding postoperative oral antibiotics does not reduce the risk of infections, reports a study in the May issue of Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS). The journal is published in the Lippincott portfolio by Wolters Kluwer.

Our experience suggests that discontinuing routine oral antibiotic treatment after implant-based breast reconstruction does not lead to an increase in surgical site infections, and will eliminate a small but significant risk of allergy and other antibiotic-related complications.”

Mark Sisco, MD, ASPS Member Surgeon, NorthShore University HealthSystem, Evanston, Ill

No increase in infections after policy change on preventive antibiotics

A growing number of breast cancer patients are undergoing breast reconstruction after mastectomy, particularly immediate reconstruction using implants. Surgical site infections (SSIs) occur in 10% to 25% of patients undergoing this procedure, leading to increased rates of hospital readmission, repeat surgery, and reconstructive failure.

Historically, plastic surgeons have given extended antibiotic prophylaxis (EAP) to reduce the risk of SSI. The use of postoperative oral antibiotics has continued despite a lack of evidence for its effectiveness, and amid rising concerns about antibiotic resistance. In 2016, the authors’ health system joined the growing trend toward ending routine EAP for post-mastectomy breast reconstruction.

To evaluate the impact of this practice change, Dr. Sisco and colleagues compared outcomes in two groups of patients: 654 women (1,004 breasts) receiving EAP and 423 women (683 breasts) not receiving postoperative oral antibiotics. Both groups received a single dose of intravenous antibiotic before surgery.

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After surgery, the overall infection rate was similar between groups: 7.9% with EAP and 9.1% without EAP. After adjustment for differences in patient characteristics, the risk of SSIs was not significantly different between groups. This was even though patients in the non-EAP were more likely to receive some newer techniques – including nipple-sparing mastectomy and pre-pectoral (“above the muscle”) implant placement – thought to carry an increased risk of complications.

‘Thousands of women nationwide’ may have adverse reactions to EAP

Meanwhile, patients receiving EAP had some “infrequent but not insignificant” adverse events, including a two percent rate of moderate to severe allergic reactions. At least four women in the EAP group developed infection with antibiotic-resistant Clostridium difficile (“C-diff”) bacteria. Neither of these complications occurred in patients who did not receive extended antibiotics.

There was also evidence that EAP affected the types of bacteria isolated from patients who developed infections, including a higher rate of gram-negative bacteria. Extended antibiotic use was associated with a “broader range of pathogens” and more frequent need for second-line intravenous antibiotics.

“Although the use of EAP does not appear to worsen clinical outcomes, marked differences in the microbiology of associated infections may make them more difficult to treat,” Dr. Sisco and coauthors write. Especially at a time when breast reconstruction rates are rapidly increasing, “Our findings suggest that thousands of women are having adverse reactions to EAP nationwide, and some of these are likely to be serious,” the researchers add.

While acknowledging some important limitations of their study, the authors note that a definitive randomized trial of ending routine EAP is unlikely to be performed. Dr. Sisco and colleagues conclude, “We hope that our experience will give surgeons additional evidence and courage to change their practice.”

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Source:
Journal reference:

Sisco, M., et al. (2022). Oral antibiotics do not prevent infection or implant loss after immediate prosthetic breast reconstruction: Evidence from 683 consecutive reconstructions without prophylaxis. Plastic & Reconstructive Surgery. doi.org/10.1097/prs.0000000000010073

Bioengineered drug candidate can counter S. aureus infection in early tests

Researchers at NYU Grossman School of Medicine and Janssen Biotech, Inc. have shown in early tests that a bioengineered drug candidate can counter infection with Staphylococcus aureus – a bacterial species widely resistant to antibiotics and a major cause of death in hospitalized patients.

Experiments demonstrated that SM1B74, an antibacterial biologic agent, was superior to a standard antibiotic drug at treating mice infected with S. aureus, including its treatment-resistant form known as MRSA.

Published online April 24 in Cell Host & Microbe, the new paper describes the early testing of mAbtyrins, a combination molecule based on an engineered version of a human monoclonal antibody (mAb), a protein that clings to and marks S. aureus for uptake and destruction by immune cells. Attached to the mAb are centyrins, small proteins that prevent these bacteria from boring holes into the human immune cells in which they hide. As the invaders multiply, these cells die and burst, eliminating their threat to the bacteria.

Together, the experimental treatment targets ten disease-causing mechanisms employed by S. aureus, but without killing it, say the study authors. This approach promises to address antibiotic resistance, say the researchers, where antibiotics kill vulnerable strains first, only to make more space for others that happen to be less vulnerable until the drugs no longer work.

To our knowledge, this is the first report showing that mAbtyrins can drastically reduce the populations of this pathogen in cell studies, and in live mice infected with drug-resistant strains so common in hospitals. Our goal was to design a biologic that works against S. aureus inside and outside of cells, while also taking away the weapons it uses to evade the immune system.”

Victor Torres, PhD, Lead Study Author, the C.V. Starr Professor of Microbiology and director of the NYU Langone Health Antimicrobial-Resistant Pathogen Program

One-third of the human population are carriers of S. aureus without symptoms, but those with weakened immune systems may develop life-threatening lung, heart, bone, or bloodstream infections, especially among hospitalized patients.

Inside out

The new study is the culmination of a five-year research partnership between scientists at NYU Grossman School of Medicine and Janssen to address the unique nature of S. aureus.

The NYU Langone team together with Janssen researchers, published in 2019 a study that found that centyrins interfere with the action of potent toxins used by S. aureus to bore into immune cells. They used a molecular biology technique to make changes in a single parental centyrin, instantly creating a trillion slightly different versions of it via automation. Out of this “library,” careful screening revealed a small set of centyrins that cling more tightly to the toxins blocking their function.

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Building on this work, the team fused the centyrins to a mAb originally taken from a patient recovering from S. aureus infection. Already primed by its encounter with the bacteria, the mAb could label the bacterial cells such that they are pulled into bacteria-destroying pockets inside of roving immune cells called phagocytes. That is unless the same toxins that enable S. aureus to drill into immune cells from the outside let it drill out of the pockets to invade from the inside.

In a “marvel of bioengineering,” part of the team’s mAbtyrin serves as the passport recognized by immune cells, which then engulf the entire, attached mAbtyrin, along with its centyrins, and fold it into the pockets along with bacteria. Once inside, the centyrins block the bacterial toxins there. This, say the authors, sets their effort apart from antibody combinations that target the toxins only outside of cells.

The team made several additional changes to their mAbtyrin that defeat S. aureus by, for instance, activating chain reactions that amplify the immune response, as well by preventing certain bacterial enzymes from cutting up antibodies and others from gumming up their action.

In terms of experiments, the researchers tracked the growth of S. aureus strains commonly occurring in US communities in the presence of primary human immune cells (phagocytes). Bacterial populations grew almost normally in the presence of the parental antibody, slightly less well in the presence of the team’s engineered mAb, and half as fast when the mAbtyrin was used.

In another test, 98% of mice treated with a control mAb (no centyrins) developed bacteria-filled sores on their kidneys when infected with a deadly strain of S. aureus, while only 38% of mice did so when treated with the mAbtyrin. Further, when these tissues were removed and colonies of bacteria in them counted, the mice treated with the mAbtyrin had one hundred times (two logs) fewer bacterial cells than those treated with a control mAb.

Finally, the combination of small doses of the antibiotic vancomycin with the mAbtyrin in mice significantly improved the efficacy of the mAbtyrin, resulting in maximum reduction of bacterial loads in the kidneys and greater than 70% protection from kidney lesions.

“It is incredibly important,” said Torres, “that we find new ways to boost the action of vancomycin, a last line of defense against MRSA.”

Along with Torres, authors from the Department of Microbiology at NYU Langone were Rita Chan, Ashley DuMont, Keenan Lacey, Aidan O’Malley, and Anna O’keeffe. The study authors included 13 scientists from Janssen Research & Development (for details see the study manuscript).

This work was supported by Janssen Biotech, Inc., one of the Janssen Pharmaceutical Companies of Johnson & Johnson, under the auspices of an exclusive license and research collaboration agreement with NYU. Torres has recently received royalties and consulting compensation from Janssen and related entities. These interests are being managed in accordance with NYU Langone policies and procedures.

Source:
Journal reference:

Buckley, P. T., et al. (2023). Multivalent human antibody-centyrin fusion protein to prevent and treat Staphylococcus aureus infections. Cell Host & Microbe. doi.org/10.1016/j.chom.2023.04.004.