Tag: antibiotics

Categories : Antibiotics CancerTags :

Old Antibiotics as New Weapons against Melanoma

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Researchers may have hit upon a new weapon in the fight against melanoma: antibiotics that target a vulnerability in the ‘power plants’ of cancer cells when they try to survive cancer therapy.

“As the cancer evolves, some melanoma cells may escape the treatment and stop proliferating to ‘hide’ from the immune system. These are the cells that have the potential to form a new tumor mass at a later stage,” explains cancer researcher and RNA biologist Eleonora Leucci at KU Leuven, Belgium. “In order to survive the cancer treatment however, those inactive cells need to keep their ‘power plants’—the mitochondria—switched on at all times.” As mitochondria derive from bacteria that, over time, started living inside cells, they are very vulnerable to a specific class of antibiotics. This is what gave us the idea to use these antibiotics as anti-melanoma agents.”

The researchers implanted patient-derived tumors into mice, which were then treated with antibiotics, either as alone or in combined with existing anti-melanoma therapies. Leucci observed: “The antibiotics quickly killed many cancer cells and could thus be used to buy the precious time needed for immunotherapy to kick in. In tumors that were no longer responding to targeted therapies, the antibiotics extended the lifespan of—and in some cases even cured—the mice.”

The researchers made use of nearly antibiotics rendered nearly obsolete because of antibiotic resistance. However, this does not affect the efficacy of the treatment in this study, Leucci explained. “The cancer cells show high sensitivity to these antibiotics, so we can now look to repurpose them to treat cancer instead of bacterial infections.”

However, patients with melanoma should not try to experiment, warned Leucci. “Our findings are based on research in mice, so we don’t know how effective this treatment is in human beings. Our study mentions only one human case where a melanoma patient received antibiotics to treat a bacterial infection, and this re-sensitized a resistant melanoma lesion to standard therapy. This result is cause for optimism, but we need more research and clinical studies to examine the use of antibiotics to treat cancer patients. Together with oncologist Oliver Bechter (KU Leuven/UZ Leuven), who is a co-author of this study, we are currently exploring our options.”

Source: KU Leuven

Journal information: Roberto Vendramin et al, Activation of the integrated stress response confers vulnerability to mitoribosome-targeting antibiotics in melanoma, Journal of Experimental Medicine (2021). DOI: 10.1084/jem.20210571

Categories : Antibiotics Obstetrics & Gynaecology PaediatricsTags :

In Utero or Neonatal Antibiotic Exposure Could Lead to Brain Disorders

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Image by Ahmad Ardity from Pixabay
Image by Ahmad Ardity from Pixabay

According to a new study, antibiotic exposure early in life could alter human brain development in areas responsible for cognitive and emotional functions.

The study suggests that penicillin alters the body’s microbiome as well as gene expression, which allows cells to respond to its changing environment, in key areas of the developing brain. The findings, published in the journal iScience, suggest reducing widespread antibiotic use or using alternatives when possible to prevent neurodevelopment problems.
Penicillin and related medicines, such as ampicillin and amoxicillin, are the most widely used antibiotics in children worldwide. In the United States, the average child receives nearly three courses of antibiotics before age 2, and similar or greater exposure rates occur elsewhere.

“Our previous work has shown that exposing young animals to antibiotics changes their metabolism and immunity. The third important development in early life involves the brain. This study is preliminary but shows a correlation between altering the microbiome and  changes in the brain that should be further explored,” said lead author Martin Blaser, director of the Center for Advanced Biotechnology and Medicine at Rutgers.

In the study, mice were exposed to low-dose penicillin in utero or immediately after birth. Researchers found that, compared to the unexposed controls, mice given penicillin had large changes in their intestinal microbiota, with altered gene expression in the frontal cortex and amygdala. These two key brain areas are responsible for the development of memory as well as fear and stress responses.

Increasing evidence links conditions in the intestine to the brain in the ‘gut-brain axis‘. If this pathway is disturbed, it can lead to permanent altering of the brain’s structure and function and possibly lead to neuropsychiatric or neurodegenerative disorders in later childhood or adulthood.

“Early life is a critical period for neurodevelopment,” Blaser said. “In recent decades, there has been a rise in the incidence of childhood neurodevelopmental disorders, including autism spectrum disorder, attention deficit/hyperactivity disorder and learning disabilities. Although increased awareness and diagnosis are likely contributing factors, disruptions in cerebral gene expression early in development also could be responsible.”

Whether it is antibiotics directly affecting brain development or if molecules from the microbiome travelling to the brain, disturbing gene activity and causing cognitive deficits needs to be determined by future studies.

Source: Rutgers University-New Brunswick

Categories : AntibioticsTags :

Holding off on Antibiotics is Safe and Effective for Patients

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According to an analysis published in BMJ Today, delayed antibiotic prescribing is a safe and effective strategy for most patients with respiratory tract infections.

Delayed antibiotic prescribing—also known as ‘just in case prescribing’—is when patients agree to see whether symptoms settle before collecting a prescription, in order to help reduce antibiotic use.

Delayed prescribing was shown to be associated with a similar duration of symptoms as no antibiotic prescribing and is not likely to lead to poorer symptom control than immediate antibiotic prescribing. In children with immediate antibiotics a slight benefit was seen but this was not judged important enough to justify immediate antibiotic prescribing.

Respiratory tract infections affect the sinuses, throat, airways or lungs and include conditions such as the common cold, sore throat, cough and ear infection. While most improve without treatment, antibiotics are still widely being prescribed for these conditions.

It has been suggested in various clinical trials that delayed antibiotic prescribing for respiratory tract infections is probably safe and effective for most patients, but they were unable to examine different groups of patients or complications.

To address this, an international research team set out to assess the effect of delayed antibiotic prescribing on symptoms for patients with respiratory tract infections in the community.

They used individual patient data on a total of 55 682 patients from nine randomised controlled trials and four observational studies to compare average symptom severity between delayed versus no antibiotic prescribing, and delayed versus immediate antibiotic prescribing.

Most of the studies took place in primary care settings with the average age of study participants ranging from 2.7 to 51.7 years.

The researchers accounted for factors including age, sex, previous duration of illness, severity of symptoms, smoking status and underlying conditions. Average symptom severity was measured two to four days after initial consultation on a seven point scale (ranging from normal to as bad as could be).

The researchers found no difference in symptom severity for delayed versus immediate antibiotics or delayed versus no antibiotics.

Symptom duration was slightly longer in those given delayed versus immediate antibiotics (11.4 v 10.9 days), but was similar for delayed versus no antibiotics.

Complications resulting in hospital admission or death were lower with delayed versus no antibiotics and delayed versus immediate antibiotics, but neither result was statistically significant.

Re-consultation rates were significantly reduced and an increase in patient satisfaction were found for delayed versus no antibiotics, but not for delayed versus immediate antibiotics.

Children under 5 years of age showed slightly more severe symptoms with delayed antibiotics than with immediate antibiotics, but this was not considered to be clinically meaningful, and this was not seen in older age groups.

 hey concluded that delayed antibiotic prescribing “appears to be a safe and effective strategy for most patients, including those in higher risk subgroups.”

This was a large, detailed analysis accounting for differences in study design and quality to reduce bias. The researchers nevertheless pointed out some limitations, being unable to exclude the possibility that other unmeasured factors may have affected their results.

Source: Medical Xpress

Journal information: Beth Stuart et al, Delayed antibiotic prescribing for respiratory tract infections: individual patient data meta-analysis, BMJ (2021). DOI: 10.1136/bmj.n808

Categories : AntibioticsTags :

WHO Says New Antibiotic Treatments are Falling Behind

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The development projects of new antibiotic treatments are falling behind, despite increasing awareness of the antibiotic resistance threat, according to a recently released report by the World Health Organization. 

The WHO revealed that none of the 43 antibiotics that are currently in clinical development sufficiently address the problem of drug resistance in the world’s most dangerous bacteria.

Dr Hanan Balkhy ,Assistant Director General on AMR, WHO said that, “The persistent failure to develop, manufacture, and distribute effective new antibiotics is further fueling the impact of antimicrobial resistance (AMR) and threatens our ability to successfully treat bacterial infections.”

All of the new antibiotics released onto the market in the past few decades have been variations of those developed in the 1980s.

The impact of AMR is most severely felt in resource-constrained settings and in vulnerable populations such young children. Bacterial pneumonia and bloodstream infections are some of the major causes of childhood mortality under age 5, and about 30% of neonates with sepsis die due to bacterial infections resistant to multiple first-line antibiotics.

WHO puts out its Antibacterial Pipeline Report every year, reviewing antibiotics under development. The report evaluates the potential of the candidates to address the most threatening drug-resistant bacteria outlined in the WHO Bacterial Priority Pathogens List (WHO PPL). Since it began in 2017, this list, which includes 13 priority drug-resistant bacteria, has informed and guided priority areas for research and development.

The 2020 report paints a picture of an almost stalled pipeline with only few antibiotics in recent years receiving regulatory approval. Most of these agents in development have little extra clinical benefit over current ones, with 82% of recently approved antibiotics being derivatives of previous  ones with well-established drug-resistance, and drug resistance to these new ones is expected to emerge rapidly.

The review concludes that “overall, the clinical pipeline and recently approved antibiotics are insufficient to tackle the challenge of increasing emergence and spread of antimicrobial resistance”.

Speeding up development requires innovative approaches. For the first time. the 2020 WHO pipeline report includes a comprehensive overview of non-traditional antibacterial medicines, detailing 27 antibacterial agents in the pipeline. These range from antibodies to bacteriophages and therapies that boost the immune response and weaken bacterial effects.

The report notes that there are some promising products in different stages of development. However, only a fraction of these will ever make it to the market due to the economic and inherent scientific challenges in the drug development process. This, along with the small return on investment from successful antibiotic products, has limited the interest of major private investors and most large pharmaceutical companies.

Only a fraction of the promising products in the pipeline will make it to market because of financial and scientific obstacles in the development process. 

The preclinical and clinical pipelines continue to be driven by small- and medium-sized companies, which often struggle to finance their products through clinical trials and approval.

The COVID pandemic has deepened the global understanding of the health and economic implications of uncontrolled disease, as well as funding gaps, including investments in R&D of antimicrobial medicines and vaccines, while also demonstrating that much can be achieved with political will and sufficient funding.

“Opportunities emerging from the COVID-19 pandemic must be seized to bring to the forefront the needs for sustainable investments in R&D of new and effective antibiotics,” said Haileyesus Getahun, Director of AMR Global Coordination at WHO. “Antibiotics present the Achilles heel for universal health coverage and our global health security. We need a global sustained effort including mechanisms for pooled funding and new and additional investments to meet the magnitude of the AMR threat.”

To address funding challenges in antibiotics development, WHO partnered with the Drugs for Neglected Diseases intitive (DNDi) to set up the Global Antibiotic R&D Partnership (GARDP) to develop promising treatments.

In addition, the WHO has been working closely with other non-profit funding partners such as the CARB-X to “push” and accelerate antibacterial research. Another important new initiative is the AMR Action Fund, a partnership by the European Investment Bank. pharmaceutical companies and philanthropies.

Source: News-Medical.Net

Categories : Medical Research & Technology New Compounds and TreatmentsTags :

Combination Nanoparticle Therapy Shows Promise as Antiviral

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Researchers have developed a new nanoparticle combination as a broad-spectrum anti-RNA virus treatment. 

The results of their study have been published on the bioRxiv preprint server. Note that as a preprint, this paper has not yet been peer reviewed.
Non-specific antivirals offer a number of attractive advantages. Their broad spectrum activity suppresses mutations, and would they also readily be at hand for future outbreaks. Nanoparticles are one possibility, with reduced toxicity.

Silver nanoparticles (AgNPs) are well-established as antibacterial and antiviral agents, and are the subject of many exotic biomedical applications. The mechanism of AgNPs is thought to be through physiochemical destruction of the microbial surface, with internal disruption from free Ag+ ions and reactive oxide species. Graphene oxide (GO) also has anti microbial properties. With its high surface area, GO also acts as a drug carrier.

The researchers produced seven different material combinations using three different methods: reduction with silver salt, direct addition of Ag nanospheres, and direct addition of Ag nanospheres to thiolised graphene.
To test the materials against seasonal-type infections as well as the kind of virus that could be expected from a future pandemic, the researchers tested the nanoparticles with influenza A virus (IAV) and human coronavirus (HCoV) OC43. IAV is an enveloped virus of the orthomyxovirus family with a segmented single-stranded RNA genome; it causes flu pandemics. HCoV-OC43 is an enveloped betacoronavirus with a single-stranded RNA genome associated with the common cold in humans.

Two of the GO-AgNP materials showed rapid, potent antiviral activity in solution against the viruses. The remaining five materials possessed a range of modest to no antiviral effects against IAV, the researchers reported. They observed a synergistic effect between the AgNPs and GO, with mechanism of action possibly being rapid disruption of the viral envelope. With high levels of antiviral agents, the combination of AgNPs with GO was found to show greater antiviral performance and lower toxicity.

“Our finding that graphene oxide/silver nanoparticle ink can rapidly prevent in vitro infection with two different viruses is exciting, and suggests that the ink has the potential to be used in a variety of applications to help reduce the spread of viruses in the environment,” said co-author Dr Meredith J Crane.

Source: News-Medical.Net

Journal information: Graphene oxide/silver nanoparticle ink formulations rapidly inhibit influenza A virus and OC43 coronavirus infection in vitro, Meredith J. Crane, Stephen Devine, Amanda M. Jamieson, bioRxiv 2021.02.25.43

Categories : Diseases, Syndromes and ConditionsTags :

Bacteria in Cystic Fibrosis Use Slimy Shield to Ward off Drugs

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Research has revealed that a common bacteria found in the lungs of those with cystic fibrosis produces a slime that acts as a defence against a variety of therapeutic drugs.

Dr Laura Jennings, a research assistant professor in UM’s Division of Biological Sciences and an affiliate with the University’s Center for Translational Medicine, headed the research.

A life threatening-condition caused by a genetic mutation, cystic fibrosis causes persistent lung infections and gradually reduces a person’s breathing capacity. A common strain of bacteria, Pseudomonas aeruginosa, often thrives in the lungs of people with cystic fibrosis,  and when a P. aeruginosa infection is established, it can be extremely hard to remove.
The research showed that stubborn bacteria dwelling in the lungs of cystic fibrosis patients produce a carbohydrate slime, which both shields them against antibiotics and also mucus-reducing drugs.

“We found the first direct evidence that these carbohydrates are produced at the sites of infection,” Dr Jennings said. “We showed that one of the carbohydrates, called Pel, sticks to extracellular DNA, which is abundant in the thick mucus secretions prominent in cystic fibrosis lungs.

“This interaction makes a slimy protective layer around the bacteria, making them harder to kill,” she said. “As such, it reduces the pathogen’s susceptibility to antibiotics and drugs aimed at reducing the thickness of airway mucus by digesting DNA.”

She explained that the research supports a theory that these carbohydrates also support the aggregation of these bacteria in the lungs of cystic fibrosis patients.

“This is important because we know that physically breaking up bacterial aggregates can restore bacterial susceptibility to killing with antibiotics and cells of the immune system,” Jennings said. “Therefore, understanding the mechanisms that promote bacterial aggregation may facilitate new therapeutic approaches aimed at digesting the carbohydrates holding bacterial cells together.”

Source: Medical Xpress

Journal information: Laura K. Jennings et al. Pseudomonas aeruginosa aggregates in cystic fibrosis sputum produce exopolysaccharides that likely impede current therapies, Cell Reports (2021). DOI: 10.1016/j.celrep.2021.108782

Categories : AntibioticsTags :

Single Water Molecule Is the Key to Macrolide Resistance

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High resolution molecular structures produced by researchers at the University of Illinois Chicago show that the effectiveness of the macrolides class of antibiotics – and bacterial resistance to it – depends on interaction with a single water molecule. 

Macrolides have a broad spectrum of use against most gram-positive bacteria and are a widely used treatment  for a variety of infections. Clarithromycin, for example, is used as a mainstay treatment for respiratory infections. Due to antibiotic overuse, antibiotic resistance has emerged Macrolides interrupt protein biosynthesis in the ribosomes of pathogenic bacteria, and are one of the most successful classes of antibiotics to use this mechanism of action. The macrolides accomplish this by entering the cell and binding to the bacteria’s ribosomes, preventing them from manufacturing and releasing new proteins. As a result of the halt in protein synthesis, the bacteria can no longer grow or replicate. However, mutations came about that rendered the bacteria resistant.

Seeking to understand how the bacteria came about their resistance, the researchers learned how to capture images of the ribosome and the macrolide invading it. The researchers discovered that precisely one water molecule was required for the antibiotic to bind to the ribosome.

Corresponding author Yury Polikanov, associate professor of biological sciences at UIC, said: “We compared the hi-res structures of the ribosomes from sensitive and resistant bacteria and noticed that a water molecule that is needed for the tight antibiotic binding was not present in the ribosomes from the drug-resistant bugs. In the ribosomes from the drug-resistant bacteria, there was simply no room for this water molecule.”

The mutation that conferred macrolide resistance adds a pair of methyl groups to where the macrolide molecule normally binds to the ribosome, and the water molecule instead disrupts the binding.  

“We are very much excited by this discovery,” Polikanov said. “Because we now know how exactly macrolide antibiotics interact with their target, the ribosome. This discovery is important because it will inform and facilitate the development of new antibiotics that do not need this water molecule for binding. There is a huge demand for such drugs that are able to kill even those bacteria that became resistant to the currently used drugs.”

Source: News-Medical.Net

Journal information: Svetlov, M.S., Syroegin, E.A., Aleksandrova, E.V. et al. Structure of Erm-modified 70S ribosome reveals the mechanism of macrolide resistance. Nat Chem Biol (2021). https://doi.org/10.1038/s41589-020-00715-0

Categories : Diseases, Syndromes and ConditionsTags :

A Growing Need to Expand Aneurysm Warnings for Fluoroquinolones

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New research suggests that the fluoroquinolone class of antibiotics may increase the risk of aortic aneurysm (AA).

In 2018 the US Food and Drug Administration added warnings for people at risk of aortic disease, based on data from its reporting system plus four epidemiological studies in other countries. According to a study by a team led by Melina Kibbe, MD at the University of North Carolina at Chapel Hill, cases of AA formation or dissection were 7.5 per 10 000 prescription fills for fluoroquinolones at 90 days compared with 4.6 per 10 000 fills for comparison antibiotics.

Fluoroquinolones include ciprofloxacin, gemifloxacin, levofloxacin, moxifloxacin, norfloxacin, and ofloxacin. The FDA had already warned that fluoroquinolones could cause tendon damage and rupture, peripheral nerve damage, mental health disturbance, hypoglycaemic coma and that they are associated with Clostridium difficile infection.

Using a database of health insurance claims for almost 28 million individuals aged 18 to 64,  the researchers searched for associations between fluoroquinolone prescriptions and aneurysms, compared to other antibiotic types.

Fluoroquinolones were associated with excess abdominal AAs (HR 1.31, 95% CI 1.25-1.37) and iliac artery aneurysms (HR 1.60, 95% CI 1.33-1.91), though associations with aortic dissection  or thoracic aortic aneurysm did not reach significance.

“As such, regional differences in the etiology, incidence, and clinical management of aortic disease in the thoracic vs abdominal aorta should be carefully considered,” wrote the researchers.

Adults over 35 also had a greater risk of AA with fluoroquinolones compared to younger cohorts. Limitations of the study included not controlling for the possibility of pre-existing aneurysms, or for the presence of risk factors such as smoking.

However, the researchers believe the results are significant enough to warrant attention. “Almost regardless, this large cohort study of a U.S. population suggests it is time once again to rethink the use of this class of antibiotics for patients with or without aortic disease,” they wrote.

Source: MedPage Today

Journal information: Newton E, Akerman A, Strassle P, Kibbe M. Association of Fluoroquinolone Use With Short-term Risk of Development of Aortic Aneurysm. JAMA Surg. 2021. doi:10.1001/jamasurg.2020.6165

Categories : UncategorizedTags :

Antibiotic Overuse by Children’s Hospitals Contributing to Antibiotic Resistance

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Children’s hospitals may be contributing to antibiotic resistance by overprescription of antibiotics, according to a recent study.

The study, conducted by the University of Alabama at Birmingham (UAB),   found that in 51 children’s hospitals across the United States, rates of antibiotic administration ranged from 22% to 52%. Approximately a quarter of children receiving antibiotics were receiving them incorrectly. This adds to a growing body of evidence that points to antibiotics overuse and misuse by children’s hospitals – which ought to know better.Study co-author, Dr Jason Newland said, “There’s no doubt: We’ve seen some extra use of antibiotics, The impact of the pandemic on antibiotic use will be significant.

“The study’s numbers are likely an underestimate since the research involved 32 children’s hospitals already working together on proper antibiotic use. Newland said the US’ more than 250 children’s hospitals need to improve. Even though COVID fears have reduced the numbers of children’s hospital visits, antibiotics are still being prescribed via telemedicine.

“I hear a lot about antibiotic use for the ‘just in case’ scenarios,” said Dr Joshua Watson, at Nationwide Children’s Hospital in Ohio. “We underestimate the downsides.”

Dr Shannon Ross, an associate professor of paediatrics and microbiology at UAB, said that not all doctors have been taught the correct use of antibiotics. Regarding this overuse, she said, “Many of us don’t realize we’re doing it. It’s sort of not knowing what you’re doing until someone tells you.”
Unnecessary antibiotic use is a problem, and the pandemic “has thrown a little bit of gas on the fire,” said Dr Mark Schleiss, a paediatrics professor at the University of Minnesota Medical School.

“It’s irresponsible,” said Christina Fuhrman, who almost lost her infant daughter to a Clostridium difficile infection, and who now advocates for correct antibiotic use. Along with parents begging for antibiotics in paediatricians’ offices, the situation is “creating a monster.”
Many studies have attested to the rise of C. diff in children, which causes gastrointestinal problems. A 2017 study found that cases of a certain multidrug-resistant Enterobacteriaceae type rose 700% in American children in just eight years. And a steady stream of research points to the stubborn prevalence in kids of the better-known MRSA, or methicillin-resistant Staphylococcus aureus.

“It’s getting more and more worrisome,” said Ross. “We have had patients we have not been able to treat because we’ve had no antibiotics available.”

Source: News-Medical.Net

Journal information: Tribble A, Lee B, Flett K et al. Appropriateness of Antibiotic Prescribing in United States Children’s Hospitals: A National Point Prevalence Survey. Clinical Infectious Diseases. 2020;71(8):e226-e234. doi:10.1093/cid/ciaa036