Tag: 19/1/23

Categories : AntibioticsTags :

Researchers Achieve Decolonisation of S. Aureus by Using Probiotics

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Methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Credit: CDC

A clinic trial published in The Lancet Microbe found that a promising approach to that ‘decolonised’ Staphylococcus aureus by using a probiotic instead of antibiotics. The probiotic Bacillus subtilis markedly reduced S. aureus colonisation in trial participants without harming the gut microbiota. 

Staphylococcus aureus are colonising bacteria that often live in the nose, on the body and in the gut but if the skin barrier is broken or the immune system weakened, they can cause serious disease.

Preventing S. aureus infections by “decolonising” the body has gained increased attention as antibiotic resistance has spread, but large amounts of antibiotics are needed, damaging other microbiota and promoting more antibiotic resistance. So far, it appears that only nasal S. aureus colonisation can be targeted with topical antibiotics without doing too much harm, but bacteria quickly can recolonise in the nose from the gut.

Probiotics may be a way to complement or replace antibiotics, of which Bacillus is especially promising because it is administered orally as spores that can survive passage through the stomach and then temporarily grow in the intestine. In prior studies, Dr Otto’s group discovered an S. aureus sensing system needed for S. aureus to grow in the gut. They also found that fengycins, Bacillus lipopeptides that are part peptide and part lipid, stop the S. aureus sensing system from functioning, eliminating the bacteria.

In the clinical trial, conducted in Thailand, the research team tested whether this approach works in people. They enrolled 115 healthy participants, all of whom were colonised naturally with S. aureus. A group of 55 people received B. subtilis probiotic once daily for four weeks; a control group of 60 people received a placebo. After four weeks researchers evaluated the participants’ S. aureus levels in the gut and nose. They found no changes in the control group, but in the probiotic group they observed a 96.8% S. aureus reduction in the stool and a 65.4% reduction in the nose.

“The probiotic we use does not ‘kill’ S. aureus, but it specifically and strongly diminishes its capacity to colonise,” Dr. Otto said. “We think we can target the ‘bad’ S. aureus while leaving the composition of the microbiota intact.”

The researchers also found that levels of S. aureus bacteria in the gut far exceeded S. aureus in the nose, which for decades has been the focus of staph infection prevention research. This finding adds to the potential importance of S. aureus reduction in the gut.

“Intestinal S. aureus colonisation has been evident for decades, but mostly neglected by researchers because it was not a viable target for antibiotics,” Dr Otto said. “Our results suggest a way to safely and effectively reduce the total number of colonising S. aureus and also call for a categorical rethinking of what we learned in textbooks about S. aureus colonisation of the human body.”

The researchers plan to continue their work by testing the probiotic in a larger and longer trial. They note that their approach probably does not work as quickly as antibiotics, but can be used for long periods because the probiotic as used in the clinical trial does not cause harm.

Source: NIH/National Institute of Allergy and Infectious Diseases

Categories : Emergency Medicine Injury & TraumaTags :

Aspirin as Effective as Heparin for Clot Prevention in Bone Fracture Hospitalisation

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Source: Mat Napo on Unsplash

Patients hospitalised with fractures typically receive low-molecular-weight heparin to prevent life-threatening blood clots. A new clinical trial, however, found that inexpensive over-the-counter aspirin is just as effective. The findings, published today in the New England Journal of Medicine, may lead surgeons to change their practice and administer aspirin to these patients.

With more than 12 000 patients, the multi-centre randomised clinical trial is the largest trial ever conducted on orthopaedic trauma patients. This multidisciplinary collaboration between orthopaedic surgeons and trauma surgeons points to the importance of evaluating techniques used to prevent post-surgical complications, like blood clots and infections, through high-quality, head-to-head comparison studies.

“Many patients with fractures will likely strongly prefer to take a daily aspirin over receiving injections after we found that both give them similar outcomes for prevention of the most serious outcomes from blood clots,” said the study’s principal investigator Robert V. O’Toole, MD. “We expect our findings from this large-scale trial to have an important impact on clinical practice that may even alter the standard of care.”

Patients who experience fractures that require surgery are at increased risk of developing blood clots, including life-threatening pulmonary embolisms. Current guidelines recommend prescribing low-molecular-weight heparin (enoxaparin) to prevent these clots, although smaller clinical trials in total joint replacement surgery suggested a potential benefit of aspirin as a less-expensive, widely available option.

The study enrolled 12 211 patients with leg or arm fractures that necessitated surgery or pelvic fractures regardless of the treatment. Half were randomised to 30mg of injectable enoxaparin twice daily. The other half received 81mg of aspirin twice daily. Patients were followed for 90 days to measure health outcomes from the two treatments.

The main finding of the study was that aspirin was “non-inferior,” or no worse than low molecular-weight heparin in preventing death from any cause – 47 patients in the aspirin group died, compared with 45 patients in the heparin group. For other important complications, the researchers also found no differences in pulmonary embolisms between the two groups. The incidence of bleeding complications, infection, wound problems, and other adverse events from the treatments was also similar in both groups.

Of all the outcomes studied, the only potential difference noted was in deep vein thrombosis. This condition was relatively uncommon in both groups as it occurred in 2.5% of patients in the aspirin group, and in 1.7% of patients in the heparin group.

“This relatively small difference was driven by clots lower in the leg, which are thought to be of less clinical significance and often do not require treatment,” said study co-principal investigator Deborah Stein, MD, MPH.

“Many patients don’t like giving themselves injections. It’s not fun in terms of giving the actual injection because it burns, and your stomach tends to bruise more easily compared to aspirin,” said Debra Marvel, a 53-year-old from Columbia, MD, who served as a patient advisor on the study. She received Lovenox (low-molecular-weight heparin) after her legs were crushed in a 2015 pedestrian accident, requiring multiple surgeries at the University of Maryland Shock Trauma Center. “Patients also prefer aspirin because Lovenox can be expensive based on insurance.”

“An estimated one million Americans are hospitalised each year with extremity fractures, and this new finding could help prevent potentially fatal blood clots in these patients using a medication that is cheaper and far easier to administer,” said Mark T. Gladwin, MD, Vice President for Medical Affairs, University of Maryland, Baltimore, and the John Z. and Akiko K. Bowers Distinguished Professor and Dean, University of Maryland School of Medicine. “Given these important results, we can expect the guidelines for the prevention of blood clots to be revised to include the option of aspirin for patients with traumatic bone fractures.”

Source: University of Maryland School of Medicine

Categories : Injury & TraumaTags :

Slower Concussion Recovery for Athletes not All Bad News

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Rugby players
Photo by Olga Guryanova

Athletes who recover more slowly from concussion may be able to return to play with an additional month of recovery beyond the typical recovery time, according to a new study published in the journal Neurology. Slow recovery was defined as taking more than 14 days for symptoms to resolve or taking more than 24 days to return to play, both of which are considered the typical recovery times for about 80% of athletes with concussion.

“Although an athlete may experience a slow or delayed recovery, there is reason to believe recovery is achievable with additional time and injury management,” said study author Thomas W. McAllister, MD, of the Indiana University School of Medicine in Indianapolis. “This is an encouraging message that may help to relieve some of the discouragement that athletes can feel when trying to return to their sport. While some athletes took longer than 24 days to return to play, we found that three-quarters of them were able to return to sports if given just one more month to recover.”

The study looked at 1751 American college athletes diagnosed with a concussion by a team physician. Of Male athletes (63%) participated primarily in football, soccer and basketball. Female athletes (37%) participated primarily in soccer, volleyball and basketball.

Participants were evaluated five times: within six hours after their injury, one to two days later, once free of symptoms, once cleared to return to play and at six months.

Participants reported symptoms daily to medical staff, up to 14 days following injury and then weekly if they had not yet returned to play.

A total of 399 athletes, or 23%, had a slow recovery.

Researchers found that of the athletes who took longer than 24 days to return to play, more than three-fourths, or 78%, were able to return to play within 60 days of injury, and four-fifths, or 83%, were able to return to play within 90 days of injury. Only 11% had not returned to play six months after injury.

For the slow recovery group, the average time for returning to play was 35 days after injury, compared to 13 days in the overall group.

“The results of this study provide helpful information for athletes and medical teams to consider in evaluating expectations and making difficult decisions about medical disqualification and the value of continuing in their sport,” McAllister said.

A limitation of the study is that participants were all collegiate varsity athletes and may not be representative of other age groups or levels of sport, and the results may not apply to other types of mild brain injuries.

Source: American Academy of Neurology

Categories : Ageing Cardiovascular DiseaseTags :

Increasing Age Blunts the Strength of Certain Stroke Risk Factors

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Photo by CDC on Unsplash

Hypertension and diabetes are known risk factors for stroke, but now a new study shows that the amount of risk may decrease as people age. The study is published in Neurology.

“High blood pressure and diabetes are two important risk factors for stroke that can be managed by medication, decreasing a person’s risk,” said study author George Howard, DrPH, of the University of Alabama at Birmingham School of Public Health. “Our findings show that their association with stroke risk may be substantially less at older ages, yet other risk factors do not change with age. These differences in risk factors imply that determining whether a person is at high risk for stroke may differ depending on their age.”

The study involved 28 235 people who had never had a stroke and were followed for 11 years. Risk factors included hypertension, diabetes, smoking, atrial fibrillation, heart disease and left ventricular hypertrophy. Because of the well-known higher stroke risk in Black people (comprising 41% of participants), race was also considered as part of the assessed risk factors, Howard added.

Researchers followed up with participants every six months, confirming strokes by reviewing medical records.

During the study, there were 1405 strokes over 276 074 person-years. Participants were divided into three age groups. The age ranges for those groups varied slightly depending on the data being analysed by researchers. In general, the younger group included participants ages 45–69, the middle group included people in their late 60s to 70s and the older group included people 74 and older.

Researchers found that people with diabetes in the younger age group were approximately twice as likely to have a stroke as people of similar age who did not have diabetes, while people with diabetes in the older age group had an approximately 30% higher risk of having a stroke than people of similar older age who did not have diabetes.

Researchers also found that people with high blood pressure in the younger age group had an 80% higher risk of having stroke than people of similar age without high blood pressure while that risk went down to 50% for people with high blood pressure in the older age group compared to people of similar age without high blood pressure.

With race/ethnicity as a risk factor, Black participants in the younger age group compared to White participants in that group, a difference which decreased in the older age group. For stroke risk factors such as smoking, atrial fibrillation and left ventricular hypertrophy, researchers did not find an age-related change in risk.

“It is important to note that our results do not suggest that treatment of high blood pressure and diabetes becomes unimportant in older age,” said Howard. “Such treatments are still very important for a person’s health. But it also may be wise for doctors to focus on managing risk factors such as atrial fibrillation, smoking and left ventricular hypertrophy as people age.”

Howard also noted that even where the impact of risk factors decreases with age, the total number of people with strokes at older ages may still be larger since overall risk of stroke increases with age. For example, in the younger age group for hypertension, researchers estimate that about 2.0% of normotensive people had a stroke, compared to 3.6% of hypertensive people. In the older age group, about 6.2% of normotensive people had a stroke, compared to 9.3% of hypertensive people.

A limitation of the research was that participants’ risk factors were assessed only once at the start of the study, and it’s possible they may have changed over time.

Source: American Academy of Neurology 

Categories : HIV VaccinesTags :

Trial of New HIV Vaccine Ended Early due to Ineffectiveness

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HIV themed candle
Image by Sergey Mikheev on Unsplash

The investigational HIV ‘Mosaico’ vaccine regimen was safe but did not provide protection against HIV acquisition, an independent data and safety monitoring board (DSMB) has determined. Based on the DSMB’s recommendation, the study will be discontinued. This follows the failure of the similar ‘Imbokodo’ vaccine in sub-Saharan Africa.

The HPX3002/HVTN 706, or ‘Mosaico’ Phase 3 clinical trial began in 2019 and involved 3900 volunteers in Europe, North America and South America. The participants were men who have sex with men (MSM) or transgender people.

The Janssen-developed vaccine was based on ‘mosaic’ immunogens, which are vaccine components featuring elements of multiple HIV subtypes, in order to induce immune responses against a wide variety of global HIV strains. The investigational vaccine regimen consisted of four injections over a year of Ad26.Mos4.HIV, with the mosaic immunogens delivered by a common-cold virus (adenovirus serotype 26, or Ad26). The final two vaccinations were accompanied by a bivalent (two-component) HIV envelope protein formulation, combining clade C gp140 and mosaic gp140 envelope proteins, adjuvanted by aluminium phosphate to boost immune responses. All study vaccinations were completed in October 2022.

In early studies, this vaccine combination induced strong antibody and T-cell responses and protected monkeys exposed to SIV, the simian cousin of HIV. The vaccines however failed to stimulate production of broadly neutralising antibodies (bNAbs) that disable multiple HIV variants, according to aidsmap. In that study, the vaccine conferred a 25.2% effectiveness in protection, but not the 50% necessary for an effective vaccine.

In its scheduled data review, the DSMB determined there were no safety issues with the experimental vaccine regimen. However, the number of HIV infections were equivalent between the vaccine and placebo arms of the study. During the clinical trial, all participants were offered comprehensive HIV prevention tools, including pre-exposure prophylaxis, or PrEP. Study staff ensured that participants who acquired HIV during the trial were promptly referred for medical care and treatment. Participants are being notified of the findings, and further analyses of the study data are planned.

The Mosaico findings track with developments in the Phase 2b ‘Imbokodo’ (HPX2008/HVTN 705) clinical trial, which was testing a similar HIV vaccine regimen in young women in sub-Saharan Africa. A DSMB determined in 2021 that the experimental vaccine regimen in that study was also safe but ineffective in protecting against HIV acquisition.

Source: NIH/National Institute of Allergy and Infectious Diseases