Superbug Impact on the Gut

Monash University researchers have discovered that the devastating bacterial superbug Clostridioides difficile hijacks the human wound healing system in order to cause serious and persistent disease, opening up the development of new therapies to treat the disease.

Clostridioides difficile is the most common hospital-acquired disease and causes persistent and life-threatening gut infections – particularly in elderly and immunocompromised patients.

The infection is very difficult to treat, and often repeatedly reoccurs in patients even after they have been given powerful and debilitating antibiotics for many months. C.difficile is also highly resistant to antibiotics, which greatly complicates treatment.

A team based in the Monash Biomedicine Discovery Institute (BDI) found that C. difficile massively activates a human enzyme called plasminogen in order to destroy gut tissue and to help spread the infection throughout the patient. Ordinarily, plasminogen, and its active form plasmin, is deployed in a highly controlled fashion to break down scar tissue and help wounds heal.

“The results were a huge surprise, and revealed that the severe damage caused to the gut by C.difficile was actually caused by a human enzyme rather than a bacterial toxin,” said study co-leader and infectious disease expert Professor Dena Lyras.

Given their findings, the researchers decided to investigate whether potent antibodies developed by the team and that inhibited the plasminogen / plasmin system could be used to treat the disease.

“We found that an antibody that prevented plasminogen from being activated dramatically stalled the progress of infection and tissue damage,” said first author Dr Milena Awad.

The researchers now aim to commercialise their antibodies in order to treat a range of bacterial and inflammatory diseases.

An advantage of targeting a human protein in an infectious disease is that resistance to the therapy is far less likely to occur.

“The antibody could have broad utility, since the plasminogen / plasmin system is dysregulated in a range of different serious inflammatory and infectious diseases – for example, the plasminogen system most likely is a driver of the devastating lung damage seen in COVID-19,” said study co-leader and structural biologist Professor James Whisstock.

The study was published in the US journal Gastroenterology.

Source: Monash University


Today’s Comic

Organic Chicken Less Likely to Harbor a Dangerous ‘Superbug’

Steven Reinberg wrote . . . . . . . . .

In a finding that suggests organic is best, a new study indicates that chickens raised without antibiotics may have fewer types of antibiotic-resistant salmonella than animals raised at factory farms.

Salmonella is a common infection among poultry, so some large farms feed their chickens antibiotics to prevent the birds from getting sick, and to help them gain weight faster. But this practice can make salmonella resistant to the antibiotics usually used to treat it, the researchers said.

“Chicken and poultry meat samples that were labeled antibiotic-free or organic were half as likely to contain multidrug-resistant salmonella as conventionally raised poultry,” said researcher Nkuchia M’ikanatha. He is lead epidemiologist for antimicrobial resistance response at the Pennsylvania Department of Health, in Harrisburg.

A related study found that almost one-third of meat and poultry were contaminated with antibiotic-resistant forms of the bug, M’ikanatha said.

Genes that make bacteria resistant to recommended antibiotics are a problem because they undermine treatment of severe infections, he added.

“One specific gene found in salmonella isolated from meat and patients makes the bug resistant to the only drug, ceftriaxone, recommended for treating severe salmonellosis in children,” M’ikanatha said.

For the study, M’ikanatha and his colleagues tested 2,500 samples of poultry, ground beef and pork chops purchased from 2015 to 2017 at randomly selected markets in Pennsylvania.

The investigators found that up to 30% of the salmonella they found in the meat samples was resistant to three to five classes of antibiotics. And, over the study period, resistance grew to the antibiotics ceftriaxone, amoxicillin and extended-spectrum cephalosporins.

The researchers also found that meat samples were contaminated by the same bacteria recovered from patients, M’ikanatha said. “Those bugs had genes that make salmonella resistant to recommended antibiotics,” he said.

The studies were funded by the Pennsylvania Department of Health and the U.S. Food and Drug Administration.

Overuse or misuse of antibiotics in humans and animals can lead to antibiotic resistance, increasing the risk that antibiotics will not be effective when needed, M’ikanatha explained.

When doctors decide that antibiotics are needed to treat salmonella, they should run tests to determine whether the bacteria causing the illness is susceptible to the drugs they intend to use, M’ikanatha said.

“Consumers should read product labels and make informed choices based on the evidence about the risk of poultry contamination with drug-resistant salmonella,” he suggested.

The studies were to be presented Thursday at ID Week in Washington, D.C. Such research is considered preliminary until published in a peer-reviewed journal.

Antibiotic-resistant salmonella is increasing in livestock, said Dr. Marc Siegel, a professor of medicine at NYU Langone Medical Center in New York City.

“This is because they raise these animals in squalor — they’re standing in their own poop and easily transmit the bacteria,” he said.

Siegel believes in attacking the problem at its source. “We’ve got to clean up our meat farms and stop feeding everything an antibiotic,” he said. Stopping the use of antibiotics in animals will result in fewer antibiotic-resistant strains, Siegel added.

For consumers, Siegel said that all meats should be cooked thoroughly to kill any bacteria living on it. Also, raw meat should be kept away from other foods because cross-contamination is a danger.

Most cases of salmonella in humans don’t have to be treated. It usually goes away on its own. But for the most severe cases, antibiotics are needed.

Source: HealthDay


Today’s Comic

Superbugs Found in More Than Three-Fourths of U.S. Supermarket Meat

Nearly 80 percent of meat in U.S. supermarkets contains antibiotic-resistant bacteria, according to the Environmental Working Group, a non-profit environmental research organization.

The bacteria — often called “superbugs” — were resistant to at least one of 14 antibiotics tested for in 2015 by the National Antimicrobial Resistance Monitoring System, a federal-public health partnership.

Antibiotic-resistant bacteria were found on 79 percent of ground turkey samples tested; 71 percent of pork chops; 62 percent of ground beef; and 36 percent of chicken breasts, wings and thighs, the findings showed.

Antibiotic resistance is a serious threat to health and food security, according to the World Health Organization.

“Consumers need to know about potential contamination of the meat they eat, so they can be vigilant about food safety, especially when cooking for children, pregnant women, older adults or the immune-compromised,” the report’s author, nutritionist Dawn Undurraga, said in a news release from the organization.

Dr. Gail Hansen, a public health consultant and veterinarian, elaborated on the danger.

“Bacteria transfer their antibiotic-resistance genes to other bacteria they come in contact with in the environment and in the gastrointestinal tract of people and animals, making it very difficult to effectively treat infections,” Hansen said in the news release.

Even though antibiotic resistance is a serious threat to human health, the U.S. government allows meat producers to give antibiotics to healthy animals, the authors of the new report noted.

“When one person or group misuses antibiotics, they cause resistance to the antibiotics to spread, hurting everyone in society,” said Dr. Brad Spellberg, chief medical officer at the Los Angeles County and University of Southern California Medical Center.

“It’s not acceptable for one group of people to profit by hurting everyone else in society,” he added.

Undurraga suggested that consumers can help reduce the amount of antibiotics used in farm animals and slow the spread of drug resistance by choosing organic meat and meat raised without antibiotics.

Along with release of its report, the Environmental Working Group wrote to the U.S. Food and Drug Administration asking the agency to take action.

“The public shouldn’t have to wait until 100 percent of the bacteria found on meat are untreatable with antibiotics before the FDA takes strong action,” Undurraga said. “Now is the time for the FDA to get medically important antibiotics off factory farms.”

Source: Environmental Working Group


Today’s Comic