New research from the University of South Australia shows that the trusted staples of paracetamol and ibuprofen are quietly fuelling one of the world’s biggest health threats: antibiotic resistance.
In the first study of its kind, researchers found that ibuprofen and paracetamol are not only driving antibiotic resistance when used individually but amplifying it when used together.
Assessing the interaction of non-antibiotic medications, the broad-spectrum antibiotic ciprofloxacin, and Escherichia coli, researchers found that ibuprofen and paracetamol significantly increased bacterial mutations, making E. coli highly resistant to the antibiotic.
It’s an important finding that has serious health implications, particularly for people in aged care homes, where multiple medications are regularly administered.
Lead researcher UniSA’s Associate Professor Rietie Venter says the findings raise important questions about the risks of polypharmacy in aged care.
“Antibiotics have long been vital in treating infectious diseases, but their widespread overuse and misuse have driven a global rise in antibiotic-resistant bacteria,” Assoc Prof Venter says.
“This is especially prevalent in residential aged care facilities, where older people are more likely to be prescribed multiple medications – not just antibiotics, but also drugs for pain, sleep, or blood pressure – making it an ideal breeding ground for gut bacteria to become resistant to antibiotics.
“In this study we looked at the effect of non-antibiotic medicines and ciprofloxacin, an antibiotic which is used to treat common skin, gut or urinary tract infections.
“When bacteria were exposed to ciprofloxacin alongside ibuprofen and paracetamol, they developed more genetic mutations than with the antibiotic alone, helping them grow faster and become highly resistant. Worryingly, the bacteria were not only resistant to the antibiotic ciprofloxacin, but increased resistance was also observed to multiple other antibiotics from different classes.
“We also uncovered the genetic mechanisms behind this resistance, with ibuprofen and paracetamol both activating the bacteria’s defences to expel antibiotics and render them less effective.”
Assoc Prof Venter says the study shows how antibiotic resistance is a more complex challenge than previously understood, with common non-antibiotic medications also playing a role.
“Antibiotic resistance isn’t just about antibiotics anymore,” Assoc Prof Venter says.
“This study is a clear reminder that we need to carefully consider the risks of using multiple medications – particularly in aged care where residents are often prescribed a mix of long-term treatments.
“This doesn’t mean we should stop using these medications, but we do need to be more mindful about how they interact with antibiotics – and that includes looking beyond just two-drug combinations.”
The researchers are calling for further studies into drug interactions among anyone on long-term medication treatment regimes so we can gain a greater awareness of how common medications may impact antibiotic effectiveness.
Preterm babies with very low birth weight who received a probiotic alongside antibiotics had fewer multidrug resistant bacteria and a more typical gut microbiome, a new study shows.
The paper published in Nature Communications is the result of a trial testing probiotics among a group of 34 pre-term babies born with a very low birth weight, under 1500g representing around 1-1.5% of babies born around the world. The study sequenced gut bacteria from the babies during the first three weeks after birth.
The collaborative study led by Professor Lindsay Hall and Dr Raymond Kiu from the University of Birmingham found that among babies who received a probiotic treatment of a certain strain including Bifidobacterium alongside antibiotics, levels of typical bacterial strains associated with early-life gut microbiota were at levels typical among full-term babies, reducing both the abundance of antibiotic resistance genes and the number of multi-drug resistant bacteria in the gut.
In the context of the global AMR crisis, this is a major finding, especially for NICUs where preterm infants are especially vulnerable. Probiotics are now used in many neonatal ICUs around the UK, and the WHO have recommended probiotic supplementation in preterm babies. Our paper shows how beneficial this intervention can be for babies born prematurely to help them give their gut a kickstart, and reduce the impact of concerning pathogens taking hold.Professor Lindsay Hall – University of Birmingham
There were lower levels of drug-resistant pathogens including Enterococcus associated with risks of infections and longer hospital stays. Babies who received probiotics also saw higher levels of certain positive bacteria found naturally in the gut.
Among babies who didn’t receive probiotics, analysis of the gut bacteria found that while some differences occurred between those receiving antibiotics or not, both groups saw a dominant microbiome develop that included key bacteria (pathobionts) that can cause health problems including life-threatening infections during the crucial period after birth, as well as in later life.
Professor Lindsay Hall from the University of Birmingham and a group leader at Quadram Institute Bioscience, and senior corresponding author of the study said: “We have already shown that probiotics are highly effective in protecting vulnerable preterm babies from serious infections, and this study now reveals that these probiotics also significantly reduce the presence of antibiotic resistance genes and multidrug-resistant bacteria in the infant gut. Crucially, they seem to do so selectively – targeting resistant strains without disrupting non-resistant strains that might be beneficial.
“In the context of the global AMR crisis, this is a major finding, especially for NICUs where preterm infants are especially vulnerable. Probiotics are now used in many neonatal ICUs around the UK, and the WHO have recommended probiotic supplementation in preterm babies.
“Our paper shows how beneficial this intervention can be for babies born prematurely to help them give their gut a kickstart, and reduce the impact of concerning pathogens taking hold.”
Dr Raymond Kiu from the University of Birmingham, first and co-corresponding author of the paper said: “Sequencing technology has now confirmed that probiotic Bifidobacterium rapidly replicates in the preterm gut during the first three weeks of life. Importantly, this successful colonisation drives the maturation of the gut microbiota and is linked to a noticeable reduction in multi-drug-resistant pathogens – pointing to its pivotal role in improving neonatal health. Our findings also shed light on the complex interactions between antibiotics, probiotics, and horizontal gene transfer (HGT) in shaping the early-life microbiome.
“We believe this research lays the groundwork for future studies exploring the role of probiotics in antimicrobial stewardship and infection control among preterm populations.”
Antibiotics are supposed to wipe out bacteria, yet the drugs can sometimes hand microbes an unexpected advantage.
A new Nature Communications study from Rutgers Health shows that ciprofloxacin, a staple treatment for urinary tract infections, throws Escherichiacoli into an energy crisis that saves many cells from death and speeds the evolution of full‑blown resistance.
“Antibiotics can actually change bacterial metabolism,” said first author Barry Li, a student at Rutgers pursuing a dual doctoral degree for physician–scientists. “We wanted to see what those changes do to the bugs’ chances of survival.”
Li and senior author Jason Yang focused on adenosine triphosphate (ATP), the molecular fuel of cells. When ATP levels crash, cells experience “bioenergetic stress.” To mimic that stress, the team engineered E. coli with genetic drains that constantly burned ATP or its cousin nicotinamide adenine dinucleotide (NADH). Then, they pitted both the engineered strains and normal bacteria against ciprofloxacin.
The results surprised the researchers. The drug and the genetic drains each slashed ATP, but rather than slowing down, the bacteria revved up. Respiration soared, and the cells spewed extra reactive‑oxygen molecules that can damage DNA. That frenzy produced two troubling outcomes.
First, more of the bacteria cells survived.
In time‑kill tests, ten times as many stressed cells survived a lethal ciprofloxacin dose compared with unstressed controls. These hardy stragglers, called persister cells, lie low until the drug is gone and then rebound to launch a new infection.
People have long blamed sluggish metabolism for persister cell formation.
“People expected a slower metabolism to cause less killing,” Li said. “We saw the opposite. The cells ramp up metabolism to refill their energy tanks, and that turns on stress responses that slow the killing.”
Follow‑up experiments traced the protection to the stringent response, a bacterial alarm system that reprograms the cell under stress.
Second, stressed cells mutated faster to evolve antibiotic resistance.
While persisters keep infections smoldering, genetic resistance can render a drug useless outright. The Rutgers group cycled E. coli through escalating ciprofloxacin doses and found that stressed cells reached the resistance threshold four rounds sooner than normal cells. DNA sequencing and classic mutation tests pointed to oxidative damage and error‑prone repair as the culprits.
“The changes in metabolism are making antibiotics work less well and helping bacteria evolve resistance,” said Yang, an assistant professor at the medical school and Chancellor Scholar of microbiology, biochemistry & molecular genetics.
Preliminary measurements show that gentamicin and ampicillin also drain ATP in addition to ciprofloxacin. The stress effect may span very different pathogens, including the pathogen Mycobacterium tuberculosis, which is highly sensitive to ATP shocks.
If so, the discovery casts new light on a global threat. Antibiotic resistance already contributes to 1.27 million deaths a year. Strategies that ignore the metabolic fallout of treatment may be missing a key lever.
The findings suggest several changes for antibiotic development and use.
First, screen candidate antibiotics for unintended energy‑drain side effects. Second, pair existing drugs with anti‑evolution boosters that block the stress pathways or mop up the extra oxygen radicals. Third, reconsider the instinct to blast infections with the highest possible dose. Earlier studies and the new data both hint that extreme concentrations can trigger the very stress that protects bacteria.
“Bacteria turn our attack into a training camp,” Yang said. “If we can cut the power to that camp, we can keep our antibiotics working longer.”
Li and Yang are planning on testing compounds that soothe bioenergetic stress in the hope of turning the microbial energy crisis back into an Achilles’ heel rather than a shield.
A group of infectious disease and public health experts are calling on the Department of Health and Minister Aaron Motsoaledi to reintroduce a national action plan addressing antimicrobial resistance (AMR).
An open letter from over 70 doctors, scientists and public health advisors states that antibiotic resistance is becoming a “growing threat” in the country and poses a threat to universal health coverage through the National Health Insurance.
Latest figures show that over one-million deaths a year worldwide are directly caused by AMR. This number is projected to increase. Nearly five-million people die with an antibiotic-resistant infection. Over the next 25 years, nearly 40-million people are projected to die from AMR.
The open letter also called on the department to reinstate a ministerial advisory committee on AMR or to establish a similar scientific body.
“The lack of a robust scientific advisory body limits the government’s capacity to develop evidence-based policies,” the letter reads. The establishment of a scientific body would “empower the government to make strategic, data-driven decisions to combat this pressing health threat effectively”.
The former Ministerial Advisory Committee was disbanded in November 2023.
Marc Mendelson, an infectious disease specialist at Groote Schuur Hospital who has been outspoken about the threat of AMR for many years, said: “AMR is a current pandemic which is wreaking havoc, is not being attended to properly and not being taken seriously enough in South Africa.”
Mendelson said that there are “more and more people having to be treated for highly resistant bacterial infections in our healthcare system”. AMR leads to an increase in morbidity, mortality, hospital costs, and also has socio-economic consequences, he said. Common medical interventions such as surgery “becomes much riskier” with AMR.
Department of Health spokesperson Foster Mohale said that the department would only comment once the letter was formally presented, which is expected to happen at 5pm on Thursday.
Experts say bacterial infections are responsible for more infant deaths than is generally recognised, and things may get worse as more of the bugs become resistant to commonly used antibiotics. We asked local experts about this growing threat to newborns.
A two-week-old baby is referred to the Red Cross War Memorial Children’s Hospital (RCWMCH) in Cape Town. The infant, who was born prematurely at six months, has come from a nearby neonatal hospital.
She’s developed complications, including a feed intolerance and constant vomiting. On investigation, she is found to have a bowel perforation and a condition called necrotising enterocolitis. Surgeons conclude she needs an operation to repair the perforation. A sample of pus from inside her abdomen is sent to a laboratory to identify any infections. While the tests are being done, the infant is started on second-line antibiotics. The doctors suspect she picked up an infection due to pathogens that may be resistant to first-line antibiotics while in the neonatal hospital.
“But 48 hours later, when the results are available, they may show that the antibiotics we’ve been treating the baby with are not treating the bacteria that have now been detected in the lab,” says Associate Professor James Nuttall, a paediatric infectious diseases sub-specialist at RCWMCH and the University of Cape Town.
“In response to those results, we’d change to a different set of antibiotics to try and target the bacteria that have been detected. In the meantime, the child has deteriorated and requires a second operation. Throughout all the subsequent treatments, we are testing samples for infections she might – and frequently will – acquire along the way.”
From then on, he says it’s a case of trying to keep up with the sequence of infections that the baby might develop. Some of these infections may have originated at the neonatal hospital, while others could have been acquired during her treatment in the Intensive Care Unit (ICU) at RCWMCH, possibly from the operating theatre, intravenous lines, or healthcare workers’ hands.
“This is the kind of scenario we are faced with all the time,” says Nuttall. “The fact is, an infant might come into hospital with one infection and, unfortunately, pick up a bunch of other infections while in the hospital from transmission of pathogens that may be resistant to one or more of the commonly used first- or second-line antibiotics.”
Sitting in a boardroom at the Red Cross Hospital, close to the paediatric wards and clinics in which he treats sick children referred from other hospitals in Cape Town and beyond, Nuttall says there are two possible outcomes for this baby.
“She might turn the corner and respond to the new antibiotics, together with interventions from the surgical doctors and expert management in an ICU. Or she might not respond to the treatment, and die two days later, because of ongoing infection that doesn’t respond to treatment.”
Nuttall is discussing the ongoing issue of rising antibiotic resistance, particularly among neonates, the group most vulnerable to this. He’s responding to Spotlight’s main question: Will the antibiotics used to treat bacterial infections, such as Klebsiella pneumoniae – which have seen hundreds of babies die in hospitals in recent years – keep working? And, how big is the risk of antibiotic resistance to infants?
“The short answer to whether the antibiotics we currently use to treat bacterial infections will keep working is no,” he says.
‘Almost endemic’
In some South African healthcare facilities, especially in the public sector, antibiotic-resistant bacteria have become “almost endemic”, says Professor Shabir Madhi, director of the Wits Vaccines and Infectious Diseases Analytics Unit at University of Witwatersrand (WITS VIDA).
“There are a large number of deaths occurring on an ongoing basis. We still have clusters of outbreaks, but those are underpinned by a really widespread dissemination of these antibiotic-resistant bacteria, and persistently high rates of hospital-acquired infections, especially in the first month of life,” he says. “Despite the best of efforts, we haven’t been able to get on top of this.”
Madhi headed up a study at the Chris Hani Baragwanath Academic Hospital in Soweto in which they used molecular testing to look at evidence of infections in 153 babies who had passed away. The researchers found that infections were the immediate or underlying cause of death in 58% of all the neonatal deaths, including the immediate cause in 70% of neonates with complications of prematurity as the underlying cause.
Overall, 74.4% of 90 infection-related deaths were hospital-acquired, mainly due to multidrug-resistant Acinetobacter baumannii (52.2%), Klebsiella pneumoniae (22.4%), and Staphylococcus aureus (20.9%).
Also asked whether the antibiotics used to treat Klebsiella and other bacterial infections will keep working, Madhi says: “The short answer is that we’ve already run out of antibiotics in the public sector that can treat all of these different bacteria.”
He says that there are two bacteria that are of particular concern in South Africa.
“The one is Klebsiella pneumoniae, which that has become resistant to almost all of the antibiotic classes that are available for use, except perhaps for colistin, (a reserve antibiotic which is seen as a last-resort treatment for multidrug-resistant Gram-negative infections), but even antibiotic resistance to colistin in bacteria is emerging.
“The other big one is Acinetobacter baumannii, which is also a common cause of hospital-acquired infections. Here the bacteria have become resistant to all classes of antibiotics including colistin.”
Madhi says compared to other African countries, South Africa is better equipped to provide high-level care, including intensive care, to prematurely-born babies.
“Consequently, we end up spending a mini fortune to get these very premature children to survive the first few days of life, only for them then to succumb to hospital-acquired infections. Whereas in other settings many of these babies will die in the first few hours of life.”
He adds: “The single leading cause of neonatal mortality in South Africa is antibiotic resistant bacterial infections, but that is underpinned by other conditions which increases the susceptibility of babies to eventually succumb to these hospital-acquired infections.”
In the public sector, Madhi says hospital-acquired infections are a major reason why children are dying. In the private sector, there is more attention on identifying these infections, along with better resources, which helps reduce the problem.
Meanwhile, physicians like Nuttall are put in impossible situations at Red Cross.
“When doing blood tests on an infant to check for infection, you can’t wait for those results. You have to start treatment with what you think is the appropriate treatment. That’s the empirical treatment,” explains Nuttall.
“Then, when you isolate a bacterium and know its resistance profile (or antibiotic susceptibility profile), you must redirect your treatment to what’s known as ‘directed’ or definitive treatment. But there’s now been a time gap of 24 to 72 hours where the infant is on treatment, and you don’t know if it’s the right treatment. That’s a critical issue, because the baby might deteriorate in that time because they’re not on the right treatment,” he says.
He says the choice of empiric antibiotics is becoming more difficult, “as what we previously used as empiric antibiotic treatment is less and less reliable to treat serious infections, particularly in patients who acquire resistant infections in hospital”.
In a position paper, Nuttall and his colleagues write that growing antibiotic resistance is linked to the increased use of “reserve” and “watch” antibiotics. The WHO classifies antibiotics into three groups. Access antibiotics are the common ones used to treat everyday infections in the community. Watch antibiotics are broad-spectrum antibiotics that carry a higher risk of causing resistance, so their use must be carefully monitored and limited. Reserve antibiotics are last-resort treatments for infections caused by multi-drug-resistant bacteria and should only be used when all other options have failed.
‘Totally underestimated’
Following the research described earlier, Madhi says they convened an expert panel, to deliberate on what the causes of death was in children.
Unfortunately, he says, it’s become completely monotonous in that there’s a clear series of events for children born prematurely, who die: They’re admitted to hospital, they usually require ICU, they improve in ICU, and two to three days later, they appear very sick again. “Often you don’t actually identify the bacteria causing the clinical deterioration when you investigate ante-mortem, and you only realise the child actually succumbed to antimicrobial resistant bacterial infections after you’ve done the postmortem sampling”. Postmortem sampling is not done systematically across the country.
“What the post-mortem sampling has unmasked, is that we’ve totally underestimated the contribution of antibiotic-resistant bacteria in relation to causes of neonatal death. If we were to do the same investigations in other facilities, there would be much greater heightened awareness of what is really an unrecognised endemic public health crisis across our healthcare facilities,” says Madhi.
Professor Angela Dramowski, Head of the Clinical Unit: General Paediatrics at Tygerberg Hospital, agrees that outbreaks in low- and middle-income country hospitals, including South Africa are under-reported.
“What we see in the literature and in the headlines of newspapers is the tip of the iceberg. The vast majority of outbreaks in fact are either undetected or unreported. This is almost an invisible problem because a lot of the deaths are currently labelled due to another cause, for example, prematurity.
“This is a crucial public health crisis. We cannot practice modern medicine without effective antibiotics, and, especially for newborns the situation is perilous as we have very few effective treatment options left.”
‘Existential threat’
Though more acute in some areas, the problem is a global one. Marc Mendelson, Professor of Infectious Diseases at the University of Cape Town, describes antibiotic resistance as an existential global health threat.
“If antibiotic resistance is not mitigated, in the next 25 years, 39 million people globally will die of an antibiotic-resistant bacterial infection. That will dwarf HIV, tuberculosis, and malaria,” he says.
“There are bacteria currently causing infections in our hospitals in South Africa that are totally resistant to antibiotics. Those patients would usually die or need extraordinary measures to keep them alive such as amputating a limb to remove the infection in a bone or joint,” Mendelson says.
“People have always assumed if you get sick with a bacterial infection, there will be an antibiotic to treat it. Doctors in and out of hospitals have been too lax in how they prescribe antibiotics. Now we’re paying the price as some bacterial infections are not easily treatable,” he says.
As Dramowski points out, there is a lot of good science confirming the extent of the problem. A systematic review published in The Lancet found that almost 5 million deaths in 2019 were associated with bacterial infections resistant to antibiotics.
“That huge number is more than deaths from HIV and malaria combined,” she says.
Dramowski also points to another review study that found 3 million cases of neonatal sepsis globally each year, with at least 570 000 deaths (likely an underestimate). Over 95% of deaths from neonatal antibiotic resistance occur in low- and middle-income countries (LMICs).
“In a nutshell, in five big studies … they showed that antibiotic resistance to the World Health Organization-recommended antibiotic treatments ranges anywhere between 40 to 70%, so almost half of all babies with severe bacterial infection have resistance to the recommended antibiotic treatment,” she says.
What to do?
To address the major issue of antibiotic resistance in infants, Dramowski stresses the importance of prevention. This includes improving Water, Sanitation, and Hygiene (WASH) as well as Infection Prevention and Control programmes to reduce the spread of antibiotic-resistant bacteria in communities and healthcare facilities. She also stresses the need to prevent pre-term births as much as possible, as hospital admissions carry a high risk of acquiring antibiotic-resistant bacteria and developing infections.
She says increased surveillance of infections in LMICs is also crucial, along with more antibiotic trials to provide better alternatives. Additionally, there is a strong need for responsible antibiotic use (stewardship) to ensure they are only used when necessary, helping to prevent the development of antibiotic resistance.
A challenge in practicing stewardship is the difference in resources between the public and private sectors, says Professor Vindana Chibabhai, Head of the Centre for Healthcare-associated Infections, Antimicrobial Resistance, and Mycology (CHARM) at the National Institute for Communicable Diseases. Expensive antibiotics are more easily accessible in the private sector, while they are often not available in the public sector.
“Antibiotic stewardship is happening all over the country but we need to have a national monitoring system,” she says.
Chibabhai says that private sector clinicians often work independently and are not required to follow stewardship programmes as strictly as those in public sector hospitals. To address antibiotic resistance, she says we need monitoring systems to track the effectiveness of these programmes and provide support to hospitals struggling with them. Even though some hospitals have dedicated pharmacists, microbiologists, and clinicians, Chibabhai says they may need additional help to strengthen their antibiotic stewardship efforts.
‘Lots of lovely paper’
A major issue highlighted by experts is the lack of a clear AMR strategy in South Africa. The last strategy, which covered 2019 to 2024, was not funded, and its impact has not been evaluated.
“We have lots of lovely paper and lots of committed people doing great work but in terms of interventions, none of it is funded,” says Mendelson, who chaired the Ministerial Advisory Committee on Antimicrobial Resistance for the eight years until 2022. “If these interventions were funded, we could save lives.”
Madhi says the consequences of not implementing South Africa’s AMR plan are exactly what we are seeing now. “The problems have become endemic and entrenched in public healthcare facilities and lead to large numbers of unnecessary deaths which could have been prevented if we implemented a proper strategy in place.”
He says the situation now calls for a multi-faceted approach. “It’s not just about the type of antibiotics that should be available but about mitigating the many contributing factors that resulted in these outbreaks. That requires immense investment in terms of resources and expertise.”
Researchers at the University of Oklahoma have made a breakthrough discovery that could potentially revolutionise treatments for antibiotic-resistant infections, cancer and other challenging gram-negative pathogens without relying on precious metals.
Currently, precious metals like platinum and rhodium are used to create synthetic carbohydrates, which are vital components of many approved antibiotics used to combat gram-negative pathogens, including Pseudomonas aeruginosa, a notorious hospital-acquired infection responsible for the deaths of immunocompromised patients. However, these elements require harsh reaction conditions, are expensive to use and are harmful to the environment when mined. In an innovative study published in the journal Nature Communications, an OU team led by Professor Indrajeet Sharma has replaced these precious metals with either blue light or iron, achieving similar results with significantly lower toxicity, reduced costs, and greater appeal for researchers and drug manufacturers.
By using abundant, inexpensive, iron or metal-free, non-toxic blue light, the team can more easily and rapidly synthesize these important carbohydrates. Since most antibiotics rely on a carbohydrate molecule to penetrate the thin, external layer of the gram-negative bacteria, this discovery could transform the way doctors treat multi-drug-resistant pathogens.
“Drug-resistant infections are a major problem and are expected to rise unless something is done,” Sharma said. “By using our methods to make late-stage drug modifications, synthetic carbohydrate-based antibiotics could help treat these infections. Furthermore, since carbohydrates can also increase a drug’s solubility, they can be easily deployed as a pro-drug that a patient can simply take it with water.”
A pro-drug is a medication that it less active when administered and metabolized into its active form. To help drug molecules last longer in the body and work more effectively, Sharma’s team is exploring ways to attach specially designed sugars or unnatural sugar to them. They are using a unique blue light-based method, developed by Surya Pratap Singh, a lead researcher and doctoral student in Dr. Sharma’s lab, that does not require metals.
“If a drug molecule is broken down too quickly, it loses its potency. By replacing an oxygen atom in the carbohydrate molecule with a sulfur one, enzymes in the human body won’t recognise the molecule as a carbohydrate and won’t break it down as quickly,” Sharma said. “These modified compounds, commonly called thiosugars, could be used to more effectively treat infections and diseases like cancer.”
Antibiotic resistance tends to stabilise over time, according to a study published April 3, 2025 in the open-access journal PLOS Pathogens by Sonja Lehtinen from the University of Lausanne, Switzerland, and colleagues.
Antibiotic resistance is a major public health concern, contributing to an estimated 5 million deaths per year. Understanding long-term resistance patterns could help public health researchers to monitor and characterise drug resistance as well as inform the impact of interventions on resistance.
In this study, researchers analysed drug resistance in more than 3 million bacterial samples collected across 30 countries in Europe from 1998 to 2019. Samples encompassed eight bacteria species important to public health, including Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.
They found that while antibiotic resistance initially rises in response to antibiotic use, it does not rise indefinitely. Instead, resistance rates reached an equilibrium over the 20-year period in most species. Antibiotic use contributed to how quickly resistance levels stabilised as well as variability in resistance rates across different countries. But the association between changes in drug resistance and antibiotic use was weak, suggesting that additional, yet unknown, factors are at play.
The study highlights that continued increase in antibiotic resistance is not inevitable and provides new insights to help researchers monitor drug resistance.
Senior author Francois Blanquart notes: “When we looked into the dynamics of antibiotic resistance in many important bacterial pathogens all over Europe and in the last few decades, we often found that resistance frequency initially increases and then stabilises to an intermediate level. The consumption of the antibiotic in the country explained both the speed of initial increase and the level of stabilisation.”
Senior author Sonja Lehtinen summarises: “In this study, we were interested in whether antibiotic resistance frequencies in Europe were systematically increasing over the long-term. Instead, we find a pattern where, after an initial increase, resistance frequencies tend to reach a stable plateau.”
Staphylococcus aureus is a leading cause of antibiotic resistance associated infections and deaths. It is also the most prevalent bacterial infection among those with diabetes mellitus, a chronic condition that affects blood sugar control and reduces the body’s ability to fight infections.
Microbiologists at the UNC School of Medicine have just shown that people with diabetes are more likely to develop antibiotic-resistant strains of Staph, too. Their results, which were published in Science Advances, show how the diabetic microbial environment produces resistant mutations, while hinting at ways antibiotic resistance can be combatted in this patient population.
“We found that antibiotic resistance emerges much more rapidly in diabetic models than in non-diabetic models of disease,” said Brian Conlon, PhD, associate professor of immunology. “This interplay between bacteria and diabetes could be a major driver of the rapid evolution and spread of antibiotic resistance that we are seeing.”
Staph feeds off the high levels of blood glucose in diabetes, allowing it to reproduce more rapidly. The bacterium can also grow without consequence, as diabetes also impairs the immune system’s ability to destroy cells and control infection.
As the numbers of bacteria increase in a diabetic infection, so does the likelihood of resistance. Random mutations appear and some build up resistance to external stressors, like antibiotics. Once a resistant mutant is present in a diabetic infection, it rapidly takes over the population, using the excess glucose to drive its rapid growth.
“Staphylococcus aureus is uniquely suited to take advantage of this diabetic environment,” said Lance Thurlow, PhD, assistant professor of microbiology and immunology. “Once that resistant mutation happens, you have excess glucose and you don’t have the immune system to clear the mutant and it takes over the entire bacterial population in a matter of days.”
Conlon, an expert on antibiotic treatment failure, and Thurlow, an expert on Staph pathogenesis in diabetes, have long been interested in comparing the effectiveness of antibiotics in a model with and without diabetes. Using their connections within the Department of Microbiology and Immunology, the researchers brought their labs together to perform a study with antibiotics in a diabetic mouse model of S. aureus infection.
First, the team prepared a mouse model with bacterial infection in the skin and soft tissue. The mouse models were divided into two groups: one half was given a compound that selectively kills cells in the pancreas, rendering them diabetic, and the other half was not given the compound. Researchers then infected both diabetic and non-diabetic models with S. aureus and treated them with rifampicin, an antibiotic where resistance evolves at a high rate.
After five days of infection, it was time to observe the results.
Conlon and Thurlow were quick to notice that the rifampicin had practically no effect in diabetic models. So, they took some samples to investigate. Researchers were shocked to find that the bacteria had evolved to become resistant to rifampicin, with the infection harboring over a hundred million rifampicin resistant bacteria. There were no rifampicin resistant bacteria in the non-diabetic models.
Their new findings have left Conlon and Thurlow with many questions; however, they are certain that the evolution of antibiotic resistance in people with diabetes could spell trouble for the population at large.
And, even more surprisingly, the mutation had taken over the entire infection in just four days. They next inoculated diabetic and non-diabetic models with Staphylococcus aureus as before, but this time supplemented with a known number of rifampicin resistant bacteria. Again, these bacteria rapidly took over the diabetic infection, but remained as only a sub-population in non-diabetic models after 4 days rifampicin treatment.
Their new findings have left Conlon and Thurlow with many questions; however, they are certain that the evolution of antibiotic resistance in people with diabetes could spell trouble for the population at large. Antibiotic-resistant strains of bacteria spread from person to person in the same ways as other bacteria and viruses do – in the air, on doorknobs, and the food that we eat – which makes preventing these types of infections a major priority.
So, what can be done to prevent it? Well, the Conlon and Thurlow labs showed that reducing blood sugar levels in diabetic models (through administration of insulin) deprived bacteria of their fuel, keeping their numbers at bay, and reducing the chances of antibiotic-resistant mutations from occurring. Their findings suggest that controlling blood sugar through insulin use could be key in preventing antibiotic resistance.
“Resistance and its spread are not only associated with the prescription of drugs, but also the health status of those that are taking antibiotics,” said Conlon. “Controlling blood glucose then becomes really important. When we gave our mice insulin, we were able to bring their blood sugar back to normal and we didn’t get this rapid proliferation of resistant bacteria.”
Now, Conlon and Thurlow are expanding their efforts to study the evolution of resistance in humans (with and without diabetes) and other antibiotic-resistant bacteria of interest, including Enterococcus faecalis, Pseudomonas aeruginosa, and Streptococcus pyogenes. Recognizing how large a role the host plays a role in the evolution of antibiotic resistance, the researchers plan to perform similar studies in patients undergoing chemotherapy and recent transplant recipients to see if those populations are also prone to antibiotic resistant infections.
An international clinical trial has found three new safe and effective drug regimens for tuberculosis that is resistant to rifampin, the most effective of the first-line antibiotics used to treat TB. The research, published in the New England Journal of Medicine, was led by researchers at Harvard Medical School and other members of the endTB project.
The newly identified regimens take advantage of recently discovered drugs to expand the treatment arsenal and give physicians new ways to shorten and personalise treatment, minimise side effects, and treat patients using only pills instead of daily injections. They also offer alternatives in case of drug intolerance, medication shortages or unavailability, or drug resistance, the researchers said.
The endTB trial is one of four recent efforts to use randomised controlled trials to test new, shorter, less toxic regimens for drug-resistant TB. endTB uses two new drugs – bedaquiline and delamanid — which, when brought to market in 2012-2013, were the first new TB medicines developed in nearly 50 years.
To find shorter, injection-free drug combinations for people infected with TB resistant to rifampin, endTB tested five new, all-oral 9-month regimens using the two new drugs in combination with older medications.
A third drug, pretomanid, received emergency authorisation from the FDA for specific use within a regimen against highly drug-resistant TB in 2019, after the endTB clinical trial was underway, and is not included in the regimens used in these trials.
Trial regimens were considered effective if they performed at least as well as the control group, which received a well-performing standard of care composed in accordance with a stringent interpretation of World Health Organization (WHO) recommendations.
The three successful new regimens were successful for between 85 and 90% of patients, compared with 81% success for people in the control group. The control group was treated with longer treatments, which also included the recently discovered medicines.
The trial launched in 2017 and enrolled 754 patients across seven countries: Georgia, India, Kazakhstan, Lesotho, Pakistan, Peru, and South Africa. The goal was to improve treatment for patients with tuberculosis resistant to rifampin. The WHO estimates that some 410 000 people become sick with rifampin-resistant TB each year, including people who have multidrug-resistant TB (MDR-TB). Only 40% are diagnosed and treated, 65%of them successfully.
The study population included children as well as people infected with HIV or hepatitis C, both common in populations with high rates of TB. In another innovation, women who became pregnant while on treatment were included in the endTB trial. These groups are often excluded from clinical trials. In a special report published in August 2024, the WHO added the three noninferior regimens from the endTB trial to the list of treatment options for rifampin-resistant and multidrug-resistant TB (MDR-TB) treatment; the recommendations extend to these neglected groups as well as to pregnant women.
With recent efforts to end patent exclusivity on bedaquiline, two of the endTB regimens and the WHO-recommended pretomanid-containing regimen can all be purchased for less than $500, an access target set by activists more than 10 years ago, which has only just now been achieved. All of these innovations together mean the new shortened, all-oral regimens are available to more people than ever.
Scanning electron micrograph image of cholera bacteria.
Scientists from the National Reference Center for Vibrios and Cholera at the Institut Pasteur, in collaboration with the Centre hospitalier de Mayotte, have revealed the spread of a highly drug-resistant cholera strain from Yemen down through Africa. The study was published in the New England Journal of Medicine.
Cholera is caused by the bacteria Vibrio cholerae and in its most severe forms, it is one of the most rapidly fatal infectious diseases: in the absence of treatment, patients can die within hours. Treatment primarily involves replacing lost water and electrolytes, but antibiotics are also used in addition to rehydration therapy. They are essential in reducing the duration of infection and breaking chains of transmission as quickly as possible.
A strain resistant to ten antibiotics – including azithromycin and ciprofloxacin, two of the three recommended for treating cholera – was identified for the first time in Yemen during the cholera outbreak in 2018-2019[1].
Scientists have now been able to trace the spread of this strain by studying the bacterial genomes. After Yemen, it was identified again in Lebanon in 2022[2], then in Kenya in 2023, and finally in Tanzania and the Comoros Islands – including Mayotte, a French département off the south-east coast of Africa – in 2024. Between March and July 2024, the island of Mayotte was affected by an outbreak of 221 cases caused by this highly drug-resistant strain.
“This study demonstrates the need to strengthen global surveillance of the cholera agent, and especially to determine how it reacts to antibiotics in real time. If the new strain that is currently circulating acquires additional resistance to tetracycline, this would compromise all possible oral antibiotic treatment,” concludes Professor François-Xavier Weill, Head of the Vibrios CNR at the Institut Pasteur and lead author of the study.
