Patients who have been prescribed antibiotics in the hospital are more likely to get fungal infections due to disruption of the immune system in the gut.
According to a new study by University of Birmingham and the National Institutes of Health.
Invasive candidiasis, a life-threatening fungal infection, is a major complication for hospitalized patients who receive antibiotics to prevent sepsis and other bacterial infections that spread rapidly in hospitals (such as C. diff). Fungal infections can be more difficult to treat than bacterial infections, but the underlying factors causing these infections are not well understood.
Candidiasis is a fungal infection caused by a yeast (a type of fungus) called candidiasis. Some species of candidiasis can cause infection in people; the most common is Candida albicans. candidiasis normally lives on the skin and in places on the body, such as the mouth, throat, intestines and vagina, without causing problems. candidiasis can cause infections if it gets out of control or gets deep into the body (for example, the bloodstream or internal organs like the kidneys, heart, or brain).
A team from the University Institute of Immunology and Immunotherapy, in collaboration with researchers from the National Institutes of Health, discovered that antibiotics disrupt the immune system in the intestines, which means that fungal infections were poorly controlled in this region. Unexpectedly, the team also discovered that where fungal infections were growing, gut bacteria could also escape, leading to an additional risk of bacterial infection.
The study, published in Host Cell and Microbe, demonstrates the potential of immune-boosting drugs, but the researchers also say their work also highlights how antibiotics can have additional effects on our bodies that affect how we fight infection and disease. This in turn highlights the importance of careful management of available antibiotics.
Lead author Dr Rebecca Drummond said: ‘We knew that antibiotics made fungal infections worse, but the finding that bacterial co-infections can also develop through these interactions in the gut was surprising. These factors can add up to a complicated clinical situation – and by understanding these underlying causes, doctors will be better able to treat these patients effectively.
In the study, the team used mice treated with a broad-spectrum antibiotic cocktail and then infected those animals with Candida albicans, the most common fungus that causes invasive candidiasis in humans. They found that although infected mice had increased mortality, this was caused by infection in the gut rather than the kidneys or other organs.
“These factors can add up to a complicated clinical situation – and by understanding these underlying causes, doctors will be better able to treat these patients effectively.”
— Dr. Rebecca Drummond, Institute of Immunology and Immunotherapy
In a further step, the team identified the parts of the immune system that were missing in the gut after antibiotic treatment, then added them back to the mice using immune-boosting drugs similar to those used in humans. They found that this approach helped reduce the severity of the fungal infection.
The researchers continued the experiment by studying hospital records, where they were able to show that similar co-infections could occur in humans after being treated with antibiotics.
“These results demonstrate the possible consequences of antibiotic use in patients at risk of developing fungal infections,” Dr. Drummond added. “If we limit or change the way we prescribe antibiotics, we can help reduce the number of people who become seriously ill from these additional infections – while tackling the huge and growing problem of antibiotic resistance. “
Reference: “Long-term exposure to antibiotics promotes mortality after systemic fungal infection by causing lymphocyte dysfunction and systemic leakage of commensal bacteria” by Rebecca A. Drummond, Jigar V. Desai, Emily E. Ricotta, Muthulekha Swamydas, Clay Deming, Sean Conlan, Mariam Quinones, Veronika Matei-Rascu, Lozan Sherif, David Lecky, Chyi-Chia R. Lee, Nathaniel M. Green, Nicholas Collins, Adrian M. Zelazny, D. Rebecca Prevots, David Bending, David Withers, Yasmine Belkaid, Julia A Segre and Michail S. Lionakis, May 13, 2022, Cell host and microbe.