A new study has shown that people with diabetes are more likely to develop antibiotic-resistant strains of the bacterial infection Staphylococcus aureus.
Currently there are an estimated 4.95 million human deaths associated with bacterial antimicrobial resistance (AMR) annually. S. 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. Pictured above is a colourised scanning electron micrograph of methicillin-resistant S. aureus (MRSA).
Microbiologists Brian Conlon, PhD, and Lance Thurlow, PhD, at the UNC School of Medicine have just shown that people with diabetes are more likely to develop antibiotic-resistant strains of S. aureus, too. Their results, which have been 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 Conlon, Associate Professor at the Department of Microbiology and 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.”
Diabetes affects the body’s ability to control a type of sugar called glucose, often causing excess glucose to build up in the bloodstream. Staph feeds off these high sugar levels, 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.
The study 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. The findings suggest that controlling blood sugar through insulin use could be key in preventing antibiotic resistance.
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. Recognising how large a role the host plays 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.
- Shook JC, Genito CJ, Darwitz BP, et al. Diabetes potentiates the emergence and expansion of antibiotic resistance. Sci Adv. 2025;11(7):eads1591. doi:10.1126/sciadv.ads1591