Predominance of multidrug-resistant bacteria with high resistance to empiric antibiotics in diabetic foot ulcers: a cross-sectional study

Why This Matters for People With Diabetes

For many people living with diabetes, a small sore on the foot can quietly turn into a stubborn wound that refuses to heal. This study from Malaysia shows that these foot ulcers are often packed with bacteria that no longer respond to many commonly used antibiotics. Understanding which germs are present, and which medicines still work, is crucial to avoid long hospital stays, serious infections, and even amputation.

Stubborn Wounds in a Growing Diabetes Epidemic

Diabetes is rising worldwide, and with it comes a higher risk of foot ulcers. Nerve damage and poor blood flow mean people may not feel injuries on their feet, and those wounds heal slowly. About one in three people with diabetes may develop a foot ulcer during their lifetime, and roughly half of those ulcers become infected. These infections are rarely caused by a single germ; instead, they usually involve mixed communities of bacteria that can be difficult to treat.

Which Germs Live in These Foot Ulcers?

The researchers examined 153 patients with active diabetic foot ulcers at a large hospital in Malaysia. From their wounds, they grew and identified 383 bacterial samples. Most were “Gram-positive” bacteria, especially Staphylococcus aureus and its close relatives called coagulase-negative staphylococci. Several types of “Gram-negative” bacteria were also common, including Pseudomonas aeruginosa and Klebsiella pneumoniae. Many patients had more than one kind of bacterium in the same wound, reflecting the complex mix of microbes that thrive in these warm, moist, hard-to-heal ulcers.

Hidden Bacterial Cities That Shield Against Drugs

To understand why the infections were so hard to treat, the team also looked at whether these bacteria could form biofilms—slimy layers where microbes stick together and to the wound surface. In this state, they behave more like a protected community than as free-floating cells. About 60% of the patients had bacteria that could build biofilms. These were especially common in more advanced ulcers. Staphylococcus aureus and coagulase-negative staphylococci were the leading biofilm builders, but several Gram-negative species could form them too. Biofilms are important because they can make bacteria up to hundreds of times harder to kill with antibiotics.

Antibiotics Losing Ground

The most alarming finding was how resistant these bacteria were to medicines doctors usually choose first. The study tested 21 antibiotics from 10 different families. Over 60% of the Gram-positive bacteria and a striking 95% of the Gram-negative bacteria were resistant to multiple drug types at once, a situation known as multidrug resistance. On average, the Gram-positive germs resisted about 9 out of the 21 antibiotics tested, while the Gram-negative ones resisted 11 or more. Many strains were no longer stopped by widely used penicillin-like drugs that are meant to be the safest and most accessible options. In contrast, some stronger agents—such as certain “reserve” antibiotics that should be saved for the most serious cases—remained effective but are not meant for routine use.

Rethinking Treatment Choices

To help guide better prescribing, the authors grouped antibiotics according to the World Health Organization’s AWaRe system, which divides drugs into Access, Watch, and Reserve categories. They showed that many Access drugs, usually recommended as first-line choices for diabetic foot infections, now have high failure rates against local bacteria. A few options, like certain aminoglycosides and one powerful beta-lactam, still worked well, but some of these belong to the Reserve group and should be used sparingly to avoid driving resistance even higher.

What This Means for Patients and Doctors

In plain terms, this study reveals that many bacteria in diabetic foot ulcers in Malaysia shrug off the antibiotics that are most often prescribed. Because of this, doctors cannot rely on guesswork when choosing treatments. Instead, regular testing of wound samples, careful tracking of local resistance patterns, and strict rules on when to use stronger drugs are all needed. For patients, it underlines the importance of early foot care, regular check-ups, and taking antibiotics exactly as prescribed. Together, these steps can help preserve the few medicines that still work and reduce the chances that a small sore will lead to a life-changing amputation.

Citation: Shoaib, N.N.M., Chitra, E., Ong, J.R. et al. Predominance of multidrug-resistant bacteria with high resistance to empiric antibiotics in diabetic foot ulcers: a cross-sectional study. Sci Rep 16, 13043 (2026). https://doi.org/10.1038/s41598-026-42418-x

Keywords: diabetic foot ulcers, antibiotic resistance, multidrug-resistant bacteria, biofilms, AWaRe antibiotics