Uropathogen Distribution and Antimicrobial Resistance in Patients With Diabetes, Other Chronic Diseases, and No Comorbidities: A Retrospective Cohort Study

In hospitals and clinics around the world, doctors frequently treat infections of the urinary tract, a common ailment that can range from a mild irritation to a severe, life-threatening condition. When these infections occur, the body's natural defenses are often overwhelmed by bacteria that have found their way into the bladder or kidneys. For decades, medical science has relied on a standard approach to treatment: identifying the specific type of bacteria causing the infection and using antibiotics that are known to kill it. However, a growing global challenge has complicated this process. Many bacteria have evolved to survive the very medicines designed to destroy them, a phenomenon known as antimicrobial resistance. This resistance makes infections harder to treat, often requiring stronger drugs or longer hospital stays.

A major question for doctors is whether a patient's overall health history changes the type of bacteria they are likely to catch or how resistant those bacteria might be. People with long-term health conditions, such as diabetes, often visit the hospital more frequently and may have weaker immune systems, leading some to suspect that their infections are fundamentally different from those of healthy people. Yet, it has been difficult to tell if these differences are caused specifically by diabetes itself, or simply by the fact that these patients are older, spend more time in hospitals, or have other chronic illnesses. Understanding this distinction is vital because it helps doctors choose the right medicine from the start, rather than guessing and hoping for the best.

Researchers at Hisar Intercontinental Hospital in Istanbul, Turkey, set out to untangle these connections by looking at a large collection of urine samples from adults treated between 2021 and 2025. Instead of simply comparing people with diabetes to everyone else, the team divided the patients into three distinct groups to see if the differences were unique to diabetes or common to all chronic illnesses. The first group consisted of patients with diabetes. The second group included patients who had other long-term health problems, such as heart disease or kidney issues, but did not have diabetes. The third group was made up of patients who had no recorded chronic diseases at all. By separating these groups, the researchers hoped to see if the bacteria found in diabetic patients were truly unique or if they simply reflected the general risks of being older and sicker.

The study examined 835 positive urine cultures, which are laboratory tests that confirm the presence of bacteria. The results revealed that the three groups were quite different from one another in their basic characteristics. Patients in the diabetes group were significantly older, with a median age of over 74, compared to those with other chronic diseases who were in their late 60s, and those with no chronic diseases who were in their mid-40s. Perhaps most notably, the diabetes group was far more likely to have had their urine collected through a catheter, a thin tube inserted into the bladder, with 41 percent of their samples coming from this method compared to just 8 percent in the group with no chronic diseases. These factors are important because older age and the use of catheters are known to increase the risk of infection with harder-to-treat bacteria.

When the researchers looked at the types of bacteria causing the infections, they found a clear pattern. In the group with no chronic diseases, the most common culprit was a bacterium called Escherichia coli, which accounted for more than half of all infections. This is the typical bacteria found in most uncomplicated urinary infections. However, as the health burden increased, the proportion of this common bacteria dropped. In the group with other chronic diseases, E. coli made up about 41 percent of infections, and in the diabetes group, it fell to just 32 percent. In its place, the diabetes group showed a higher frequency of other types of bacteria, such as Klebsiella and Pseudomonas, which are often more difficult to treat and are more commonly associated with hospital settings.

The researchers also tested how resistant these bacteria were to various antibiotics. They focused specifically on the E. coli isolates because they were the most numerous. The findings showed that the bacteria from the diabetes group were significantly more resistant to two specific antibiotics: gentamicin and nitrofurantoin. About 35 percent of the E. coli from diabetic patients were resistant to gentamicin, compared to only 13 percent in the other chronic disease group and 9 percent in the group with no chronic diseases. Similarly, resistance to nitrofurantoin was 25 percent in the diabetes group, versus roughly 7 percent and 5 percent in the other two groups. While the bacteria from the diabetes group also showed higher numbers of resistance to other drugs like ceftriaxone and fluoroquinolones, these differences were not large enough to be considered statistically certain, meaning they could have happened by chance.

Crucially, the study authors were careful not to conclude that diabetes itself causes these bacteria to become resistant. They noted that the patients with diabetes were older and had catheters much more often than the other groups. Since age and catheter use are known to increase the risk of resistant infections, the researchers suggested that the higher resistance seen in the diabetes group is likely a result of these factors and the patients' overall exposure to healthcare, rather than the disease of diabetes alone. The study did not have enough information to track how many times patients had been hospitalized or how many antibiotics they had taken in the past, which are key drivers of resistance. Therefore, the data suggests that the profile of infections in diabetic patients is distinct, but this distinction appears to be a marker of a more complex health situation rather than a direct biological effect of high blood sugar.

This research highlights the importance of looking beyond a single diagnosis when treating infections. The findings suggest that doctors should not assume that a patient with diabetes will have a different type of bacteria or a different resistance pattern solely because of their diabetes. Instead, the risk profile is likely shaped by the patient's age, the presence of other chronic conditions, and their history of medical procedures like catheterization. By recognizing that patients with diabetes often fall into a category of "high exposure" due to their age and healthcare needs, medical teams can better interpret local data on which bacteria are common and which antibiotics are still effective. The study ultimately supports a more personalized approach to treatment, where decisions are based on the full picture of a patient's health and history, ensuring that the right medicine is chosen to fight the infection effectively.