Diagnostic bacteria

Bacteria cause illness, poison food, and now, diagnose disease.

Scientists have genetically engineered bacteria to become a fast, effective tool in the diagnostic arsenal of modern medicine. A research team from Montpellier Regional University Hospital in France and Stanford University inserted the equivalent of a computer program into the DNA of bacteria. The programmed bacteria glow when they detect abnormal glucose in the urine of diabetic patients.

In the future this concept may be used to treat various diseases, especially intestinal disease, said lead researcher Jérôme Bonnet. It could also help to identify subtle indicators of diabetic complications.

The bacteria live a long time, even in harsh environments, and multiply quickly, making it simple and inexpensive to create thousands of tests.

The researchers hope their method will work with blood samples as well. “What is needed are detection systems that operate in the body, instead of in excreted urine, which signals trouble too late. Blood levels are more informative in real time,” said Samuel Dagogo-Jack, a professor at the University of Tennessee Health Science Center, to Medical Xpress.

In a separate study, scientists at the University of California, San Diego, and the Massachusetts Institute of Technology programmed bacteria to detect metastatic cancer in mice. Researchers engineered the bacteria to break down a compound that releases a light-emitting molecule when encountering a tumor cell. The molecules then show up in urine.

Further testing is needed before human trials happen, but scientists hope engineered bacteria will one day be a simple method to diagnose a variety of different cancers.

Runners’ risk

Prolonged physical activity can cause bacteria in the gut to escape into the blood, releasing toxins that trigger the immune system and set off a chain of inflammation, according to a study published in Scientific American.

Researchers tested the blood of 17 runners who participated in a 24-hour ultramarathon. The scientists believe lack of blood flow to the intestines and the physical trauma of jarring caused the leakage. Some of the runners’ blood tests actually looked just like those of patients admitted to the hospital for blood poisoning. The researchers said four hours of intense activity is enough to set off the inflammatory process, though athletes can avoid the condition with proper training. The bodies of the most well-trained runners produced anti-inflammatory compounds to attack the immune system’s overreaction. —J.B.

Something fishy

Male fish take on the female function of egg production following exposure to metformin, a drug commonly prescribed to treat diabetes as well as polycystic ovary syndrome. Scientists know male fish that produce eggs—called intersex fish—tend to be particularly prevalent downstream from wastewater treatment plants and have long suspected it was due to hormones from birth control pills. So, researchers at the University of Wisconsin-Milwaukee (UWM) were surprised to find that male fish exposed to doses of metformin similar to those found in wastewater become intersex fish. Metformin, excreted by people taking the drug, is found in freshwater sources worldwide. The researchers found metformin in nearly every water sample from Lake Michigan. “It is the chemical we found in almost every sample and in the highest concentrations compared to other emerging contaminants—even higher than caffeine,” said Rebecca Klaper, a professor at UWM School of Freshwater Sciences. Metformin may become more prevalent as current studies suggest it has anti-aging benefits. —J.B.