New “Artificial Nose” Can Sniff Out Blood Infections

Researchers have come up with an unexpected way to diagnose and identify the microbes responsible for blood infections. They have developed an “artificial nose” made up of a plastic bottle, small enough to fit in the palm of a hand, filled with nutrient solution for bacteria to grow. Attached to the inside is a chemical sensing array (CSA) with 36 pigment dots. The dots change color in response to signature odor chemicals released by bacteria.

The research team included James Carey, Ph.D., a professor of chemistry at National Kaohsiung University in Taiwan, and Ken Suslick, Ph.D., professor of chemistry at the University of Illinois at Urbana-Champaign.

“We have a solution to a major problem with the blood cultures that hospitals have used for more than 25 years to diagnose patients with blood-borne bacterial infections,” said Carey, who presented a report on the technology at the 246th National Meeting & Exposition of the American Chemical Society. “The current technology involves incubating blood samples in containers for 24 to 48 hours just to see if bacteria are present. It takes another step and 24 hours or more to identify the kind of bacteria in order to select the right antibiotic to treat the patient. By then, the patient may be experiencing organ damage, or may be dead from sepsis.”

The device, according to the researchers, can detect infection within 24 hours, instead of the usual 72 hours. It is estimated that currently 20 to 35 percent of patient diagnosed with sepsis die, in part due to the length of time it takes to reach a diagnosis.

Using the device is simple, Carey said. A blood sample from a patient is injected into the bottle, which goes onto a simple shaker device to agitate the nutrient solution and encourage bacterial growth. Any bacteria present in the blood sample will grow and release a signature odor that changes the colors of pigment dots on the sensor. The test is complete within a day, and the results can be read in a pattern of color changes unique to each strain of bacteria.

Carey said the new device can identify eight of the most common disease-causing bacteria with almost 99 percent accuracy under clinically relevant conditions. Other microbes can cause sepsis, and the scientists are working to expand the test’s capabilities. But Carey said the device could make an impact now in reducing the toll of sepsis, especially in developing countries or other medically underserved areas.

“Our CSA blood culture bottle can be used almost anywhere in the world for a very low cost and minimal training,” Carey noted. “All you need is someone to draw a blood sample, an ordinary shaker, incubator, a desktop scanner and a computer.”

Carey’s research was funded by ChemSensing Inc., Oklahoma City University, the National Kaohsiung University and the National Science Council of Taiwan. This funding builds on prior funding granted to Suslick from Genes, Environment and Health Initiative of the National Institutes of Health.