Artificial nose can quickly sniff out bacterial infections

A researcher at the University of Illinois has created a cheap, disposable "nose" that can correctly sniff out bacterial infections in only a few hours. Right now, you want to know if you have a bacterial infection, you need to supply a blood sample, then wait about 24 to 48 hours--then, another day to see what strain of bacteria you have crawling around inside you. And that's pretty much how they've done it for a century or so.

"The major problem with the clinical blood culturing is that it takes too long," researcher Ken Suslick said in a news release. "In 72 hours they may have diagnosed the problem, but the patient may already have died of sepsis."

Suslick decided to focus his research on a seemingly simpler way to detect types of bacterial infections: smell. Each species of bacteria produces its own unique blend of gases, and even differing strains of the same species will have an aromatic "fingerprint." Experienced microbiologists can take a whiff and identify the bacteria.

Suslick modeled his new device on previous work in sensing toxins in the air. "Our approach to this problem has been to think of bacteria as simply micron-sized chemical factories whose exhaust is not regulated by the EPA," Suslick said. "Our technology is now well-proven for detecting and distinguishing among different chemical odorants, so applying it to bacteria was not much of a stretch."

The researchers placed a colorimetric sensor array in a Petri dish for culturing bacteria and scanned it with an ordinary flatbed photo scanner kept inside a lab incubator. The dots changed color as they reacted with gases the bacteria produce. The researchers tested their array on 10 common infectious bacteria and the color changes showed what kind of bacteria was growing and even if they are antibiotic resistant--very useful for bacteria such as the hard-to-kill methicillin-resistant Staphylococcus aureus (MRSA), which can run rampant in jails and hospitals.

Next, they'll try something that works better than Petri dishes, such as vials of liquid growth medium. Suslick co-founded a device company called iSense, which is commercializing the technology.

- read the release from the University of Illinois
- and the abstract in the Journal of the American Chemical Society