New Technology Determines Antibiotic Resistant Bacteria in One Hour

In a world where more and more bacteria are building antibiotic resistance — and most countries have proven to be unprepared for the repercussions — new technology comes with a slew of benefits.

Lead investigator Justin Besant, PhD, and colleagues from the University of Toronto designed a small chip that can detect antibiotic resistance. Not only does this development provide innovative testing to replace traditional methods, but it cuts the wait time for results. It can take 3 days to get feedback on potentially deadly infections, however, the chip does the same in just one hour.

“Guessing can lead to resistance to these broad-spectrum antibiotics, and in the case of serious infections, to much worse outcomes for the patient,” Besant said in a news release.

So how were the researchers able to expedite the testing process by such a substantial amount?

While current devices require a few days for bacteria to reach detectable levels, the chip channels metabolically-active bacteria, according to the research documented in Lab on a Chip. The bacteria flows through microfluidic wells, which have a filter made of a lattice of tiny microbeads at the bottom, and then planted onto the glass chip.

“The bacteria accumulate in the nano-sized well, where they’re trapped with the antibiotic and a signal molecule called resazurin,” the statement explained. “Living bacteria metabolize resazurin into a form called resorufin, changing its electrochemical signature.”

The electrodes in the chip reveal if medication will work on the infection. If the bacteria continue to metabolize resazurin into resorufin then it is antibiotic resistant, however, if it stops then it relays that information as well. The team noted that this is the first time an electrochemical readout is given via increased sample concentration.

“The electronics for our electrochemical readout can easily fit in a very small benchtop instrument, and this is something you could see in a doctor’s office, for example,” Besant said.

In a situation where time is of the essence, this crucial feature has multiple advantages. For one this method provides high concentration levels due to the small space of the chip. In addition, the bacteria does not dwindle into a solution, like other techniques, so detectability levels can continue to increase over time.

“The next step would be to create a device that would allow you to test many different antibiotics at many different concentrations, but we’re not there yet,” Besant concluded.