Seokheun “Sean” Choi, Associate Professor of Electrical and Computer Engineering, has developed a new device that allows antibiotic-resistant bacteria to be tested more quickly. Photo credit: Seokheun “Sean” Choi
The method measures naturally occurring electron transfers.
Bacterial infections have become one of the biggest health problems worldwide, and a recent study shows it COVID-19 Patients have a much greater chance of getting secondary bacterial infections, which significantly increases the death rate.
However, fighting the infections is not an easy task. When antibiotics are prescribed negligently and excessively, it leads to the rapid emergence and spread of antibiotic-resistant genes in bacteria – which is an even bigger problem. According to the Centers for Disease Control and Prevention, 2.8 million antibiotic-resistant infections occur in the US every year, killing more than 35,000 people.
One factor that slows the fight against antibiotic-resistant bacteria is the time it takes to test. The conventional method uses extracted bacteria from a patient and compares laboratory cultures grown with and without antibiotics. However, results can last a day or two, increasing the death rate, length of hospital stay, and the overall cost of care.
Associate Professor Seokheun “Sean” Choi – a faculty member at the Department of Electrical and Computer Engineering, Thomas J. Watson College of Engineering and Applied Sciences at Binghamton University – is exploring a faster way to test bacteria for antibiotic resistance.
“To treat the infections effectively, we need to choose the right antibiotics with the exact dose for the appropriate duration,” he said. “There is a need to develop a method of testing antibiotic susceptibility and provide effective guidelines for treating these infections.”
In the past few years, Choi has developed several projects that combine papertronics with biology, such as one that developed bio-batteries using human sweat.
This new study, titled “A Simple, Inexpensive, and Fast Way to Evaluate the Effectiveness of Antibiotics Against Exoelectrogenic Bacteria,” was published in the November issue of the journal Biosensors and bioelectronics – is based on the same principles as the batteries: bacterial electron transfer, a chemical process that certain microorganisms use for growth, general cell maintenance and information exchange with surrounding microorganisms.
“We are using this biochemical event in a new technique to evaluate the effectiveness of antibiotics against bacteria without monitoring all bacterial growth,” said Choi. “As far as I know, we are the first to demonstrate this technique quickly and with high throughput using paper as the substrate.”
Working with PhD students Yang Gao (who graduated in May and is now a postdoctoral fellow at the University of Texas at Austin), Jihyun Ryu, and Lin Liu, Choi developed a test device that continuously monitors extracellular electron transfer from bacteria.
A medical team would take a sample from a patient, inoculate the bacteria with various antibiotics for a few hours, and then measure the rate of electron transfer. A lower rate would mean the antibiotics are working.
“The hypothesis is that antiviral exposure could inhibit bacterial electron transfer sufficiently that the readout by the device would be sensitive enough to show small fluctuations in electrical output caused by changes in antibiotic effectiveness,” Choi said.
The device could provide antibiotic resistance results in as little as five hours, which would serve as an important diagnostic tool at the treatment site, especially in areas with limited resources.
The prototype – built in part with funding from the National Science Foundation and the US Office of Naval Research – has eight sensors on its paper surface, but these could be expanded to 64 or 96 sensors if medical professionals want to build other tests into the device.
Building on this research, Choi already knows where he and his students want to go next: “Although many bacteria produce energy, some pathogens do not perform extracellular electron transfer and may not be used directly on our platform. However, various chemical compounds can aid electron transfer from non-electricity producing bacteria.
“E. coli, for example, cannot transfer electrons from the inside of the cell to the outside, but with the addition of some chemical compounds they can generate electricity. We are now working on making this technique general for all bacterial cells. ”
Reference: “A Simple, Inexpensive, and Fast Method for Assessing the Effectiveness of Antibiotics Against Exoelectrogenic Bacteria” by Yang Gao, Jihyun Ryu, Lin Liu, and Seokheun Choi, August 20, 2020, Biosensors and bioelectronics.
DOI: 10.1016 / j.bios.2020.112518