Caption: A schematic shows a smartphone and the diagnostic attachment for antimicrobial susceptibility testing. (Credit: Aydogan Ozcan/UCLA)
Researchers at UCLA have developed an automated diagnostic test reader for antimicrobial resistance using smartphones, which could lead to more routine testing for antimicrobial susceptibility in areas with limited resources.
Antimicrobial-resistant bacteria are becoming more common in bacterial pathogens responsible for high mortality diseases like pneumonia, diarrhea and sepsis and is seen as a severe threat to global public health.
Aydogan Ozcan, Chancellor’s Professor of Electrical Engineering and Bioengineering at the UCLA Henry Samueli School of Engineering and Applied Science, explained the importance of the development.
“This work is extremely important and timely, given that drug-resistant bacteria are increasingly becoming a global threat rendering many of our first-line antibiotics ineffective,” Ozcan said in a statement. “Our new smartphone-based technology can help put laboratory-quality testing into much wider adoption, especially in resource-limited regions.”
One of the challenges in fighting the spread of bacteria has been the limited ability to conduct antimicrobial susceptibility testing in regions that do not have access to labs, testing equipment and trained diagnostic technicians to read the tests.
The new system is a smartphone attachment that can conduct automated antimicrobial susceptibility testing.
The device connects to the smartphone and has a plate that can hold up to 96 wells for testing and an array of LEDs illuminates the sample.
Then the phone’s camera is used to sense small changes in light transmission of each well containing a different dose selected from a panel of antibiotics.
The researchers tested the device using 78 samples from patients, which showed that the mobile-phone-based reader meets the Federal Drug Administration’s defined criteria for laboratory testing with a detection accuracy of 98.2 percent.
According to the researchers, the lowest concentration of antibiotic that prevented the growth of bacteria is used to track drug resistance, a criterion—that is susceptible to antibiotics or resistant to them—to each bacteria and drug combination in order to guide the physician in treatment decisions.
A susceptible result indicates that the organism will not be inhibited by the concentrations of antibiotic achieved with normal dosages used for that drug.
“This mobile reader could eliminate the need for trained diagnosticians to perform antimicrobial susceptibility testing, reduce the cost barrier for routine testing, and assist in tracking of bacterial resistance globally,” Omal Garner, an assistant professor of pathology and laboratory medicine in Health Sciences said in a statement.
Dino Di Carlo, a professor of bioengineering in Engineering, who also collaborated on the study, explained some of the benefits of the smartphone attachment.
“An additional advantage of this technology is the possibility of examining bacterial growth in the presence of a drug at an earlier time point than is currently read, (about 24 hours),” he said in a statement. “This could allow for a more rapid turnaround time of the results to the physician, which might help save lives.”
The other authors of the paper include research engineers Steve Feng and Derek Tseng, members of Ozcan’s lab.
The study was published in Scientific Reports.
