Portable System Uses Light to Diagnose Bacterial Infections Faster

PAD system

Caption: PAD system. Left, four optical testing cubes (blue and white) stacked on the electronic base station (white with initials); right, a smartphone with a special app to receive test results transmitted by the electronic base station.
Credit: Park et al. Sci. Adv. 2016

Every year, hundreds of thousands of Americans acquire potentially life-threatening bacterial infections while in the hospital, nursing home, or other health-care settings [1]. Such infections can be caused by a variety of bacteria, which may respond quite differently to different antibiotics. To match a patient with the most appropriate antibiotic therapy, it’s crucial to determine as quickly as possible what type of bacteria is causing his or her infection. In an effort to improve that process, an NIH-funded team is working to develop a point-of-care system and smartphone app aimed at diagnosing bacterial infections in a faster, more cost-effective manner.

The portable new system, described recently in the journal Science Advances, uses a novel light-based method for detecting telltale genetic sequences from bacteria in bodily fluids, such as blood, urine, or drainage from a skin abscess. Testing takes place within small, optical cubes that, when placed on an electronic base station, deliver test results within a couple of hours via a simple readout sent directly to a smartphone [2]. When the system was tested on clinical samples from a small number of hospitalized patients, researchers found that not only did it diagnose bacterial infections about as accurately and more swiftly than current methods, but it was also cheaper. This new system can potentially also be used to test for the presence of antibiotic-resistant bacteria and contamination of medical devices.

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Creative Minds: Bacteria, Gene Swaps, and Human Cancer

Julie Dunning Hotopp

Julie Dunning Hotopp

When Julie Dunning Hotopp was a post-doctoral fellow in the early 2000s, bacteria were known for swapping bits of their DNA with other bacteria, a strategy known as lateral gene transfer. But the offloading of genes from bacteria into multicellular organisms was thought to be rare, with limited evidence that a bacterial genus called Wolbachia, which invades the cells of other organisms and takes up permanent residence, had passed off some of its DNA onto a species of beetle and a parasitic worm. Dunning Hotopp wondered whether lateral gene transfer might be a more common phenomenon than the evidence showed.

She and her colleagues soon discovered that Wolbachia had engaged in widespread lateral gene transfer with eight species of insects and nematode worms, possibly passing on genes and traits to their invertebrate hosts [1]. This important discovery put Dunning Hotopp on a research trail that now has taken a sharp turn toward human cancer and earned her a 2015 NIH Director’s Transformative Research Award. This NIH award supports exceptionally innovative research projects that are inherently risky and untested but have the potential to change fundamental research paradigms in areas such as cancer and throughout the biomedical sciences.

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