A prototype for rapid diagnosis is being used in hospitals

A new process could greatly speed up the process of identifying resistant pathogens. It is now being tested in the real-life setting.

A so-called minimum viable product (MVP) of Resistell: The device can be used in practice, with the idea to provide feedback for further development.

​The conventional diagnostic methods used to determine the resistance of bacteria to antibiotics are slow. They take at least one to two days to produce results, and as long as a month for some slow-growing pathogens such as the bacterium that causes tuberculosis. Yet patients with serious bacterial infections need to start treatment immediately. In such cases doctors often administer broad-spectrum antibiotics, basically hoping for the best. “This is a big problem because it facilitates the spread of resistance,” says Giovanni Dietler, a researcher working on NRP 72 and Professor of Physics of Living Matter at EPF Lausanne.

A result in hours, not days

A possible solution to this problem has now been put forward by the spin-off “Resistell”, established by Dietler in conjunction with physician Sandor Kasas and microbiologist Danuta Cichocka. The company is developing a new diagnostic method that is considerably faster than previous procedures. It produces the resistance profile of a pathogen within a few hours instead of days. “This makes it possible to select the most effective treatment from the outset,” Dietler says, which not only avoids the untargeted use of antibiotics but can also save lives.

While the current diagnostic standard – known as an antibiogram – measures the inhibitory action of antibiotics on bacterial growth, the new method uses a different principle. It indirectly measures the metabolic activity of living bacteria. The bacteria are applied to a fibre measuring a few thousandths of a millimetre of the kind used in atomic force microscopy. If the bacteria are alive, their metabolic activity makes the fibre vibrate, and this vibration can be measured using a laser and a photodetector. If an antibiotic that kills the bacteria is added, the vibrations stop after about 20 minutes. If the bacteria are resistant, on the other hand, the fibre continues to vibrate. In this way the effect of an antibiotic can be seen directly and in real time.

More hospitals needed for tests

“We have already shown that the new measuring principle works reliably,” says Danuta Cichocka, one of the co-founders of Resistell. In a test with various strains of bacteria and antibiotics, the results were nearly 100% identical with those produced by the traditional antibiogram. But a number of hurdles have to be overcome before the method can be used for clinical diagnosis. There are currently several prototypes of a measuring device, two of which are undergoing testing in a practical hospital setting. They recently went into testing in the microbiological diagnostics laboratory run by Professor Gilbert Greub at Lausanne University Hospital. “Feedback from the real-life setting is very important in helping us to improve and refine the equipment,” Cichocka explains. This is why Resistell is currently looking for additional hospitals – both in Switzerland and other European countries – that are interested in testing the new device. At the end of this year, the company will then start looking for investors to fund clinical testing. They are needed so that the new method can be used for diagnosis in hospitals and laboratories. Danuta Cichocka is convinced that “only if resistance can be diagnosed faster will it be possible to ensure the efficacy of antibiotics in the future”.