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S C HW E R P U N K T 24 Ironically, it is the very use of antibiotics in the fight against infectious diseases that is partly responsible for one of the most pressing health problems of the 21st century. Increasingly, pathogens are adapting to the active substances in antibiotics, thereby making some drugs ineffective. Hardly any new antibiotics have been developed over the last 20 years. In Germany, around 500,000 patients a year contract a hospital-acqui- red infection—and 15,000 of them die as a result. Faster and more precise diagnostic methods could lead to more targeted use of antibiotics, thus reducing unnecessary prescriptions. Researchers from the University of Jena, the Leibniz Institute of Photonic Technology (Leibniz-IPHT) and the Center for Sepsis Control and Care (CSCC) offer a solution to this problem. Rapid test shows antibiotic resistance BY SEBASTIAN HOLLSTEIN »All organisms—and especially micro- organisms—adapt to their environ- ment in order to ensure the survival of their species,« asserts Prof. Jürgen Popp. »Resistance to antibiotics can therefore not be prevented—but it can be delayed.« To achieve this, a doctor would have to be in a position to pre- scribe the drug that specifically treats the infection in question. However, up to now it has been usual to tackle a pa- thogen using broad-spectrum antibio- tics, which also kill other bacteria. This encourages many more bacterial strains to develop resistance. If a doctor knew exactly which pathogen was involved, he would be able to prescribe a targeted remedy that only affects the bacterium concerned. However, this usually re- quires elaborate diagnostic procedures, which can take up to 72 hours and hin- der rapid treatment of the illness. »So we need tests that quickly show how a pathogen reacts to an antibiotic,« ex- plains Popp. Popp, who heads the Institute of Phy- sical Chemistry at the University of Jena and leads the Leibniz-IPHT, has developed such a procedure over the last few years, together with colleagues from the CSCC and the InfectoGnostics Research Campus. At the centre of this procedure is a chip of about four square centimetres. On this chip patient sam- ples, such as urine, are brought into contact with antibiotics, which react with the bacteria in the sample. To be able to examine them more closely, die- lectrophoresis is used to concentrate the pathogens on the chip into an area of just a few micrometres. To this end, the surface of the chip carries electrodes, which generate inhomogeneous electric fields when a voltage is applied. In turn, the effect of these fields holds the bac- teria in place at specific points, without damaging them. If the pathogens are