microfluidic chip
The microfluidic chip allows for optical determination of antibiotic resistance patterns. Courtesy of S. Döring/ Leibniz-IPHT

Rapid Test Helps Administer the Correct Antibiotic

Scientists at the Leibniz-Institute of Photonic Technologies (Leibniz-IPHT), Center for Sepsis Control and Care at the University Hospital Jena and Friedrich Schiller University are working on a faster and cheaper alternative for hitherto time consuming pathogen diagnostics.

Project manager and professor Ute Neugebauer illustrates the advantages of this new approach: "We combine light-based analytical methods with microfluidic sample processing. With our Lab-on-a-Chip system, thus a miniaturised lab, we are able to clearly identify bacterial strains and their resistances, in less than three hours."

Standard practices for the infectious diagnostics require up to 72 hours to allow for a reliable result. This is due to the fact, that the number of pathogens in a patients sample is too small to conduct tests. Analysis is therefore only possible after time-consuming cultivation. Especially in clinical application during treatments of severe infections e.g. a sepsis time is a crucial factor. Physicians are confronted with an alarming dilemma: "Far too often we have to administer broad-spectrum antibiotics blindly because we can neither analyse pathogen nor potential resistances. Therefore, we possibly use a sledge-hammer to crack a nut. A vicious cycle that aides the development of new resistances," explains professor Michael Bauer, director of the Clinic of Anesthesiology and Intensive Care at the University Hospital Jena.

The new method out of Jena provides much faster diagnosis as basis for a decision of a reliable therapy. Ute Neugebauer, who works at Leibniz-IPHT and the University Hospital Jena points to tiny electrodes that are fixed on the surface of a stamp-sized chip: "Electric fields secure bacteria in a very small area". Jena's scientists then apply various antibiotics in different concentrations on the trapped bacteria and examine them with Raman spectroscopy. "This means that we irradiate the pathogens with laser light and evaluate the scattered light spectrum," says Neugebauer of the method.

Professor Jürgen Popp, director of the Leibniz-IPHT and head of the Institute of Physical Chemistry of the Friedrich-Schiller University Jena, explains, "After two hours we can already detect distinct changes in the Raman spectra. Out of these, we can derive whether the strain is resistant or sensible. At the same time we get information on the needed concentration of the antibiotic to constrain bacterial growth. This is an important diagnostic parameter that influences the success of a treatment decidedly." The results of the team of chemists, physicians, and biologists were published in the current edition of the journal Analytical Chemistry.

The combination of fast, light-based diagnostics and a high automation level reduces the time from sampling to result from to date 72 to three and a half hours. "Such a fast procedure could revolutionize diagnostics of infectious diseases," says Prof. Bettina Löffler, director of the Institute of Medical Microbiology at the University Hospital Jena. Currently, researchers work at a platform for the application in hospitals. Another more far-reaching aim is the further development into a rapid test system which will enable general practitioners to identify resistances in a fast and easy way for the first time. 

The research was funded by the European Union, the Federal Ministry for Education and Research, the Free State of Thuringia, and the Carl-Zeiss-Foundation.

Source: Leibniz-Institute of Photonic Technologies

 

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