Abstract 

DNA-Chips Seibersdorf. This research centre invented a chip in order to identify bacteria causing diseases in hospitals and in order to detect their resistance against antibiotics.  

The advantage of these chips compared to conventional diagnostic methods is the speed of the whole process - from the blood sample of a patient to the final results.
This new kind of diagnosis only takes a few hours whereas the previous one took 28 hours on an average.
Another important aspect is that the doctors know exactly which kind of bacterium causes the infectious disease. They can also see if there is a resistance against an antibiotic. As a consequence they can treat the patients with the most efficient medication, they need not apply broadband antibiotics and they can avoid long suffering or even death.

The basic part of the chip is a small piece of glass like the one that is used for a microscope. On this so called „carrier“ a robot puts small amounts of short sets of DNA. These „spots“ work like probes for the bacterial DNA.
The DNA of the pathogens is extracted from the blood of the patient with conventional methods. After having been copied via Polymerase Chain Reaction (PCR) it is supplemented with a special fluorescent colour. Then the mix has to be put on the carrier. After it has incubated an hour the chip has to be washed several times. When it is dry it is scanned and you can see if the DNA of the pathogens (if there have been any in the sample) has connected to the probes on the chips.
On the chip there are different probes for each kind of bacteria and the different kinds of antibiotic resistances. So if the patient has a bacterium in his blood, the doctor can see which kind it is because the particular spot on the chip sends out light (fluorescents). In the same way he can find out if these pathogens have a resistance against some antibiotics.

And this makes it very simple to find the right treatment for an infection. Another positive thing is that you can prevent new antibiotic resistances more easily, because you just have to use one antibiotic and you need not try many till you find the right one.
The target for the future is that every hospital can buy a complete package with all the chemicals which are necessary for the different reactions. They also get detailed instructions on how the whole procedure has to be carried out.

Our task in this project was to make a DNA-Chip without any instructions except for the ordinary instructions of the package. We wanted to see if the handling of this new diagnostic method is already fit for use by the public. That means that we were something like „Beta-testers“ for the centre.