Fraunhofer scientists have developed a way to analyse bacteria in a blood sample ten times faster than existing methods. The new technique, which has been demonstrated at the Biotechnica trade show in Hannover this week, takes nine hours to obtain results as opposed to 60-100 hours, which is expected to have a significant impact on the number of lives lost to blood poisoning.
Blood poisoning, or septicaemia, accounts for 60,000 deaths a year in Germany alone, and for patients with the disorder, every second counts.
Doctors who suspect a patient has sepsis start them on broad-spectrum of antibiotics right away, but the antibiotics don’t always have the desired effect – for instance if the bacteria are resistant to the medicines used.
Identifying the pathogens in the lab and investigating their potential resistance allows doctors to determine whether the bacteria are resistant to certain substances, and they can then treat the patient with a targeted antibiotic that reliably kills off the pathogen. However, currently this process routinely takes between 60 and 100 hours. This is time the patient simply doesn’t have – most cases end fatally within around 48 hours.
The new technique developed by the Fraunhofer Institute for Applied Information Technology (FIT) and for Laser Technology (ILT), in collaboration with the university hospital of the city of Aachen, Uniklinikum Aachen, and numerous industry partners, can yield results in just nine hours.
So how are researchers now able to analyse the bacteria in a blood sample up to ten times faster than before?
‘We’ve developed a miniaturised system with a patented optical design,’ revealed Professor Harald Mathis, department head at Fraunhofer FIT.
The first step is to mark the pathogens indicative of septicaemia, so that they glow when exposed to laser light. This then allows the researchers to assess the amount of bacteria present in the blood. In the next stage of the process, the bacteria are separated from the blood and channelled into a series of miniaturised dishes each containing a culture medium that includes a specific antibiotic.
A second optical system complete with the necessary analysis software observes and precisely documents how the bacteria develop. Algorithms then analyse the pictures taken of the bacteria and extrapolate the growth curve, meaning the researchers can see within hours whether the respective medicine is working or whether the bacteria are resistant to it and spreading rapidly.
Essentially, the growth monitor software is able to calculate and predict how bacteria will develop over time. It does so by analysing both the extent of the bacterial growth – which provides a one-to-one indication of the number of bacteria present – and the ratio of living to dead bacteria. In short, this tells researchers which antibiotic will be most effective in killing the bacteria – and help the patient the most.
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