In the case of blood poisoning, the bacteria in the blood must be identified quickly so that life-saving treatment can be started. Empa researchers have developed a “sepsis sensor” A rapid test for sepsis with magnetic nanoparticles that detects bacteria in a short time and identifies those who need antibiotic treatment.
For Qun Ren, every minute counts. An Empa researcher and his team are developing a test system that can quickly detect potentially fatal blood poisoning caused by staphylococcus bacteria. In fact, staphylococcal sepsis kills up to 40% of cases. Bacterial infections can develop as skin infections or colds. Once staphylococci have entered the bloodstream during sepsis, serious problems can occur.
In such cases, bacterial infections should be diagnosed as soon as possible and appropriate antibiotics should be selected for treatment. This is very important for the victims’ chances of survival, since Staphylococcus aureus strains may not be resistant to different antibiotics (see box). Qun Ren, leader of the Biointerfaces laboratory at Empa in Saint-Gall explains,
“If the bacteria from the blood sample have to be developed first for the analysis process, valuable time is lost.” So Qun Ren and his colleague Fei Pan looked to researchers from ETH Zurich for a way to bypass the long interval.
Have sinned in blood
The team developed a method using magnetic nanoparticles that can bind to staphylococci. As a result, specific bacteria can be found through the magnetic field.
In the next step, the effect of antibiotics is analyzed using the chemiluminescence method. If resistant bacteria are present in the test tube, the sample gives off light.
On the other hand, if the bacteria can be killed with antibiotics, the reactor remains dark. “In general, the sepsis test takes about three hours, compared to several days for bacterial culture,” says Fei Pan.
Light fire
Another negative representative of the bacterial kingdom is Pseudomonas aeruginosa. Rod-like bacteria can cause various diseases, including urinary tract infections, for example, through the urinary tract during hospital stay. Such infections can eventually turn into sepsis. In these bacterial infections, many antibiotics are used.
This is where another advantage of magnetic nanoparticles comes in: this method can be used to treat many different types of bacteria as a modular system. Empa researchers have been able to quickly develop a “sepsis sensor” based on magnetic nanoparticles.
In samples containing human urine, the system reliably identified bacterial species and determined antibiotic resistance through chemiluminescence reactions. So far, researchers have evaluated their magnetic nanoparticle application for sepsis and urinary tract infections using laboratory samples.
Qun Ren says, “As a next step, we would like to collaborate with our healthcare partners on sepsis testing. The global antibiotic crisis
Worldwide, the decline in the effectiveness of antibiotics causes more than a million deaths each year. For example, some staphylococci cannot be controlled with common antibiotics because they have developed resistance.
The rate of bacterial resistance is very worrying. Currently, the global resistance of bacteria and antibiotics is described as a “bad disease”. Depending on the country, for example, in Europe more than 30% (Portugal, Italy) and around 1% (Scandinavia) of staphylococci are resistant to different drugs. In Switzerland, the current rate is 4.7%, according to the 2021 statistics from the Federal Office for Food Safety and Veterinary Affairs (FSVO). Pseudomonas aeruginosa bacteria are also resistant to many antibiotics and can cause severe pneumonia, urinary tract infections and sepsis.
Therefore, when diagnosing an infectious disease, the speed and accuracy with which the virus is identified can be important for the survival of those infected.
Source: Swiss Federal Laboratories for Materials Science and Technology (EMPA)
