Clinical Lab Daily News – Rapid sepsis test uses magnetic nanoparticles to detect bacterial pathogens – Microbiology

Rapid sepsis test detects bacterial pathogens using magnetic nanoparticles

Written by the LabMedica Spanish-language editorial team
Updated on August 27, 2023

When dealing with life-threatening blood poisoning caused by staphylococci, rapid identification of the bacteria in the blood is critical to initiating life-saving treatment. This urgency stems from the fact that staphylococcal sepsis kills up to 40% of cases. Infections caused by spherical bacteria may initially present as localized skin disease or pneumonia. However, when staph bacteria infiltrate the bloodstream during sepsis, serious complications can arise. In such critical situations, early identification of pathogens and selection of appropriate antibiotics are crucial.This is especially important because strains from Staphylococcus aureus

They may be resistant to multiple antibiotics. Researchers have now developed a “sepsis sensor” using magnetic nanoparticles that can rapidly detect bacterial pathogens and identify appropriate candidate antibiotics.

Together with colleagues at ETH Zurich (Zurich, Switzerland), researchers at Empa (Diebendorf, Switzerland) looked for a way to avoid the lengthy intermediate step of first cultivating bacteria in blood samples during the diagnostic process. They developed a method using magnetic nanoparticles capable of binding to staphylococci. Therefore, these bacteria can be identified by applying a magnetic field. Subsequently, antibiotic susceptibility was assessed using chemiluminescent techniques. The sample glows if antibiotic-resistant bacteria are present in the sample. Conversely, if the bacteria can be wiped out with antibiotics, the reaction vessel will remain dark.

Image: Magnetic nanoparticles (red) specifically bind spherical bacteria (yellow) (photo courtesy of Empa)

Another problematic bacterial entity is Pseudomonas aeruginosa , a rod-shaped bacterium, is capable of causing a variety of illnesses, including urinary tract infections through urinary catheters during hospitalization. These infections can progress to sepsis, and these pathogens are often resistant to many antibiotics. In this context, magnetic nanoparticles offer the unique advantage of multifunctionality. The method can be customized for different types of bacteria, similar to a modular system. This adaptability allowed the researchers to design a rapid “sepsis sensor” using magnetic nanoparticles. In samples containing synthetic urine, the method reliably identified bacterial species and measured potential antibiotic resistance using chemiluminescent reactions. So far, the researchers have evaluated their magnetic nanoparticle kit for sepsis and urinary tract infections using laboratory samples. In the next phase, the team plans to work with clinical partners to validate the sepsis test by testing patient samples.

“Overall, the sepsis test takes about three hours, while traditional bacterial culture takes several days,” said Empa researcher Fei Pan.

Related Links:
Empa
ETH Zurich