Friday, 15 November 2013

Screening for hospital pathogens

A new microfluidic device (for handling small volumes of fluids) has been developed by researchers to screen for hospital pathogens like Pseudomonas aeruginosa.
Pseudomonas aeruginosa is a bacterium common in soil and water; it has also been associated with hospital acquired infections. People with weakened immune systems are at a particular risk, especially from the disease cystic fibrosis (the forming thick layers of mucus in the lungs).
To help the diagnosis of the pathogen, MIT researchers have developed a new microfluidic device that could speed the monitoring of bacterial infections associated with cystic fibrosis and other diseases. The advantage with the device is that it can screen patient samples faster and with greater accuracy.
The microfluidic chip is etched with tiny channels, each resembling an elongated hourglass with a pinched midsection. Researchers injected bacteria through one end of each channel, and observed how bacterial cells travel from one end to the other. The cells were propelled by electrical forces. Depending on the type of bacterial cell, they either passed through the channel's narrow section or were trapped at the opening. By using this method, the researchers could screen which bacteria are pathogens and which are harmless.
To demonstrate the method, the researchers examined ordinary strains of P. aeruginosa, along with mutant strains that were missing certain genes required to make the dangerous pathogens. From their experiments, the researchers found that their device is able to distinguish benign bacterial cells from those that are more likely to be pathogenic.
The study was a collaboration between scientists at Ghent University, Belgium, and the University of Queensland, in Australia. The findings have been published in the journal PLOS One. The paper is called “Dielectrophoresis-Based Discrimination of Bacteria at the Strain Level Based on Their Surface Properties.”

Posted by Tim Sandle