Bioanalysis Zone

Novel way to identify pathogens could facilitate targeted treatment


While there are many tests available to find the specific pathogen causing illness, they are time-consuming and it is generally more effective to administer a broad-spectrum drug. That may be about to change, as a team from the University of Pittsburg (PA, USA) have potentially developed a faster alternative.

Describing current diagnostic tests, Xinyu Liu, one of the lead investigators along with Sanford Asher, said: “You can do a swab and culture the bacterium or fungi, but that takes days. You can examine the DNA, but that takes another day or two. It’s a pretty tedious process.” He continued, “So, before the identity of the pathogen can be determined, doctors give infected people a broad-spectrum antibiotic that kills everything.”

To address this issue, the research team has developed a method of identifying pathogens using spectroscopy, with results produced almost immediately.

The group developed a protein hydrogel, which interacts with carbohydrates on the surface of the thrush-causing fungus Candida albicans. Severe C. albicans infections can be life-threatening in immunocompromised patients, such as HIV-positive individuals.

When the hydrogel interacts with C. albicans, photonic crystals within the gel shrink, emitting a specific light signature that can be recognized either using a spectroscope or with the naked eye. The results are near-immediate, providing a diagnosis far quicker than culture methods or DNA analysis.

Liu and Asher explained the significance of their findings: “The broader implications are kind of big. You can imagine that if we try to extend this work, we can use differing antibodies to make hydrogels tailored for specific pathogens such as staph, Escherichia coli, etc. And people living in rural areas or underdeveloped countries might be able to use this method to see if their food or water is contaminated or their kids are infected with deadly pathogens.”

Sources: Pitt researchers developing a novel way to identify pathogens; Cai Z, Kwak DH, Punihaole D et al. A photonic crystal protein hydrogel sensor for Candida albicans. Angew. Chem. Int. Ed. doi: 10.1002/anie.201506205 (2015) (Epub ahead of print).


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