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Friday, 02 August 2019

Bacterial or viral? Accurate diagnosis of infections with a paper-based test

A new immunoassay test to distinguish viral from bacterial infections could help reduce the use of antibiotics and the consequent development of drug-resistant bacteria. This study published in Nanoscale has been carried out by a team of researchers led by Prof. Kimberly Hamad-Schifferli, from the University of Massachusetts, and ICREA prof. Victor F. Puntes, from the ICN2 and the VHIR.

Distinguishing if an infection has viral or bacterial nature is essential for its effective treatment. Unfortunately, the diagnostic is not easy, since most infections show similar non-specific symptoms, such as fever, congestion, headaches and respiratory problems. As a consequence, antibiotics, which are necessary to fight bacterial infections, are often prescribed for viral diseases as well. In these cases, not only are they inefficient, but can also aggravate the health conditions of the patient and ultimately contribute to the development of drug-resistant bacteria.

Researchers at the University of Massachusetts and at the ICN2 have developed an immunoassay test to detect the presence and concentration of the Myxovirus protein A (MxA) in blood, which allows viral vs. bacterial infection diagnosis. This study, which was recently published on Nanoscale and shared by UMass Boston News, was carried out by Dr Lorenzo Russo at the ICN2, who developed his PhD thesis on this project, under the guidance of Prof. Kimberly Hamad-Schifferli, Associate Professor at the Department of Engineering of the University of Massachusetts, and ICREA Prof. Victor F. Puntes, Group Leader at the ICN2 and at the Vall d'Hebron Institut de Recerca (VHIR).

The MxA protein has been observed to be produced when an infection is present in our body. Since its concentration in the blood is much higher for viral infections, MxA can be used as a biomarker to identify the nature of the infection in action. In this research, a paper-based test, which is a paper strip that when put in contact with the biological fluid changes color, was developed and its effectiveness assessed.

It was observed that such test is particularly efficacious for children, because the levels of MxA vary not only with the type of infection, but also with the age of the patient. In order to enhance the sensitivity of the immunoassay for adults, gold and silver nanoparticles that are able to interact with the protein were used. This allows the detection of the MxA thanks to a technique called Surface Enhanced Raman Spectroscopy (SERS).

Applied to the clinical practice, this test could help prevent the prescription of antibiotics when not needed and limit the development of antibiotic-resistant bacteria, which are cause of death for at least 23.000 people only in the US (according to a review published by the Centers for Disease Control and Prevention).


Article Reference: 

Lorenzo Russo, Maria Sánchez-Purrà, Cristina Rodriguez-Quijada, Brianna M. Leonardo, Victor Puntes and Kimberly Hamad-Schifferli, Detection of resistance protein A (MxA) in paperbased immunoassays with surface enhanced Raman spectroscopy with AuAg nanoshells, Nanoscale, 2019,11, 10819-10827.