New parents know this: when the body temperature of a child who is less than three months old reaches or exceeds 38°C, it is necessary to take a trip to the pediatrician (or, if it is Saturday or Sunday, go to the emergency room) to understand whether the fever is caused by a bacterial infection or a virus. The problem is that the tests that determine it take several hours to give the result and in the meantime, to be safe, the child is given an antibiotic (and the bacteria become increasingly resistant). What if now, to find out, a blood test was enough that gives the result in 15-20 minutes?
Tommaso Bellini, a specialist in emergency paediatrics, spoke about it at the European Congress of Emergency Medicine in Paris, presenting the results of his study conducted on 85 children aged 90 days: of the little feverish children who come to the emergency room, explains Bellini, only 15% actually have a bacterial infection that requires antibiotics. “In very young children with fever, distinguishing a serious bacterial infection from a viral infection that will resolve spontaneously represents one of the main diagnostic difficulties,” he underlines.
Two proteins
To develop a more rapid test, Bellini and colleagues therefore analyzed the blood samples of young patients, looking in particular for two proteins: CD64 and CD169.
We know from previous studies that these proteins spread into certain blood cells when the body responds to infections: CD64 rises when dealing with bacterial infections, while CD169 rises in response to viruses.
By analyzing the levels of both proteins expressed in two types of white blood cells called neutrophils and monocytes, the researchers were able to correctly identify 15 cases of bacterial infection, 44 of viral infection and 26 cases without any type of infection in progress. All with a simple blood test, which returned the results in just 15-20 minutes.
The French precedent
Bellini’s work develops starting from the studies of Fabrice Malergue, the first to have discovered that looking at the levels of the two proteins could help distinguish viral infections from bacterial infections. While the French researcher had conducted his tests on an adult sample, Bellini extended them to children, “an important step forward”, according to Malergue.
The test developed by Malergue has already been used by one of his collaborators in Martinique, during a dengue epidemic: the analysis correctly detected that some people actually had leptospirosis, a potentially lethal bacterial infection if not treated with antibiotics.
Bellini’s next goal is to expand the study sample, involving 300 to 500 newborns in more hospitals.
