Ear infections causing acute otitis media, a buildup of fluid in the middle ear, are common in young children, and can be painful and upsetting. The infections can be caused by bacteria or viruses, and a protein biomarker could be used to identify the type of infection and track how well it is responding to treatment.
In a study published in The Pediatric Infectious Disease Journal, young children with acute otitis media had blood tests before infection, on diagnosis of acute otitis media, and then again once they had recovered. The tests were looking for S100A12, a protein expressed by white blood cells in response to some types of infection.
In children with otitis media caused by Streptococcus pneumoniae or Haemophilus influenzae, the levels of S100A12 increased. If the ear infection was caused by nontypeable Haemophilus influenzae or by an ear infection, there was no increase in the protein levels.
As ear infections can be caused by viruses as well as bacteria, and therefore antibiotics will have no effect, using this biomarker could help doctors see which ear infections are treatable by antibiotics and avoid antibiotic use when unnecessary, potentially cutting the development of resistance. The biomarker tests could also help physicians to select the best antibiotic for the infection, and then to see how the treatment is working.