Calls to screen all pregnant women to test their unborn child's sensitivity to a particular antibiotic have arisen after the results of a study show that its use could lead to permanent deafness. John Shanley, chief executive of Sparks, the medical charity which funded the study at the Institute of Child Health (ICH) said: 'This is a major discovery with very important implications'.
Genetic specialist researchers at the ICH tested blood samples from over 9000 children and found that one in 500 carried a genetic mutation making them susceptible to the commonly used aminoglycoside antibiotics. The drugs are given to an estimated 20,000 premature babies each year to treat gram-negative sepsis, an infection causing inflammation throughout the body, blood poisoning, and also to tackle infections in children with cancer and chronic illnesses such as cystic fibrosis. The drugs are known to have negative side effects including damage to hearing and kidney function, and consequently their dosage is closely monitored.
Maria Bitner-Glindzicz, a consultant geneticist at the ICH who led the study, published the findings in the New England Journal of Medicine. Although the precise nature of the risk aminoglycosides carry has been misunderstood, Bitner-Glindzicz said, 'All [the affected children] are permanently deaf. It was known a side effect was hearing loss, but if doctors found a case of hearing loss in a premature baby, they tended to ascribe it to prematurity... Now we have established it is to do with genetic susceptibility. If you have this mutation and get this class of antibiotics, they have this rapid and extreme effect.'
This stark result has prompted the call for screening. 'The discovery explains one cause of deafness and we believe careful consideration should be given to screening all pregnant women to establish whether they are carrying the specific gene mutation', John Shanley of Sparks said. This echoes the thoughts of the lead authors of the study who '..believe that it will be cost effective to genetically screen groups of patients who will almost certainly receive aminoglycoside antibiotics...before administering the antibiotics. This will allow an alternative antibiotic to be given to anyone who has the mutation'. Bitner-Glindzicz did express her concern about clinically urgent cases in light of the time is currently takes to get the genetic results, however Shanley's suggestion to screen pregnant women would alleviate this difficulty.