Rapid genetic test to identify babies at risk of antibiotic-induced hearing loss

The world's first bedside genetic test that could prevent babies from losing their hearing has proven successful according to the NHS.

The 26 minutes genetic test, called the Genedrive MT-RNR1 test, can identify babies who carry a particular genetic variant that could make them permanently deaf when treated with a common emergency antibiotic. Babies admitted to intensive care with a suspected infection are routinely given an antibiotic called gentamicin within 60 minutes, which is used to safely treat approximately 100,000 babies a year. However, one in 500 babies carry the genetic variant that can make it cause permanent hearing loss. Researchers expect that the new genetic test could prevent permanent hearing loss in 180 babies in England every year.

'I am absolutely thrilled with the success of the study, and that this testing is now going to be used in three of our Trust's Neonatal Intensive Care Units – it's actually going to make a real difference so babies are not going to lose their hearing for a preventable reason,' said one of the study's co-authors Professor William Newman, from the University of Manchester, and who led the initial Pharmacogenetics to Avoid Loss of Hearing (PALoH) study. 'The trial demonstrated that you can deploy rapid genetic testing in a clinical setting, and that the tests can be carried out within the 'golden hour' when severely unwell babies should be treated with antibiotics.'

In the current clinical trial, published in JAMA Pediatrics, researchers at two hospitals in Manchester used the Genedrive MT-RNR1 test to screen 424 newborn babies who required antibiotics for the MT-RNR1 genetic variant. Nurses conducted a cheek swab in the babies which was then inserted into a bedside machine for analysis.

The researchers also compared the mean times in giving the proper antibiotic to the babies screened with and without the new genetic test. They found that the mean times were almost the same, taking about 55 minutes. This means that including the new genetic test in clinical practice does not negatively impact the delivery of care.

To the researchers' knowledge, there are no genetic tests that could screen for the genetic variant in question within the critical first hour when antibiotics should be given to babies with severe infections. This is faster than previous genetic tests which normally would have taken several days.

The genetic test has already benefited some families as conveyed by first year nursing student Mary about her baby Khobi: 'Khobi was born with her bowel outside her tummy, which put her at risk of infection – she needed antibiotics quickly but was given this new genetic test which showed she was susceptible to hearing loss from gentamicin... She was given an alternative antibiotic which didn't affect her hearing'.

Over 300 nurses are now being trained to use the machines across hospitals in Manchester, and it is expected the use of the test will become routine for babies who need antibiotic treatment in hospitals within weeks.

However, the new Genedrive MT-RNR1 genetic test should not be confused with gene drive – a way of using genome editing to replace a natural gene with a new gene, that then gets passed on from generation to generation. Such gene drive technology only works on animals with short reproduction cycles, such as mosquitoes.