Some commonly used antibiotics can save lives – but they can also damage hearing. RNID‑funded research is working to find ways to prevent or reduce hearing loss caused by a class of antibiotics known as aminoglycosides.
This is Cystic Fibrosis Awareness Week. We’re highlighting how antibiotic‑related hearing loss affects people living with cystic fibrosis, and how RNID and Cystic Fibrosis Trust are working together to tackle this problem.
If you have any concerns about medication you’re taking, speak to your GP, pharmacist or another healthcare professional.
Why antibiotic‑related hearing loss matters
Some medicines have side effects. Certain cancer drugs, such as cisplatin, and some antibiotics can damage the delicate sound‑sensing cells – known as hair cells – in the inner ear. When these cells are damaged, hearing loss can occur, and in severe cases it can be permanent.
Aminoglycosides are a group of antibiotics used worldwide to treat serious bacterial infections. However, they are also known to be ototoxic, meaning they can damage hearing. Around 1 in 5 people treated with aminoglycosides develop hearing loss, with the risk increasing for those who need repeated treatment or who carry genetic variants that make them more vulnerable.
Despite this risk, aminoglycosides are still widely used. They are effective, inexpensive, and have low levels of antibiotic resistance. They are used to protect premature babies from infection and to treat people with cystic fibrosis who develop persistent lung infections. As a result, people with cystic fibrosis are at particularly high risk of antibiotic‑related hearing loss.
What RNID‑funded research has already achieved
Pioneering RNID‑funded work led by Professor Bill Newman at the University of Manchester resulted in a rapid genetic test that identifies newborn babies at high risk of hearing loss from the aminoglycoside antibiotic gentamicin.
For babies who test positive, clinicians can switch to equally effective antibiotics that do not put hearing at risk. This innovation has now been backed by the National Institute for Health and Care excellence, NICE, which has recommended uptake of the Genedrive test by NHS commissioners, helping to protect babies’ hearing across the UK.
However, in many situations – including cystic fibrosis – aminoglycosides cannot be avoided. This is why RNID continues to fund research into protecting the ear itself.
Developing safer antibiotics: joint funding with Cystic Fibrosis Trust
In 2022, we partnered with Cystic Fibrosis Trust to co-fund a Discovery Research Grant led by Professor Alan Cheng at Stanford University, USA. The aim of this project is to develop new or modified aminoglycoside antibiotics that do not damage the sound‑sensing hair cells of the inner ear.
Aminoglycosides cause hearing loss by entering hair cells and irreversibly damaging them. One promising approach is therefore to prevent these drugs from entering the hair cells in the first place – while preserving their ability to fight infection.
Professor Cheng’s team tested modified versions of aminoglycoside antibiotics on hair cells grown in the lab to assess their toxicity. The most promising candidates were then tested in mice to explore whether they could effectively treat infection without causing hearing loss.
Professor Cheng said:
We were able to develop a novel modified aminoglycoside that is significantly less ototoxic, both ‘in vitro’ and ‘in vivo’, while maintaining their antimicrobial efficacy. We aim to expand this class of novel non-ototoxic aminoglycosides and test them clinically in the future. We are tremendously grateful for funding from RNID and Cystic Fibrosis Trust.”
Understanding how antibiotics damage hearing
In 2024, RNID awarded a Discovery Research Grant to Professor Jonathan Gale and Professor Sally Dawson’s laboratories at the University College London Ear Institute. Dr Jack Martin in their team is working to understand whether structures inside cells – called stress granules – play a role in hearing loss caused by aminoglycoside antibiotics.
Stress granules form when cells are under stress, such as exposure to toxins. They help protect the cells and disperse once the stress has passed. However, abnormal stress granules can persist, and these have previously been linked to hearing loss.
The UCL Ear Institute team has two main aims:
- to understand how stress granules behave under chronic cellular stress and how this contributes to age-related hearing loss
- to investigate whether stress granules are involved in hearing loss caused by aminoglycosides and whether targeting them could protect hair cells
The researchers are comparing normal and abnormal stress granules to identify potential drug targets that could prevent damage to hearing. We asked them for an update on their work.
Dr Jack Martin said:
In our RNID funded research we have shown that aminoglycoside antibiotics induce stress granules in cochlear hair cells. While we continue to study their composition, they appear to be similar to ‘typical’ stress granules, but we think that their full ‘protective effect’ is not being utilised.
This provides an opportunity for targeting stress granule induction to protect hair cells. To better understand how stress granules provide protection we are developing a system where we can activate stress granules with a particular wavelength (colour) of light in the absence of any actual cellular stress.”
Professor Jonathan Gale said:
Going forward, we are excited to use this unique experimental tool to better understand the potential role of stress granules in protecting cochlear hair cells from damage, such as that caused by aminoglycoside antibiotics, which are still heavily used, especially by cystic fibrosis patients.”
Our vision: protecting hearing during life‑saving treatment
RNID will continue to fund research to prevent or reduce hearing loss caused by ototoxic medicines, including both cancer treatments and antibiotics.
By supporting research to develop:
- drugs that protect the inner ear from damage, and
- safer, less toxic antibiotics
We aim to ensure that people with serious infections – including those living with cystic fibrosis – can receive life‑saving treatment without losing their hearing.
As part of this work, RNID is again partnering with Cystic Fibrosis Trust on a joint funding call to tackle antibiotic‑related hearing loss. We will share updates on the projects funded through this partnership next year.