New antibiotic developed to fight 'superbug' lung infections could be used to treat ventilator-associated pneumonia in COVID-19 patients

• Pneumonia is a serious secondary infection that can arise alongside COVID-19
• 'D8' can combat such deadly lung infections in mice and human cells in the lab
• It might also find application among vulnerable patients with cystic fibrosis
• Found by chance, the drug is less toxic and more effective than its predecessor

A new antibiotic developed to fight 'superbug' lung infections could be used to treat ventilator-associated pneumonia in COVID-19 patients, a study has suggested.

Researchers have shown that the drug can successfully combat potentially fatal lung infections in both mice, as well as human cells grown in the laboratory.

The medication could help to extend the lives of cystic fibrosis sufferers, who are vulnerable to infections that affect their breathing.

It also offers the hope of potentially slashing deaths rates from the coronavirus by stopping secondary infections from colonising a patient's airways.

This is a particular problem for critically ill patients on ventilators — who are especially prone to developing pneumonia.

A new antibiotic developed to fight 'superbug' lung infections could be used to treat ventilator-associated pneumonia in COVID-19 patients, a study has suggested

The powerful drug is a so-called 'engineered cationic antimicrobial peptide', or 'eCAP', that works by 'punching into' bacteria — thereby destroying them.

They are a synthetic and more efficient version of the naturally occurring antimicrobial proteins that form a first line of defence against infections in humans.

The team was working with an eCAP called WLBU2 when they stumbled on a way to both make it less toxic and, at the same time, more effective.

'We were so surprised and happy,' said paper author and epidemiologist Peter Di of the University of Pittsburgh, Pennsylvania.

'At first, we were sceptical and repeated the experiment — but yes, it was 20 times less toxic toward red blood cells in our lab. And when we saw similar results in mice, we were really excited."

The compound is administered via the windpipe to target lung infections — and performs better than current last resort antibiotics, without side effects.

Antimicrobial resistance claims around 700,000 lives a year — a figure set to rise to 10 million by 2050, the World Health Organisation has warned.

It occurs when bacteria rapidly evolve an immunity to drugs — making them harder to combat.

The researchers admitted that the breakthrough came by chance as they looked for ways to make WLBU2 more stable, as so it might stick around longer.

The drug has already been licensed for clinical trials to measure its effectiveness against the infections that can follow knee and hip replacement operations.

When they constructed a near mirror image of WLBU2, dubbed 'D8', they found that it could eliminate the superbug Pseudomonas aeruginosa — which can plague post-surgical patients  — at a fourth of its predecessor's usual concentration. .

In tests, it was found to be much less poisonous than regular WLBU2, killing fewer than 1 per cent of red and 15 per cent of white blood cells.

This was despite the researchers exposing the blood cells to nearly 25 times as much of the antibiotic as would ever be used therapeutically.

'It is one thing to see that in a petri dish, but it is more important to demonstrate the increased safety in a living mammal,' said Professor Di.

In mice, more than 35 micrograms of WLBU2 would likely prove fatal, yet there were no fatalities when D8 was administered at four times that amount — or 100 times the therapeutic quantity.

'This improvement in lowering toxicity, coupled with the new drug's strong stability and activity against superbugs, is good evidence this compound will be well-suited for clinical applications in treating respiratory infections,' said Professor Di.

The team is exploring D8's potential application in cystic fibrosis patients, whose lives can be greatly shortened by drug-resistant lung infections.

They are also are looking at using it to help combat ventilator-associated pneumonia, which has emerged as serious secondary — and potentially more deadly — infection in patients with COVID-19.

The researchers do not yet know why D8 is less toxic, or how well it would be tolerated in the long-term — so more test will be needed before the drug can be used to treat people, Professor Di added. 

The full findings of the study were published in the journal Science Advances.