Onion type may help fight drug-resistant TB

A type of onion may hold the key to fighting antibiotic resistance in cases of tuberculosis, according to a study led by an Indian-origin researcher.

The study led by Sanjib Bhakta of University College London (UCL) in the UK found that the antibacterial properties extracted from the Persian shallot could increase the effects of existing antibiotic treatment. When a patient has a bacterial infection, they may be prescribed an antibiotic.

In the case of TB, they will likely be prescribed a cocktail of four antibiotics including Isoniazid and Rifampicin – but increasingly, the pathogens in bacterial infections are developing resistance to antibiotic drugs.  This means the drug loses its ability to effectively control or kill harmful bacteria, and is free to grow and cause further damage to the patient which, can be passed along to the population at large.

The team investigated extracts of bulbs from Allium Stipitatum – also known as the Persian shallot and used as a staple part of Iranian cooking – and its antibacterial effects.

Researchers synthesised the chemical compounds present in these plants in order to better understand and optimise their antibacterial potential.

They tested four different synthesised compounds, all of which showed a significant reduction in the presence of the bacteria in the multidrug-resistant tuberculosis – the most promising candidate of which, with highest therapeutic index, inhibited growth of the isolated TB cells by more than 99.9 per cent.

The team concluded that the chemical compounds may work as templates for the discovery of new drug treatment to combat strains of tuberculosis, which have previously developed resistance to anti-bacterial drugs.

“Despite a concerted global effort to prevent the spread of tuberculosis, approximately 10 million new cases and two million deaths were reported in 2016,” said Bhakta, who led the study, published in the journal Scientific Reports.  “As many as 50 million people worldwide are currently infected with multi-drug resistant TB, which means it is vital to develop new antibacterials,” he said.  “In this study we show that by inhibiting the key intrinsic resistance properties of the TB, one could increase the effects of existing antibiotic treatment and reverse the tide of already existing drug resistance,” Bhakta added.