Repurposed antibiotic shows promise

In its old form, the antibiotic is very safe for use but it lacks the necessary antibacterial activity against many bacterial pathogens.

May 21, 2015 12:05 am | Updated 12:05 am IST

By tweaking the antibiotic spectinomycin, researchers have successfully boosted its effectiveness against six drug-resistant bacteria that cause common respiratory and sexually transmitted diseases (STDs). The antibiotic spectinomycin was originally developed to treat gonorrhoea.

The tweaked drug, tested in vivo and on mice, produced excellent results. Once clinical testing is completed, the repurposed antibiotic can prove to be a boon to public health. The results are published today (May 21) in the journal Science Translational Medicine .

In its old form, the antibiotic is very safe for use but it lacks the necessary antibacterial activity against many bacterial pathogens. As a result, in the U.S., spectinomycin has not been used to treat gonorrhoea since 2005.

While more and more pathogens are showing greater resistance against drugs, the pipelines for new drugs are far from keeping up with them. Repurposing old drugs against these pathogens is therefore very encouraging.

The lead author David F. Bruhn from the St. Jude’s Children’s Research Hospital, Tennessee and others modelled the spectinomycin’s binding site in the bacterial ribosome and later tweaked the drug’s structure so it could bind to the ribosomes of a variety of bacteria. By substituting a benzyl molecule, they created six compounds that form a new class of antibiotics that they called aminomethyl spectinomycins.

These were found to be effective against common respiratory tract pathogens — Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila , and Moraxella catarrhalis — as well as the sexually transmitted bacteria — Neisseria gonorrhoeae and Chlamydia trachomatis .

The work “moved the antibacterial activity of the series into a therapeutic range for these agents while also improving pharmacokinetic properties,” they write.

The repurposed antibiotic proved more effective as a result of greater accumulation of the active compound within the bacteria. This was achieved by successfully blocking the efflux pump that removes the active compound from a cell.

In addition to better activity, the repurposed antibiotic had increased chemical stability and pharmacokinetics and had increased half-life. As a request, a lower dose of the tweaked antibiotic was found to be effective in clearing gonorrhoea.

In the case of S. pneumoniae , a predominant cause of childhood upper respiratory tract infection, the tweaked antibiotic proved to be highly efficacious and capable of clearing the pathogens even when lower doses were used.

0 / 0
Sign in to unlock member-only benefits!
  • Access 10 free stories every month
  • Save stories to read later
  • Access to comment on every story
  • Sign-up/manage your newsletter subscriptions with a single click
  • Get notified by email for early access to discounts & offers on our products
Sign in

Comments

Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.

We have migrated to a new commenting platform. If you are already a registered user of The Hindu and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.