Authors: Martha Powell, Future Science Group
A new antibiotic closthioamide (CTA), discovered in 2010, has demonstrated high activity against gonorrhoea strains in vitro, including isolates known to be multidrug resistant.
Following the recent news regarding concerning levels of drug resistance in gonorrhea, the WHO called for increased research and development efforts to investigate new antibiotics. Victoria Miari, lead author from the London School of Hygiene & Tropical Medicine (UK), explained: “Antibiotic resistance, combined with the reduction of drug development, is one of the biggest health issues facing the world today.
“The problem threatens to render many human and animal infections untreatable, including gonorrhoea. With no effective vaccine available, new antibiotics are urgently needed to tackle this infection which, left untreated, can have very serious consequences.”
In this study, published recently Antimicrobial Agents and Chemotherapy, researchers from the London School of Hygiene & Tropical Medicine and Imperial College London (UK), investigated the action of CTA against a range of gonorrhoea isolates.
The team used 149 clinical samples of N. gonorrhoeae from with infections in the throat, urethra, cervix and rectum; in addition, they analyzed eight WHO reference isolates and four commensal Neisseria strains. Using the agar dilution method, the researchers determined the minimum inhibitory concentrations of CTA to be 0.008 – 0.5 mg/L.
Moreover, the team demonstrated that the novel antimicrobial CTA could inhibit the growth of 146 of the 149 of clinical gonococcal strains at very low levels (≤ 0.125 mg/L). CTA was also discovered to be effective against all of the reference samples provided by WHO, which were known to be antibiotic-resistant.
This study demonstrates the anti-gonococcal activity of CTA was high in vitro, including for drug-resistant strains; however, the drug is yet to be assessed in animals or humans. John Heap, the lead author from Imperial College, commented: “The imminent threat of untreatable antibiotic-resistant infectious diseases, including gonorrhoea, is a global problem, for which we urgently need new antibiotics. This new finding might help us take the lead in the arms race against antimicrobial resistance.”
“The next step will be to continue lab research to further assess the drug’s safety and effectiveness. Despite showing tremendous promise, it will be a number of years before, and if, we can use the drug in real life human cases.”
Miari concluded: “The results of our initial laboratory studies show that closthioamide has the potential to combat N. gonorrhoeae. Further research is needed, but its potential to successfully tackle this infection, as well as other bacteria, cannot be underestimated.”