Is Carbon Monoxide the Key to Fighting Antibiotic-Resistant Gonorrhea?

Troubling incidents of antibiotic-resistant gonorrhea have been popping up around the world, particularly in England and Japan. As a result, new treatments to battle these infections are sorely needed. To this end, in a new study out of the University of York in the United Kingdom, researchers utilized, “the therapeutic effects of carbon monoxide-releasing molecules to develop a new antibiotic which could be used to treat the sexually transmitted infection.”

Gonorrhea is “the second most commonly reported notifiable disease in the United States,” according to the Centers for Disease Control and Prevention (CDC). A common symptom of infection for both men and women is “a burning sensation when urinating;” however, most infected individuals do not show any symptoms. Indeed, these asymptomatic infections (which can occur in the genitals, rectum, and throat) are proposed to be the main driver in the spread of infections; particularly those with antibiotic-resistance. The CDC estimates that up to 30% of new infections each year are resistant to at least one drug, and as of now, healthcare practitioners are down to one class of antibiotics to treat gonorrhea: cephalosporins.

England is dealing with similar issues as gonorrhea is also the second most common sexually transmitted infection there as well. With close to 35,000 cases of the infection reported in England in 2014, and numbers rising every year, researchers have been studying new options against the bacteria.

In their study, researchers from the Biology and Chemistry departments at the University of York, “targeted the ‘engine room’ of the bacteria using carbon monoxide-releasing molecules (CO-RMs),” according to a press release. The rationale behind this research was that evidence suggests that CO, which is naturally produced in the body, “enhances antibiotic action with huge potential for treating bacterial infections.”

The researchers found that Neisseria gonorrhoeae, “is more sensitive to CO-based toxicity than other model bacterial pathogens, and may serve as a viable candidate for antimicrobial therapy using CO-RMs.” The molecule prevents the bacteria from producing energy by binding to them. "The carbon monoxide molecule targets the engine room, stopping the bacteria from respiring. [Neisseria gonorrhoeae] only has one enzyme that needs inhibiting and then it can't respire oxygen and it dies,” said Professor Ian Fairlamb, from the University of York Department of Chemistry, in the press release.

Although CO is toxic at higher concentrations, Professor Fairlamb added that, “Here we are using very low concentrations which we know the bacteria are sensitive to. We are looking at a molecule that can be released in a safe and controlled way to where it is needed."

The research team will next be looking into developing a drug based on these findings.

As part of the ongoing surveillance for antibiotic-resistant gonorrhea infections, the CDC is advising all healthcare practitioners in the United States to, “report any Neisseria gonorrhoeae specimen with decreased cephalosporin susceptibility and any gonorrhea cephalosporin treatment failure to CDC through their state or local public health authority.” In addition, “in the United States, reports of apparent failures of infections to respond to treatment with CDC-recommended therapies should be reported to Robert D. Kirkcaldy, MD, MPH (rkirkcaldy@cdc.gov).