Researchers from Australia may have found the key to the spread of antimicrobial-resistant gonorrhea in men who have sex with men (MSM).
With cases of gonorrhea reaching an unprecedented high in 2015, scientists fear that a flaw in common perception about how the infection is transmitted could be to blame. According to the Centers of Disease Control and Prevention (CDC), rates of gonorrhea were up 13% year-over-year in 2015 compared to 2014. This is not only problematic because of the rising rate of infection, but also because gonorrhea has been linked to increased drug resistance. The CDC has recommended reducing the prevalence of gonorrhea as a key strategy to combat this drug resistance, but a Melbourne research team warned that certain “behavioral characteristics” of men who have sex with men (MSM) combined with asymptomatic gonorrhea infections could be foiling efforts to control and reduce the infection rate.
Researchers Christopher Fairley, Jane Hocking, Lei Zhang, and Eric Chow, all of whom are affiliated with the Melbourne Sexual Health Centre in Melbourne, Australia, propose that gonorrhea infections in the pharynx (throat) could be playing a substantial role in the spread of the disease among MSM for several reasons. Pharyngeal gonorrheal infections often go undetected because they are frequently asymptomatic, unlike penile infections, which usually create health problems and discomfort in male patients that lead to identification and treatment. Furthermore, pharyngeal infections have been linked to the presence of gonorrhea in the saliva of infected MSM, which means that the disease could be passed not only to the genitalia or anal regions of a sexual partner, but also to the throat, keeping the infection asymptomatic on both sides of the equation and thereby preventing detection and furthering the spread of the disease.
Given that gonorrhea is particularly prevalent in younger MSM who are more likely to have “kissing only” partners and, by extension, may believe themselves to be safe from the risk of infection and less likely to disclose potential infections, and that the rate of pharyngeal gonorrheal infections was nearly five times that of urethral gonorrheal infections in the study population of 3,034 MSM who attended a Seattle clinic, the research team concluded that there must be some additional factor furthering the spread of the disease. “It is difficult to see how, even with frequent changes in sexual partners, the estimated incidence of pharyngeal infection could arise from urethral infection,” they said. “Unfortunately, there are few studies on gonorrhea transmission between the throats of sex partners to support or refute our suggestion,” the team added. The researchers did cite case reports of transmission through kissing from more than 40 years ago, however, and noted that kissing is a “well-recognized transmission route for other Neisseria species,” of which gonorrhea is one.
If the scientists’ proposed model of transmission is correct, several problems arise specifically for MSM and the doctors who treat them when dealing with gonorrheal infections. These results would mean that MSM tend to transfer gonorrhea infections differently than heterosexuals (for whom 95% of all sexual activity is “penile-vaginal” and therefore far more likely to lead to symptomatic infections and treatment) and must be treated and advised differently whether at risk of infection or already diagnosed. “A preventative approach using condoms [alone] will not work,” the team noted, adding that more frequent screenings (every 3 months instead of the presently-recommended annually) for gonorrhea could help control the spread of an asymptomatic infection. The group also suggested that using an antibacterial mouthwash currently in clinical trials could help prevent pharyngeal infections.
Researchers on the team have also been involved in small trials testing the effectiveness of Listerine Cool Mint and Total Care (21.6% alcohol content) in preventing gonorrheal infections. It should be noted that study included only 58 MSM who were culture-positive before using the solution and that using the rinse did not resolve the infection but only reduced culture-positivity on the pharyngeal surface. The data does suggest, however, that the treatment could have important implications for prevention strategies, Chow, Fairley, and the team working on the mouthwash project said. “We are currently conducting a larger clinical trial with a longer follow-up period to validate our preliminary findings,” Chow told Contagion, adding that the larger study will include laboratory works to determine which mouthwash is the most effective.
It is important for providers and patients to realize that at this point, these results are preliminary and, furthermore, that traditional antimicrobial treatments are working in the United States, at least, to deal with gonorrhea infections. CDC spokeswoman Donnica Smalls noted that the highest priority for the Centers at this point in time is to ensure health providers “continue treating gonorrhea with a combination of ceftriaxone and azithromycin right away to fully cure infection and prevent transmission.” She added, “new drugs are urgently needed” although in the United States, there have yet not been any confirmed failures of the CDC-recommended dual treatment. However, CDC researchers did publish research in July 2016 indicating that gonorrhea isolates were showing decreased susceptibility to azithromycin, an early indicator that there could be issues with the treatment in the future. “History shows us that bacteria will find a way to outlast the antibiotics we’re using to treat it,” warned Jonathan Mermim, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and Tuberculosis Prevention.