Human World

Gonorrhea reaching for superbug status, still

Gonorrhea, a bacterial infection transmitted through sexual contact, met its match during the 20th century thanks to antibiotics like penicillin. But Neisseria gonorrhoeae, the wily and rapidly evolving bacteria that causes gonorrhea, may have outwitted all of our antibacterial defenses, with one strain now emerging as a globally threatening gonorrhea suberbug. Still.

Gonorrhea has been plaguing humans for centuries, a stealth bacterium that often lurks asymptomatically in women but can cause significant symptoms and infertility in men and women. It’s not limited to infecting adults. Babies passing through the birth canal can contract the infection, which can make them blind. Indeed, a paper published in the journal Pediatrics in 1946 reported successful penicillin treatment of gonorrhea, more colloquially known as “the clap,” in 21 one cases in children. According to the article summary, “prompt cure was established in every case.”

That success rate was not fated to last for long. Gonorrhea had already defeated previous antimicrobial efforts against it, using a class of drugs called sulfonamides. Penicillin entered the anti-gonorrheal arsenal by 1943 in a U.S. military hospital. Yet by 1946, penicillin-resistant cases had already begun to emerge, and resistance was being “alleged” by 1948, according to one medical paper.

By 1989, the U.S. Centers for Disease Control and Prevention (CDC) was reporting that in a single year, cases of penicillin-resistant gonorrhea had increased by 131%. Even then, 22 years ago, experts were warning about the need for new antibiotics to tackle the rapidly adapting microbe, which also was showing signs of resistance to another antibiotic, tetracycline.

New antibiotics were adopted against the burning infection, including ciprofloxacin, which not coincidentally became a first-line therapy against gonorrhea in 1989, the year the CDC reported high rates of penicillin-resistant cases. Yet, by 1998, a “drift” to reduced bacterial susceptibility to the drug started building in the UK.

Within a few years, that drift had grown into a full-blown resistance, leading to abandonment of ciprofloxacin and other antibiotics of its class in favor of another group of antibiotics, the cephalosporins, or of azithromycin, a relative of an older antibiotic, erythromycin. Then, researchers began to identify gonorrhea cases from Japan to Norway that resisted cure with any available antibiotics. The burning infection of the mouth and pharynx, penis, vagina, or anus, the blinder of newborns, seemed poised for a return to its era of pre-penicillin voracity, a time when the go-to “cures” for the clap might have included potions of silver or mercury, often injected directly into the urethra. Speaking of urethras, the person whose name is bestowed upon the gonorrheal bacterium, Albert Ludwig Sigesmund Neisser, in testing his newfound microbe, injected it into the urethras of healthy men to see if it did, indeed, cause gonorrhea. It did.

What has driven Neisseria gonorrhoeae’s rapid and continued evasion of the human antibiotic armory? Among other factors, certainly the bacterium shows a phenomenal ability for evolving under antibiotic pressures, leaving only resistant bacteria to carry on. But more is required for the emerging global nature of this resistance; after all, Norway and Japan are quite a long way away from each other. The other factors are the hosts and how we behave. We’ve hit the 7 billion mark globally, so clearly, humans are still having sex. Add to that our ability to take ourselves and whatever bacteria we’re hosting to any part of the globe in a matter of hours—and to continue having sex—and Neisseria gonorrhoeae has all the features in place to achieve infamy as the global superbug of the early 21st century. Researchers have detailed with some precision the global travelers historically most involved in transmission of resistant gonorrheal infection, including “sex tourists” and “long-distance truck drivers.”

While cases resistant to the best antibiotics available have yet to emerge in the United States, the CDC has noted an increase in strains that show decreased susceptibility to cephalosporins. Although the current CDC advice is that these drugs still work against gonorrhea, that “drift” to decreased susceptibility sounds suspiciously like the 1998 drift away from ciprofloxacin.

Interestingly enough, while recent news reports in July 2011 have trumpeted a potential superbug gonorrhea as a new concern for the globe, it’s really somewhat old news. In April 2010, very similar stories and dire warnings emerged from a scientific meeting in Scotland. The stories then were quite like the stories now, warning of a gonorrhea superbug. The threat continues.

What can anyone do to stop this onward march of resistance and spread? One option is a wait-and-see attitude. While a Japanese group has reported identifying a strain that resists “most” antimicrobials tested, the authors also note that no one knows how persistent this strain will prove to be. But, rather than waiting around for a burning sensation from a gonorrheal infection, there may be other ways to avoid the spread of an untreatable gonorrheal superbug. Behavioral modifications (that means you, sex tourists) and public health awareness campaigns are a start. But, as seemingly every article in recent decades on resistant gonorrhea has noted, the great anti-gonorrheal hope remains a constant factor: We need new antibiotics to combat any emerging gonorrheal superbug.

July 23, 2011
Human World

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