Drug-resistant gonorrhea hits North America, study says

by Mike Andrew - SGN Staff Writer

An antibiotic-resistant strain of gonorrhea has appeared in North America for the first time, according to a new study published January 8 in the Journal of the American Medical Association.

Canadian scientists led by Vanessa Allen of Public Health Ontario found that 6.7% of gonorrhea patients at their Toronto clinic still tested positive for the disease even after being treated with cefixime, the last remaining oral antibiotic used to treat gonorrhea.

Of 133 patients who returned for a 'test of cure' visit, nine remained gonorrhea-positive. According to the study, this is the first time cefixime-resistant gonorrhea has been found in humans in North America.

'These are the clinical cases we've been waiting for,' Allen told reporters. 'This is the translation of the lab information into what the clinical consequence is.'

A TROUBLING DEVELOPMENT
In an editorial accompanying the report, Dr. Robert D. Kirkcaldy of the Division of STD Prevention, Centers for Disease Control and Prevention, writes that the findings of this study were expected, but 'its arrival is deeply troubling; clinicians now face the emergence of cephalosporin-resistant N gonorrhoeae without any well-studied, effective backup treatment options.

'New antibiotics for treating gonococcal infections are needed,' Kirkcaldy added.

Clinical trials sponsored by the National Institute of Allergy and Infectious Diseases are currently studying new combinations of existing drugs, and a small study of a new oral medication is also under way.

Nevertheless, 'the antibiotic pipeline is running dry,' Kirkcaldy warned, and 'continued investment in antibiotic development is critical.'

INFECTION WIDESPREAD
Gonorrhea is the second-most common sexually transmitted disease in the U.S., with more than 300,000 cases reported in 2011.

The CDC has been monitoring gonorrhea strains around the country for several decades. As part of their study of the disease, they have taken samples of the bacteria from patients and tested how much cefixime is needed to kill them in the lab.

The necessary dose of cefixime has increased slowly over the past ten years, the CDC says. In August CDC officials told doctors to stop using cefixime altogether and switch to a related drug called ceftriaxone, or Rocephin, in order to preserve cefixime's effectiveness.

While the patients in the Canadian study all eventually recovered when they were given larger doses of cefixime or the related ceftriaxone antibiotic, Allen worries that gonorrhea will quickly acquire resistance to ceftriaxone as well, especially since it works by a similar mechanism as cefixime.

'We need to rethink our strategy of antibiotic use,' she said. 'We don't have luxury of just switching to another antibiotic,' she says, 'because there really aren't any more left for gonorrhea.'

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