CHICAGO (Reuters) – Health officials are urging doctors to stop using a key antibiotic to treat routine cases of gonorrhea due to signs of bacterial resistance, leaving one treatment left for the sexually transmitted disease.

The U.S. Centers for Disease Control and Prevention said on Thursday it no longer recommends the use of cefixime, marketed under the brand name Suprax by Lupin Ltd, because it is becoming less effective. That leaves the injectable generic antibiotic ceftriaxone, used in combination with another antibiotic, as the last treatment option.

“The change in antibiotic treatment guidelines we are making today is a critical pre-emptive strike to preserve the last effective treatment option,” said Dr. Gail Bolan, director of the CDC’s Sexually Transmitted Disease Prevention division.

“This will not solve the problem of drug-resistant gonorrhea once and for all, but it may buy us time to allow researchers and drug developers to develop new treatments,” Bolan told reporters in a telephone briefing.

Until new treatments reach the market, experts say the best way to reduce the risk of drug-resistant gonorrhea is to rapidly diagnose the disease and fight it with combinations of two or more types of antibiotics at the same time.

This technique is used in the treatment of some other infections like tuberculosis in an attempt to make it more difficult for the bacteria to learn how to overcome the drugs.

SUPERBUG STRAINS

If left untreated, gonorrhea can lead to pelvic inflammatory disease, ectopic pregnancy, stillbirths, severe eye infections in babies and infertility in both men and women.

In the United States, there are approximately 300,000 reported cases of gonorrhea each year, but because infected people often have no symptoms, the actual number of cases is likely closer to 700,000, Bolan said.

So-called “superbug” drug-resistant strains of gonorrhea accounted for almost one in 10 cases of sexually transmitted disease in Europe in 2010, more than double the rate of the year before, health officials from the Stockholm-based European Centre for Disease Prevention and Control said in June.

Dr. Robert Kirkcaldy of the CDC said there have so far been no U.S. cases of “untreatable” gonorrhea, in which the germ resists all known treatments, but U.S. laboratory data suggest resistance is beginning to emerge.

The guidelines also recommend that healthcare providers closely monitor their patients for treatment failure, and retest patients with persistent symptoms with a culture-based gonorrhea test, which can identify antibiotic-resistant infections.

Doctors said cefixime may be needed as an alternative treatment option in some cases. If ceftriaxone is not readily available, providers may prescribe a dual therapy of cefixime plus one of two other antibiotics: azithromycin or doxycycline.

In addition to closely monitoring for resistance nationally, CDC said it is working with the World Health Organization to monitor for emerging resistance on the global level.

The agency is also collaborating with the National Institutes of Health to test new combinations of existing drugs.

(Additional reporting by Kate Kelland in London; Editng by Michele Gershberg)