Story highlights A cluster of infections showed resistance to the single available antibiotic regimen

It's the first time this has happened in the US

(CNN) Seven gonorrhea patients in Hawaii make up the first known US case cluster in which the sexually transmitted infection showed reduced susceptibility to the single available effective treatment option, the Centers for Disease Control and Prevention said today. The patients were diagnosed in April and May.

The six men and one woman were all cured by ceftriaxone and azithromycin, the two-drug regimen recommended for treating gonorrhea by the CDC. However, laboratory tests by the Hawaii State Department of Health showed that the patients' gonorrheal infections did not succumb as easily to the antibiotics as infections have in the past.

"Since 2005, we have seen four isolated cases that showed resistance to both drugs. But the Hawaii cases are the first cluster we have seen with reduced susceptibility to both drugs," said Paul Fulton Jr., a spokesman for the CDC.

This increased resistance serves as an early warning sign, the CDC explained at the 2016 STD Prevention Conference in Atlanta. Someday, these antibiotics may no longer work to cure gonorrhea, which, over the years, has developed resistance to nearly every class of antibiotics used to treat it.

A common STD

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