Knoxville (WVLT) - One of the most common sexually transmitted diseases is now a superbug and is resistant to most antibiotics.

The Center for Disease Control and Prevention says gonorrhea has mutated and only a single class of antibiotics called cephalosporins will effectively treat the diseases.

The last time the CDC stopped recommending an antibiotic for gonorrhea was penicillin in the 1980's.

Public health officials say gonorrhea resistance is a trend they've seen coming.

"Unfortunately with bacteria microbes, you do see resistance with drugs, so it will probably happen again, we just have to monitor that and use the class of drugs that are recommended by the CDC," says public health representative Gary Messer.

The CDC changes treatment recommendations when at least five percent of gonorrhea resists a single dose of an antibiotic.