The sexually transmitted disease gonorrhea is becomingly increasingly resistant to antibiotics, leaving few treatments available for the nation's second most common STD, according to the Center for Disease Control (CDC).

The resistance has prompted concern about future treatment of the disease and caused health officials to promote the use of a different class of drugs, currently the last line of defense in the treatment of the disease. Penn State's University Health Services has said they are aware of the problem and will follow CDC's suggestions for treatment.

The Center for Disease Control's most recent Morbidity and Mortality Weekly Report shows widespread resistance to fluoroquinolones, the class of antibiotics used to treat gonorrhea since 1993. The resistance is especially common among heterosexuals and men who have sex with men, but is not limited to any particular sexual behavior or ethnic group, according to Dr. John Douglas, director of CDC's Division of Sexually Transmitted Disease Prevention.

Resistance to the drugs has been increasing since 2002, according to the CDC, and in the past five years the proportion of fluoroquinolone-resistant cases has risen from less than 1 percent to 13.3 percent in the first half of 2006.

The number of resistant cases is even higher in some areas. In Philadelphia, for example, the incidence of fluoroquinolone-resistant cases rose from 1 percent in 2004 to almost 27 percent in 2006, according to the CDC.

Health officials expect the resistant strains will continue to spread, said Dr. Hillard Weinstock, of the CDC's Division for Disease Prevention.

There now remains only one drug that effectively treats gonorrhea -- a class of antibiotics known as cephalosporins, which differ from fluoroquinolones in the way they attack bacteria. Specifically, the CDC recommends the use of ceftriaxone, a cephalosporin that is available as a single injection.

Significant resistance to cephalosporins has not yet been observed, and the CDC is working with state and local governments to monitor potential resistance. Such resistance would be cause for alarm.

"Any emerging resistance would be a significant public health concern," Douglas said. "There are currently no new drugs for gonorrhea in the drug development pipeline. We are running out of options to treat this serious disease," he said.

To prepare for emerging resistance to cephalosporins, CDC plans to partner with government and industry to evaluate alternative treatments for gonorrhea, according to a CDC press release.

At Penn State in 2006, University Health Services did 3,500 tests for gonorrhea, but only treated 10 positive cases, said Margaret Spear, director of University Health Services. The number of incidents on college campuses is probably lower than in the general population, she said.

In the past, University Health Services prescribed the traditional fluorquinolone antibiotics. UHS will now follow the CDC's new guidelines for the treatment of gonorrhea, said Beth Collitt, marketing manager for University Health Services.

Gonorrhea infects an estimated 700,000 people nationwide every year, said Diana Olson, director of communications for the Infectious Diseases Society of America. The highest reported rates of infection are among sexually active teenagers, young adults, and African Americans, Olson said. She said gonorrhea is the second most highly reported STD after chlamydia.

Bacteria develop resistance to antibiotics as a result of an incredibly high rate of mutation, Olson said. As the bacteria change form, the drugs are unable to kill them off because they are designed to attack the bacteria's original form. Olson said it is important patients take the entire prescribed dose of antibiotics even if they start to feel better, because otherwise remaining bacteria could develop resistance.

Gonorrhea is spread through sexual contact. If left untreated, it can cause pelvic inflammatory disease (PID) in women and epididymitis, a painful inflammation of the testicles that can lead to infertility in men, Collitt said. Abstinence and safe sex practices, including monogamy and the use of condoms, are the best ways to avoid contracting the disease, according to the Hershey Medical Center's Web site.

Health officials expect that a nationwide transition to the new guidelines will take time.

"If nothing else, we've got get the word out. People have got to read it," Douglas said.