Gonorrhea may be growing resistant to the only remaining class of antibiotics left to treat the sexually transmitted disease, U.S. health officials say. Currently, the Centers for Disease Control and Prevention, recommends a dual therapy of cephalosporins, a class of antibiotics often used to treat sexually transmitted disease, with either azithromycin -- antibiotics used often for bacterial infections such as middle ear infections, strep throat, pneumonia, typhoid and sinusitis -- or doxycycline, part of the tetracycline antibiotics group, frequently used to treat chronic prostatitis, sinusitis, syphilis, chlamydia, pelvic inflammatory disease, acne and rosacea. If cephalosporins becomes increasingly resistant to gonorrhea, it would substantially limit treatment options, CDC officials say. Researchers analyzed 10 years\' worth of gonorrhea samples isolates from male patients in 30 U.S. cities collected through CDC\'s Gonococcal Isolate Surveillance Project. The study, published in the CDC\'s Morbidity and Mortality Weekly Report, finds an increase in the proportion of samples with elevated minimum inhibitory concentrations the lowest concentration of antibiotics needed to stop the growth of gonorrhea bacteria suggesting a decline in gonorrhea\'s susceptibility to antibiotics. The revised recommendations are published in the CDC\'s Morbidity and Mortality Weekly Report.