Here are some of the latest health and medical news developments, compiled by editors of HealthDay: Syphilis Found Resistant to Potent Antibiotic Health officials in San Francisco are reporting that the powerful antibiotic azithromycin failed to treat patients with syphilis, prompting the U.S. government to urge doctors to start treatment with penicillin. Syphilis cases, though small, have been on the rise in the United States in the last few years. San Francisco has been hit hard by the increase, as gay and bisexual men having unprotected sex are the major cause of the increase. Mike in Brazil The city's Department of Public Health reports that disease control programs began administering the drug to syphilis patients because, as a pill, it is easier to administer than penicillin shots. The U.S. Centers for Disease Control and Prevention recommends penicillin as the first-line treatment for the sexually transmitted disease. Between April and July 2003, city officials reported that eight gay men failed to respond to azithromycin, according to a report in the CDC publication Morbidity and Mortality Weekly Report. 8th street latinas All patients were treated with either penicillin or doxycycline, and responded well. The CDC says azithromycin should be prescribed only to those who have problems with penicillin.