1. Department of Neurology, Columbia Presbyterian Medical Center, New York, New York.
2. Antibiotic Resistance Unit, Bureau of Communicable Disease, New York City Department of Health and Mental Hygiene, New York, New York.
3. Global AIDS Program, Centers for Disease Control and Prevention, Lusaka, Zambia.
4. Bureau of Communicable Disease, New York City Department of Health and Mental Hygiene, New York, New York.