1. Nosocomial Infections Laboratory Branch, Hospital Infections Program, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia 30333
2. Microbiology Section, Laboratory Service, Veterans Administration Center, Wood (Milwaukee), Wisconsin 53193
3. Departments of Pathology and Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
4. Infectious Disease Section, Medical Service, Veterans Administration Center, Wood (Milwaukee), Wisconsin 53193