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May 1992

Outbreak of Invasive Group A Streptococcal Infections in a Nursing Home: Lessons on Prevention and Control

Author Affiliations

From the Epidemiology Branch, Hospital Infections Program (Drs Auerbach and Jarvis) and Respiratory Diseases Branch, Division of Bacterial and Mycotic Diseases (Drs Schwartz and Breiman), Center for Infectious Diseases, Centers for Disease Control, Atlanta, Ga; Halifax Memorial Hospital, Roanoke Rapids, NC (Ms Williams and Dr Fiorilli); and North Carolina Department of Environment, Health and Natural Resources, Raleigh, NC (Dr Adimora). Drs Auerbach and Adimora are now with the US Public Health Service, Federated States of Micronesia and University of North Carolina Medical Center, Chapel Hill, respectively.

Arch Intern Med. 1992;152(5):1017-1022. doi:10.1001/archinte.1992.00400170099019

Objective.—  Nine outbreaks of group A streptococcal (GAS) infections in nursing homes were reported to the Centers for Disease Control (Atlanta, Ga) during the past two winters. We conducted an intensive epidemiologic and laboratory investigation of one of these outbreaks to determine clinical characteristics, risk factors for transmission and infection, and methods of control and prevention.

Methods.—  Cases were detected using cultures and serologic tests. Matched case-control and retrospective cohort studies were performed to determine risk factors for infection.

Results.—  Between December 13, 1989, and January 31, 1990,16 (20%) of 80 residents, and three (7%) of 45 staff, were infected with GAS. Eleven of the residents had invasive disease and four died. Isolates were available from four persons; all were serotype M-1, T-1. There was strong spatial clustering of cases within the nursing home; having a roommate with prior infection was the most important risk factor. Residents with preexisting decubiti had a reduced risk of infection, perhaps because of stricter infection control practices in their care. No evidence was found for common-source transmission of infection. No further cases occurred after improvement of infection control practices and administration of prophylactic antimicrobials to all residents and staff.

Conclusions.—  Invasive GAS disease is increasing nationwide, and is a potentially serious problem in the growing and high-risk setting of nursing homes. These data suggest that, in this outbreak, a virulent GAS strain was introduced, with subsequent person-to-person transmission. Adherence to infection control practices can prevent or control GAS outbreaks. Prophylactic antimicrobials may be an effective adjunct to control severe or ongoing outbreaks.(Arch Intern Med. 1992;152:1017-1022)