title: Outbreak of invasive group A streptococcal infections in a nursing home. Lessons on prevention and control.
abstract: 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.
authors.affiliation: Epidemiology Branch, Centers for Disease Control, Atlanta, GA.
authors.forename: S B
authors.initials: SB
authors.lastname: Auerbach
authors.forename: B
authors.initials: B
authors.lastname: Schwartz
authors.forename: D
authors.initials: D
authors.lastname: Williams
authors.forename: M G
authors.initials: MG
authors.lastname: Fiorilli
authors.forename: A A
authors.initials: AA
authors.lastname: Adimora
authors.forename: R F
authors.initials: RF
authors.lastname: Breiman
authors.forename: W R
authors.initials: WR
authors.lastname: Jarvis
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005260:Female; D006707:Homes for the Aged / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009657:North Carolina / Q000453:epidemiology; D009735:Nursing Homes / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D013297:Streptococcus pyogenes / Q000302:isolation & purification*