title: Surveillance for hospital outbreaks of invasive group a streptococcal infections in Ontario, Canada, 1992 to 2000.
abstract: BACKGROUND
  Streptococcus pyogenes can cause severe disease in the individual patient and dramatic hospital outbreaks.
  
  
  OBJECTIVE
  To describe the epidemiology of hospital outbreaks of invasive group A streptococcal infection in order to understand the potential benefit of proposed outbreak investigation and management strategies.
  
  
  METHODS
  Prospective, population-based surveillance.
  
  
  METHODS
  Short-term care hospitals in Ontario, Canada.
  
  
  METHODS
  Persons with a positive culture for group A streptococcus from a normally sterile site between 1 January 1992 and 31 December 2000.
  
  
  METHODS
  Laboratory-based surveillance identified patients with nosocomial invasive group A streptococcal infection. Epidemiologic and microbiological investigations were used to detect transmission.
  
  
  RESULTS
  Of 2351 cases of invasive group A streptococcal disease, 291 (12%) were hospital acquired. Twenty-nine (10%) nosocomial cases occurred as part of 20 outbreaks. Seventy percent (14 of 20) of outbreaks involved nonsurgical, nonobstetric patients. Community-acquired cases initiated 25% of outbreaks; most were cases of necrotizing fasciitis in patients admitted to the intensive care unit. Outbreaks were small (median, 2 cases [range, 2 to 10 cases]) and short (median duration, 6 days [range, 0 to 30 days]). The median time between the first 2 cases was 4.5 days. The most common mode of propagation was patient-to-patient transmission. A staff carrier was the primary mode of transmission in 2 (10%) outbreaks, but 1 or more health care workers were colonized with the outbreak strain in 6 of 18 (33%) other outbreaks.
  
  
  CONCLUSIONS
  Some outbreaks with 1 case of invasive disease may have been missed; advice provided to participating hospitals may have reduced the number and size of outbreaks.
  
  
  CONCLUSIONS
  Practices to prevent hospital transmission of group A streptococci should include isolation of patients admitted to the intensive care unit with necrotizing fasciitis, investigation after a single nosocomial case, and emphasis on identifying and treating health care worker carriers on surgical and obstetric services and patient reservoirs on other wards.
authors: University of Toronto, Mount Sinai Hospital, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors: Nick
authors: N
authors: Daneman
authors: Karen A
authors: KA
authors: Green
authors: Donald E
authors: DE
authors: Low
authors: Andrew E
authors: AE
authors: Simor
authors: Barbara
authors: B
authors: Willey
authors: Benjamin
authors: B
authors: Schwartz
authors: Baldwin
authors: B
authors: Toye
authors: Peter
authors: P
authors: Jessamine
authors: Gregory J
authors: GJ
authors: Tyrrell
authors: Sigmund
authors: S
authors: Krajden
authors: Lee
authors: L
authors: Ramage
authors: David
authors: D
authors: Rose
authors: Ruth
authors: R
authors: Schertzberg
authors: Delena
authors: D
authors: Bragg
authors: Allison
authors: A
authors: McGeer
mesh_terms: D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D004196:Disease Outbreaks / Q000517:prevention & control; D018562:Disease Transmission, Infectious; D019115:Fasciitis, Necrotizing / Q000453:epidemiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D017053:Infection Control; D009864:Ontario / Q000453:epidemiology; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology / Q000517:prevention & control; D011446:Prospective Studies; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D013297:Streptococcus pyogenes