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Surveillance for invasive group A streptococcal infection

Status: Completed in Ontario / Ongoing in TIBDN hospitals


Population based surveillance for invasive group A streptococcal disease has been ongoing in Ontario (including Metropolitan Toronto/Peel region) since 1992. In 2002, 354 cases of invasive group A streptococcal disease was reported in Ontario, 185 (52%) of which were in the Metro Toronto/Peel region population area. This surveillance program has been responsible for monitoring changes in rates of invasive disease (most notably necrotizing fasciitis and streptococcal toxic shock), assessing the impact of new therapies on outcomes (eg. Use of IVIG for STSS), and defining various spectrums of disease and their risk factors (eg. Streptococcal pneumonia, streptococcal soft tissue infections, and nosocomial group A strep disease). The Toronto Invasive Bacterial Diseases Network will continue to perform population-based surveillance in metropolitan Toronto and Peel Region for disease associated with an isolate of group A strep from a normally sterile site.


The microbiology laboratories serving hospitals in Toronto, Peel, Durham, Simcoe, Hamilton, Halton and York Regions and the three largest private laboratories will continue to report invasive group A streptococcal isolates to the study office and forward the bacterial isolate to the study laboratory. The postal code of residence of the patient will be screened to determine eligibility: Cases will be eligible if the postal code of their home address is within the defined population areas. Homeless persons who visit hospitals in the area are also considered residents. Annual audits of cultures from all laboratories will be performed to evaluate reporting accuracy.

Initial demographic data available from the reporting laboratory is used to determine eligibility of the case. Eligible cases are assigned a unique study ID which is used to identify laboratory samples and data collection forms. A patient chart review will be conducted to determine specific demographic and risk factor data as well as information on treatments and outcomes of infection. All data is recorded on a standardized data collection form previously approved by Research Ethics Boards of all participating hospitals. All data forms and isolates are identified with study code numbers only and cannot be linked to any specific individual. All isolates from surveillance are shipped to the central study lab where they are confirmed as group A strep using standard methodology. Serotyping is performed by the National Centre for the Streptococcus at the National Microbiology Laboratory in Winnipeg, MB.