Surveillance at Holland Bloorview
The method of calculation of the MRSA bacteraemia infection rate for the reporting period (on a quarterly basis) is:
Number of nosocomial patients with laboratory identification of MRSA bacteraemia x 1000 Total number of patient days.
Where the numerator is the total number of newly identified cases for MRSA bacteraemia associated with the reporting facility, for the reporting period.
The denominator is the total number of in patient days for the reporting period. There are no exclusion criteria.
For smaller facilities that have only a small inpatient population, like Holland Bloorview, MRSA rates may vary from month to month. In fact, the smaller the facility, the greater the rates will vary, because a change in even one case in a small facility will cause the rate to go up or down considerably.