Methicillin-resistant Staphylococcus aureus in tertiary care institutions on the Canadian prairies 1990-1992.
OBJECTIVE
To review experience with methicillin-resistant Staphylococcus aureus (MRSA) in tertiary acute-care teaching hospitals on the Canadian prairies.


METHODS
Retrospective review for a 36-month period, 1990 through 1992.


METHODS
Five tertiary acute-care teaching hospitals in three Canadian prairie provinces.


METHODS
MRSA isolates and susceptibility were identified through the clinical microbiology laboratory at each institution. For each patient, data collected included duration of institutional residence prior to isolation, patient ethnic background, age, sex, and antimicrobial susceptibility. Epidemiologic typing of strains used restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis.


RESULTS
Two hundred fifty-nine MRSA isolates were identified in 135 patients during the 36 months, with substantial institutional variation in number of isolates. No consistent increase in yearly numbers of isolates was apparent. Patients usually had MRSA identified at admission (62%); only one of five centers had the majority of isolates acquired nosocomially. Patients with MRSA present at admission were more frequently of aboriginal (First Nations) ethnicity (62% compared with 14% of nosocomial; P < 0.001). Pulsed-field gel electrophoresis of 167 isolates from 135 patients revealed 46 different strains with little interprovincial or interinstitutional identity of strains.


CONCLUSIONS
MRSA isolated in patients in tertiary care institutions in these three Canadian provinces usually is acquired prior to admission. A disproportionate number of isolates are identified in aboriginal Canadians. Epidemiologic typing was consistent with a polyclonal origin of MRSA in this geographic area.
Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
J
J
Embil
K
K
Ramotar
L
L
Romance
M
M
Alfa
J
J
Conly
S
S
Cronk
G
G
Taylor
B
B
Sutherland
T
T
Louie
E
E
Henderson
D000328:Adult; D000416:Alberta / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D005260:Female; D006784:Hospitals, Teaching / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012189:Retrospective Studies; D012525:Saskatchewan / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*