Changing epidemiology of methicillin-resistantStaphylococcus aureusin Alberta, Canada: population-based surveillance, 2005–2008

Abstract

SUMMARYIncreasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been reported in Canada. We report the results of a prospective surveillance of MRSA infections in Alberta over a consecutive 3-year period. A total of 8910 unique clinical MRSA isolates was analysed from July 2005 to June 2008. The incidence of MRSA infection increased over the study period and was highest in males, age group ⩾85 years, and the Calgary Area. CMRSA10 (USA300) and CMRSA2 (USA100/800) were the most common PFGE strain types, representing 53·0% and 27·9% of all isolates, respectively. Significant differences were noted between MRSA strains in the source of infection and antimicrobial susceptibility. The incidence of MRSA infection in Alberta has nearly doubled in the last 3 years; this is attributed to the emergence of CMRSA10 as the predominant strain.

A population-based study of the epidemiology and clinical features of methicillin-resistant Staphylococcus aureus infection in Pennsylvania, 2001–2010

“…Consistent with prior studies, the majority of our CA-MRSA cases [9, 11, 16, 20, 26, 35] and many HA-MRSA cases presented with SSTIs, but HA-MRSA also presented with pneumonia, bacteremia, endocarditis, and SSTIs, especially chronic skin ulcers and wound infections [6, 16, 25, 29, 35]. We also identified evidence of prior SSTI as a risk factor for subsequent MRSA infection, even controlling for antibiotic use.…”

Emergence of New CMRSA7/USA400 Methicillin-Resistant Staphylococcus aureus spa Types in Alberta, Canada, from 2005 to 2012

“…Although most Alberta Health Zones saw an increase in CMRSA7/USA400 infection rates from 2010 to 2012, the rate in the North Health Zone increased most dramatically. This was largely due to a nearly 3-fold increase in t1787 infection rates in the North Health Zone and is contrary to previous reports that CMRSA7/USA400 MRSA is found mostly in southern Alberta (15). In contrast, the overall infection rate of t128 MRSA has remained constant from 2010 to 2012.…”

“…Another key difference between t1787 and t128 MRSA is that t1787 isolates were significantly more resistant to mupirocin than t128 isolates. The level of mupirocin resistance for t1787 MRSA is much higher than that previously reported for CMRSA7/USA400 (15,39). One limitation of this study is that a low number of isolates were tested for antimicrobial susceptibility.…”

“…CA-MRSA strains have caused outbreaks among health care workers (6), prison inmates (7,8), military personnel (7), athletes (9,10), tattoo recipients (11), and children (12). In Canada and the United States, the spread of CA-MRSA is mainly attributed to a single dominant epidemic clone, Canadian MRSA 10 (CMRSA10)/USA300 (13,14), which replaced the previous predominant CA-MRSA epidemic clone: Canadian MRSA 7 (CMRSA7)/USA400 (15,16). Despite this, the CMRSA7/USA400 epidemic clone was still common from 2005 to 2008 in the Canadian province of Alberta (15) and has been reported to be the predominate epidemic clone in other Canadian provinces such as Saskatchewan (17) and Manitoba (18), in Nunavut (19), and also in southwestern Alaska, United States (20).…”

Community-based educational intervention to limit the dissemination of community-associated methicillin-resistant Staphylococcus aureusin Northern Saskatchewan, Canada

“…However, since that time two main CA-MRSA strains have emerged in Canada, CMRSA7 (similar to USA400; ST1-MRSA-IV) and CMRSA10 (similar to USA300; ST8-MRSA-IV) [2,6,9,10]. CMRSA10 has been identified predominantly in the western provinces of Canada and high incidences have been reported in the homeless, incarcerated, and intravenous drug user populations in the Calgary [11,12] and Vancouver [13] health regions. CMRSA7 was first reported in Manitoba causing an outbreak in the southern portion of that province in the late 1990's, but spread to northern regions of the province [14-16] and communities further north in Nunavut [17].…”