MMeetthhiicciilllliinn--RReessiissttaanntt SSttaapphhyyllooccooccccuuss aauurreeuuss ((MMRRSSAA)) SSuurrvveeiillllaannccee RReeppoorrtt

Quarter 1, FY 2010/11 – Quarter 2, FY 2011/12

Prepared by: Provincial Infection Control Network of (PICNet) April 2012

Provincial Infection Control Network of BC (PICNet) 555 West 12th Avenue, Suite 400 East Tower, Room 413/414 Vancouver, BC V5Z 3X7 www.picnet.ca Tel: 604-707-2667 Fax: 604-707-2649 Email: [email protected]

MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Table of Contents

Summary ...... 1 Introduction ...... 2 Surveillance results ...... 3 Population under surveillance ...... 3 Overview of MRSA cases ...... 4 Provincial rate of MRSA associated with reporting facility ...... 5 Rate of HCA MRSA by Health Authority ...... 6 Rate of HCA MRSA by size ...... 6 Rate of HCA MRSA by facility ...... 7

Discussion ...... 10 About this report ...... 12 MRSA surveillance system ...... 12 Population under surveillance ...... 12 Data sources ...... 12 Limitations ...... 12

Glossary ...... 14 Surveillance Steering Committee ...... 18

Provincial Infection Control Network of British Columbia (PICNet) i MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Glossary of Acronyms

BC British Columbia CA Community-associated CI Confidence Interval CNISP Canadian Nosocomial Infection Surveillance Program FHA Fraser Health Authority FQ Fiscal quarter FY Fiscal year HA Health Authority HAI Healthcare associated infection HCA Healthcare-associated IHA Interior Health Authority IPC Infection prevention and control MRSA Methicillin-Resistant Staphylococcus aureus NHA Northern Health Authority PHC Providence Health Care PHSA Provincial Health Services Authority PICNet Provincial Infection Control Network of British Columbia SSC PICNet’s Surveillance Steering Committee VCHA Vancouver Coastal Health Authority VIHA Vancouver Island Health Authority

Provincial Infection Control Network of British Columbia (PICNet) ii MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Summary

This is the first provincial surveillance report presenting newly identified cases of Methicillin-resistant Staphylococcus aureus (MRSA) in BC acute care facilities from quarter 1 (Q1) of fiscal year (FY) 2010/2011 to quarter 2 (Q2) of FY 2011/2012 (from April 1, 2010 to September 15, 2011).

A total of 3,548 newly identified cases of MRSA (either infections or colonizations) were reported among inpatients admitted to acute care facilities during this period, of which 1,709 were healthcare-associated (HCA) with the reporting facility (48.2%), 632 HCA with another facility (17.8%), 875 community- associated (CA) (24.7%), and 332 cases of unknown association (9.4%). The provincial incidence rate of MRSA associated with the reporting facility per 10,000 inpatient days was 4.3 [95% CI: 4.1-4.5] for the surveillance period, which was lower than the national average rate of 5.92 per 10,000 inpatient daysa. The provincial rate by quarter was relatively stable until Q2 of FY 2011/2012 when the rate decreased significantly, which requires ongoing monitoring for further validity. The rate of MRSA varied by Health Authority (HA). with more than 250 beds had significantly higher MRSA rates compared to those hospitals with 51-250 beds, whereas the rates in small facilities varied substantially from reporting period to reporting period due to the small numbers of MRSA cases and/or inpatient days. This report aims to increase the understanding of the patterns and trends of MRSA incidence in BC. The rates presented in this report are not adjusted by known risk factors or variations in screening practice, and therefore are not directly comparable between Health Authorities or between facilities.

a For the hospital setting in 2010 (the most recently available national data; refer to Footnote i)

Provincial Infection Control Network of British Columbia (PICNet) 1 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Introduction Staphylococcus aureus (S aureus) is a type of bacterium that frequently lives on the skin and in the nose without causing health problems. S aureus becomes a problem when it is a source of infection in the skin, lungs, or blood. These bacteria can be spread from one person to another through casual contact or through sharing contaminated objects. The emergence of strains resistant to methicillin and other antimicrobial agents, particularly the spread of Methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings, has become a major concern because MRSA infections are more difficult to treat than ordinary S aureus infections, and can cause higher mortalityb,c. In healthcare facilities, surveillance is an important tool and generally accepted method to assess the incidence of healthcare-associated infections (HAI) and, if necessary, to improve infection control measuresd. MRSA in BC hospitals is monitored by each Health Authority (HA). In 2011, the Provincial Infection Control Network of BC (PICNet), in collaboration with representatives from Interior Health Authority (IHA), Fraser Health Authority (FHA), Vancouver Coastal Health Authority (VCHA), Providence Health Care (PHC), Vancouver Island Health Authority (VIHA), Northern Health Authority (NHA), and Provincial Health Services Authority (PHSA), launched provincial surveillance for MRSA in BC’s acute care facilities. A standard case definition for MRSA and a minimum dataset were developed by PICNet’s Surveillance Steering Committee (SSC). The MRSA cases were divided into four groups according to patients’ previous healthcare encounter history: Healthcare-associated (HCA) with the reporting facility, HCA with another facility, Community-associated (CA), and Unknown (See Glossary for definitions). The aggregated data by facility and fiscal quarter were submitted to PICNet by each HA. This report summarizes the MRSA cases identified and rates of MRSA from Quarter 1 (Q1) of fiscal year (FY) 2010/11 to Quarter 2 (Q2) of FY 2011/12 (April 1, 2010 – September 15, 2011). Please note that the MRSA cases in this report represent inpatients that were admitted to acute care facilities and newly identified with MRSA either as infection or as colonization. The rate of HCA MRSA in this report was not adjusted; therefore, comparison of the rates between HAs or between healthcare facilities is not recommended. Many factors can affect the rate of HCA MRSA, such as the intensity of MRSA screening performed by the facility, patients’ exposure history to healthcare and antibiotics, environmental conditions, and prevalence of MRSA in the community.

b Seller JL, et al (2011). The Journal of the American Medical Association c Cosgrove SE, et al (2003). Clinical Infectious Diseases 36 :53-59 d Chaberny IF, et al (2007). Infection Control and Hospital Epidemiology 28:446-452

Provincial Infection Control Network of British Columbia (PICNet) 2 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Surveillance results

Population under surveillance All patients who were admitted to BC acute care facilities for acute care were under surveillance for MRSA. Table 1 summarizes the population under MRSA surveillance for the period from Q1 of FY 2010/2011 to Q2 of FY 2011/2012. Table 1. Summary of population under surveillance by Health Authority, quarter 1 of fiscal year 2010/2011 to quarter 2 of fiscal year 2011/2012 Health Number of Average Total Total Estimated Authority and acute care acute care acute care acute care population hospital size facilities1 beds2 inpatient days admissions in 20113 IHA4 22 4a 1,208 4a 714,378 100,841 741,619 4b 1-50 beds 16 238 194,373 17,996 51-250 beds 5 629 324,100 52,154 >250 beds 1 341 195,905 30,691 FHA 14 2,344 1,420,827 185,868 1,635,340 1-50 beds 4 107 64,094 7,578 51-250 beds 6 777 481,219 60,429 >250 beds 4 1,460 875,514 117,861 VCHA5 9 1,232 638,914 96,363 1,151,320 5a 1-50 beds 6 160 63,797 13,413 51-250 beds 2 428 236,547 41,466 >250 beds 1 644 338,570 41,484 PHC6 2 535 268,445 24,906 51-250 beds 1 101 54,011 4,901 >250 beds 1 434 214,434 20,005 VIHA 12 1,424 740,259 96,342 765,849 1-50 beds 5 84 35,813 4,062 51-250 beds 4 276 145,516 20,811 >250 beds 3 1,064 558,930 71,469 NHA7 18 552 81,391 13,545 289,974 1-50 beds 17 349 46,982 8,721 51-250 beds 1 203 34,409 4,824 PHSA 2 249 138,935 32,939 N/A 51-250 beds 2 249 138,935 32,939 Total 79 7,545 4,003,149 550,804 4,584,102 Note: 1. Number of beds varied by quarter due to temporary closure of acute care beds by facilities. The hospital size was based on the acute care beds in Q2 of FY 2011/2012. 2. Based on the quarterly counts of acute care beds 3. BC Stats. Population projections (P.E.O.P.L.E. 36). http://www.bcstats.gov.bc.ca/ 4. Excluded from this report are four facilities for Q3 and Q4 of FY 2010/2011 and nine facilities for Q1 and Q2 of FY 2011/2012 in IHA that did not have data available due to information system upgrades in progress. 4a. Includes the facilities that were excluded for certain periods from this report 4b. Includes all estimated population within IHA 5. Does not includes PHC, which was listed separately in this report; the same hereinafter. 5a. Includes all estimated population within VCHA 6. PHC is listed separately from VCHA due to the difference in the case definition; see “Limitations” in “About this report” 7. Q1 and Q2 of FY 2011/2012 only. NHA standardized MRSA surveillance with PICNet’s MRSA surveillance protocol from Q1 of FY 2011/2012 in their acute care facilities; the same hereinafter.

Provincial Infection Control Network of British Columbia (PICNet) 3 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Overview of MRSA cases A total of 3,548 new cases of MRSA were identified from Q1 of FY 2010/2011 to Q2 of FY 2011/2012, of which 1,709 were defined as HCA with the reporting facility (48.2%), 632 were HCA with another facility (17.8%), 875 were CA (24.7%), and 332 were of unknown association (9.4%). Figure 1 shows the proportion of each type of MRSA reported by HA. Figure 1. Proportion of newly identified MRSA cases by association and Health Authority, quarter 1 of fiscal year 2010/2011 to quarter 2 of fiscal year 2011/2012

100%

80%

60%

Percentage 40%

20%

0% IHA FHA VCHA PHC VIHA NHA PHSA Healthcare-associated 53.6% 55.4% 42.8% 37.2% 46.4% 46.3% 30.3% with reporting facility Healthcare-associated 1 20.2% 34.5% 2.4% 3 13.4% 46.3% 2 with another facility N/A N/A Community-associated/ 46.4% 24.4% 22.7% 60.4%3 40.2% 7.5% 69.7% Unknown

Total number of cases 504 1208 820 414 433 80 89

Note: 1. IHA classified the MRSA cases other than those associated with the reporting facility as “Community-associated”. 2. PHSA classified cases other than those associated with the reporting facility as “Unknown”. 3. PHC classified MRSA associated with another facility that were within PHC only, and other than those associated with facilities of PHC as “Not PHC-associated”, which was grouped into the category of “Community-associated/Unknown” in this report.

Provincial Infection Control Network of British Columbia (PICNet) 4 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Provincial rate of MRSA associated with reporting facility The provincial average rate of MRSA associated with the reporting facility per 10,000 inpatient days was 4.3 [95% CI: 4.1-4.5] during Q1 of FY 2010/2011 to Q2 of FY 2011/2012. There was no statistically significant difference in the quarterly rates between Q1 of FY 2010/2011 and Q1 of FY 2011/2012 (Figure 2). The rate for Q2 of FY 2011/2012 was significantly lower than the average rate of FY 2010/1011 and Q1 of FY 2011/2012. Figure 2. Provincial rate of MRSA associated with reporting facility by fiscal year and quarter* 8.0

6.0

4.0 Rate per 10,000 inpatient days inpatient 10,000 per Rate 2.0

0.0 Q1 Q2 Q3 Q4 Q1 Q2 2010/2011 2011/2012 Provincial rate of MRSA associated with 4.6 4.7 4.3 4.1 4.5 3.4 reporting facility

Fiscal year and quarter*

Note: Bars in the line chart represent 95% confidence interval of the rates * Data were aggregated by fiscal quarter for each HA except PHSA, which aggregated the data by calendar quarter (for start and end date of each quarter, see Fiscal Year in the Glossary). The same hereinafter.

Provincial Infection Control Network of British Columbia (PICNet) 5 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Rate of HCA MRSA by Health Authority The rate of MRSA associated with the reporting facility varied by quarter and HA (Table 2). Compared with FY 2010/2011, the combined rate for Q1 and Q2 of FY 2011/2012 was significantly lower for VCHA. The difference for other HAs was not statistically significant.

Table 2. Rate of MRSA associated with reporting facility per 10,000 inpatient days by Health Authority

FY 2010/2011 FY 2011/2012 Health Annual Rate Q1 & Q2 Combined Authority Q1 Q2 Q3 Q4 Q1 Q2 (95% CI) (95% CI) IHA 4.7 5.5 3.4 2.6 4.0 (3.5-4.6) 3.3 2.7 3.0 (2.3-4.0) FHA 4.9 4.8 4.8 4.6 4.8 (4.3-5.2) 5.3 3.9 4.6 (4.0-5.3) VCHA 6.4 6.8 7.3 5.0 6.3 (5.6-7.1) 4.0 3.6 3.8 (3.0-4.8) PHC 5.1 3.2 4.9 8.1 5.6 (4.6-6.8) 7.1 5.0 6.0 (4.6-7.9) VIHA 2.8 2.9 1.8 2.8 2.6 (2.2-3.1) 2.9 3.0 3.0 (2.4-3.8) PHSA 1.3 1.7 3.1 0.9 1.7 (1.1-2.8) 2.6 2.2 2.4 (1.3-4.3) NHA 6.7 2.3 4.5 (3.3-6.3) Provincial 4.6 4.7 4.3 4.1 4.4 (4.2-4.7) 4.5 3.4 4.0 (3.6-4.3) Average

Rate of HCA MRSA by hospital size

The rate of MRSA associated with the reporting facility was significantly higher for the hospitals with more than 250 beds than those with 51-250 beds in both fiscal years, and the rate in hospitals with 1-50 beds varied from period to period (Table 3). There was no significant difference between the annual rate of FY 2010/2011 and the combined rate of Q1 and Q2 of FY 2011/2012 for each hospital size category.

Table 3. Rate of MRSA associated with reporting facility per 10,000 inpatient days, by hospital size

FY 2010/2011 FY 2011/2012 Hospital Annual Rate Q1 & Q2 Combined size (beds) Q1 Q2 Q3 Q4 Q1 Q2 (95% CI) (95% CI) 1-50 2.9 4.3 2.5 2.7 3.1 (2.5-3.8) 5.3 2.4 3.9 (2.9-5.2) 51-250 4.8 3.5 4.2 3.1 3.9 (3.5-4.3) 3.6 3.0 3.3 (2.9-3.9) >250 4.8 5.6 4.7 5.0 5.0 (4.7-5.4) 5.0 3.9 4.4 (3.9-4.9) All 4.6 4.7 4.3 4.1 4.4 (4.2-4.7) 4.5 3.4 4.0 (3.6-4.3) hospitals

Provincial Infection Control Network of British Columbia (PICNet) 6 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Rate of HCA MRSA by facility Table 4 below presents the rates of MRSA associated with the reporting facility, listed in alphabetical order of acute care facility. The rate for each facility should be interpreted with caution. The wide range of 95% CI for some facilities is due to the small numerators (i.e., number of HCA MRSA) and/or denominators (inpatient days) leading to a large standard errore, which was used as a base for calculating the CI. The rates in facilities with a wide CI may vary substantially from reporting period to reporting period, as slight changes in case numbers – even one case – can considerably affect the rate. The facilities which had a rate less than two standard errors are denoted in the table below with the letter ‘E’, indicating that the rate may not be reliable.

Example In a facility with 20 acute care beds, if there was one case of MRSA associated with the facility and 5,000 inpatient days in the FY 2010/2011, and one case of MRSA associated with the facility and 2500 inpatient days in Q1 and Q2 of FY 2011/2012, the rates would be 2.0 and 4.0, respectively. As demonstrated in this example, the rate has doubled, although the number of cases has remained the same. For this reason, those rates with small numerators and/or denominators are flagged with the letter ‘E’ in the table below.

Due to the different surveillance strategies and intensity of MRSA screening performed, the rates in this table represent HCA MRSA identified among inpatients in each acute care facility, and are not in any way a measure of the “performance” of the facility. They should therefore not be used to make comparisons between individual facilities. Please see “Discussion” section, and “Limitations” in the “About this report” section.

Table 4. Rate of MRSA associated with reporting facility by facility

Rate for MRSA associated with reporting facility Hospital size per 10,000 inpatient days (95%CI) Acute care facility1 (beds)2 Annual rate, Q1 and Q2 Combined, FY 2010/2011 FY 2011/2012 100 Mile District Hospital 1-50 13.9 (7.3-26.4) 3.3 (0.6-18.9)E Abbotsford Regional Hospital >250 2.8 (2.0-4.0) 2.2 (1.2-4.0) Arrow Lakes Hospital 1-50 0.0 BC Children's Hospital 51-250 2.9 (1.6-5.4) 1.9 (0.6-5.5)E BC Women's Hospital 51-250 1.0 (0.5-2.2) 2.6 (1.3-5.2) Bella Coola General Hospital 1-50 0.0 0.0 Boundary Hospital 1-50 15.6 (5.3-45.9)E Bulkley Valley District Hospital 1-50 10.8 (3.7-31.8)E Burnaby Hospital >250 6.5 (5.2-8.2) 5.5 (3.9-7.9) Campbell River & District General 51-250 4.4 (2.5-7.7) 2.6 (0.9-7.7)E Hospital Cariboo Memorial Hospital and 1-50 2.0 (0.6-7.4)E 0.0 Health Centre Chetwynd General Hospital 1-50 0.0

e For a definition of confidence interval and standard error, please refer to the Glossary.

Provincial Infection Control Network of British Columbia (PICNet) 7 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Rate for MRSA associated with reporting facility Hospital size per 10,000 inpatient days (95%CI) Acute care facility1 (beds)2 Annual rate, Q1 and Q2 Combined, FY 2010/2011 FY 2011/2012 Chilliwack General Hospital 51-250 2.8 (1.7-4.5) 4.7 (2.7-8.2) Cormorant Island Community 1-50 40.9 (13.9-119.6)E 25.6 (4.5-143.4)E Health Centre Cowichan District Hospital 51-250 3.3 (2.0-5.6) 4.1 (2.1-8.2) Creston Valley Hospital 1-50 5.0 (1.7-14.7)E Dawson Creek Hospital 1-50 0.0 Delta Hospital 1-50 1.3 (0.4-3.8)E 5.1 (2.2-11.9) Dr. Helmcken Memorial Hospital & 1-50 0.0 15.9 (2.8-89.5)E Health Centre Eagle Ridge Hospital 51-250 3.4 (2.1-5.8) 1.6 (0.5-4.7)E East Kootenay Regional Hospital 51-250 12.7 (9.1-17.9) Elk Valley Hospital 1-50 9.9 (4.2-23.2) Fort Nelson General Hospital 1-50 24.1 (9.4-61.9) Fort St. John General Hospital 1-50 9.2 (4.2-20.0) Fraser Canyon Hospital 1-50 0.0 0.0 G.R. Baker Memorial Hospital 1-50 1.7 (0.3-9.8)E Golden & District General Hospital 1-50 8.7 (2.4-31.8)E Invermere & District Hospital 1-50 14.6 (5.7-37.5) Kelowna General Hospital >250 4.5 (3.5-5.7) 2.8 (1.7-4.4) Kitimat General Hospital 1-50 3.0 (0.5-17.1)E Kootenay Boundary Regional 51-250 9.0 (4.9-16.6) Hospital Kootenay Lake Hospital 1-50 1.7 (0.3-9.8)E Lady Minto Gulf Islands Hospital 1-50 3.3 (0.9-11.9)E 6.7 (1.8-24.5)E Lakes District Hospital 1-50 0.0 Langley Memorial Hospital 51-250 3.4 (2.3-5.0) 2.7 (1.4-5.1) Lillooet Hospital and Health Centre 1-50 0.0 0.0 Lion's Gate Hospital 51-250 5.9 (4.5-7.7) 5.4 (3.6-8.2) Mackenzie and District Hospital 1-50 51.2 (14.0-184.6)E Masset Hospital 1-50 0.0 Matsqui Sumas Abbotsford 1-50 0.0 4.7 (1.3-17.0)E McBride and District Hospital 1-50 0.0 Mills Memorial Hospital 1-50 4.2 (1.4-12.4)E Mission Memorial Hospital 1-50 7.2 (3.3-15.8) 2.4 (0.4-13.6)E Mount Saint Joseph Hospital 51-250 3.3 (1.9-5.7) 4.7 (2.4-9.2) Nanaimo Regional General Hospital >250 3.0 (2.1-4.3) 4.4 (2.9-6.7) Nicola Valley Health Centre 1-50 10.3 (3.5-30.2)E 6.8 (1.2-38.3)E Peace Arch Hospital 51-250 4.0 (2.8-5.8) 2.7 (1.4-5.1) Penticton Regional Hospital 51-250 2.2 (1.3-3.9) 4.0 (2.2-7.3) Port Hardy Hospital 1-50 0.0 0.0

Provincial Infection Control Network of British Columbia (PICNet) 8 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Rate for MRSA associated with reporting facility Hospital size per 10,000 inpatient days (95%CI) Acute care facility1 (beds)2 Annual rate, Q1 and Q2 Combined, FY 2010/2011 FY 2011/2012 Port McNeill and District Hospital 1-50 0.0 0.0 Powell River General Hospital 1-50 10.7 (6.0-19.2) 6.4 (2.2-18.7)E Prince Rupert Regional Hospital 1-50 2.6 (0.5-14.4)E Princeton General Hospital 1-50 11.7 (3.2-42.6)E 13.3 (2.3-74.9)E Queen Charlotte Islands Hospital 1-50 0.0 Queen Victoria Hospital and Health 1-50 0.2 (0.0-1.1)E 0.0 Centre Queen’s Park Care Centre 51-250 1.8 (0.7-4.6) 1.8 (0.6-5.3)E Richmond Hospital 51-250 3.5 (2.3-5.2) 2.5 (1.3-4.9) Ridge Meadows Hospital 51-250 5.1 (3.6-7.3) 4.2 (2.3-7.5) Royal Columbian Hospital >250 4.4 (3.5-5.6) 5.3 (4.0-7.2) Royal Inland Hospital 51-250 4.5 (3.3-6.2) 4.3 (2.7-6.9) Royal Jubilee Hospital >250 2.3 (1.6-3.1) 3.3 (2.2-4.9) RW Large Hospital 1-50 0.0 0.0 Saanich Peninsula Hospital 51-250 2.2 (1.0-5.2) 1.0 (0.2-5.5)E Shuswap Lake General Hospital 1-50 1.5 (0.8-2.8) 1.3 (0.2-7.6)E South Okanagan General Hospital 1-50 6.1 (2.4-15.8) 3.1 (0.6-17.7)E Squamish General Hospital 1-50 2.0 (0.4-11.2)E 3.9 (0.7-22.3)E St. John Hospital 1-50 0.0 St. Mary's Hospital 1-50 5.9 (3.1-11.3) 0.0 St. Paul's Hospital >250 6.2 (5.0-7.6) 6.4 (4.7-8.6) Stuart Lake Hospital 1-50 13.8 (2.4-77.8)E Surrey Memorial Hospital >250 7.4 (6.3-8.7) 7.2 (5.7-9.0) Tofino General Hospital 1-50 0.0 37.5 (10.3-135.8)E UBC Hospital 1-50 1.0 (0.2-5.4)E 0.0 University Hospital of Northern BC3 51-250 4.4 (2.6-7.2) Vancouver General Hospital >250 7.5 (6.5-8.7) 3.9 (2.9-5.2) Vernon Jubilee Hospital 51-250 2.5 (1.5-4.2) 1.2 (0.4-3.5)E Victoria General Hospital >250 1.9 (1.3-2.8) 0.9 (0.4-2.2) West Coast General Hospital 51-250 3.0 (1.4-6.6) 2.4 (0.7-8.7)E Wrinch Memorial Hospital 1-50 0.0

Notes: 1. A standard surveillance case definition was not in place for the facilities in NHA prior to April 1, 2011. The data were not available for Arrow Lakes Hospital, Boundary Hospital, Kootenay Boundary Regional Hospital, and Kootenay Lake Hospital from Q3 of FY 2010/2011 to Q2 of FY 2011/2012, and Creston Valley Hospital, East Kootenay Regional Hospital, Elk Valley Hospital, Golden & District General Hospital, and Invermere & District Hospital for Q1 and Q2 of FY 2011/2012 due to information system upgrades. 2. Based on the average of quarterly bed counts from Q1 of FY 2010/2011 to Q2 of FY 2011/2012 3. Formerly known as Prince George Regional Hospital E. The rate may not be reliable due to small number of MRSA cases and/or inpatient days.

Provincial Infection Control Network of British Columbia (PICNet) 9 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Discussion This is the first provincial surveillance report presenting newly identified MRSA cases among patients admitted to 79 acute care facilities in BCf. Overall, 66% of newly identified MRSA cases were HCA (including HCA with another facility). The provincial rates of MRSA associated with the reporting facility were 4.3 per 10,000 inpatient days during the period of Q1 of FY 2010/2011 to Q2 of FY 2011/2012. The quarterly rates were relatively stable until Q2 of FY 2011/2012, when the rate decreased significantly. This decrease requires ongoing monitoring for further validity. In , both CA and HCA MRSA have created major medical problemsg. The overall incidence of MRSA has continually increased in the hospital setting in the past decade, and HCA MRSA accounted for nearly two-third of all casesh. In 2010, the national average rate of nosocomial infection (i.e. originating from reporting acute care facilities) increased to 5.92 per 10,000 patient daysi. The proportion of HCA MRSA within all MRSA cases in BC acute care facilities was similar to the national reports; however, the rates of MRSA associated with the reporting facilities in BC were relatively stable since FY 2010/2011, and the provincial average rates were lower than the national average. The MRSA cases in this report represented the first identification of MRSA either as infection or as colonization among inpatients by each HA. A prevalence survey found that about 1.5% of the general population may carry MRSA without experiencing any clinical symptomsj, and MRSA colonization can persist for more than four yearsk. With widespread implementation of MRSA screening practices in Canadian hospitals, more MRSA cases, especially colonization, are likely to be identified by the admission screening. On the basis of MRSA surveillance in Canadian hospitalsh, it is estimated that about two-thirds of the MRSA cases were colonizations. MRSA colonization is a strong risk factor for subsequent infection in both community and hospital settingsl. The main objective of this report is to provide a provincial overview of MRSA that can be used to monitor provincial trends and patterns of MRSA over time. The data displayed in the report represent newly indentified MRSA cases only, and should not be interpreted as a performance indicator of the facility. Higher rates of MRSA do not imply that a facility performed poorly in infection control, or against other performance measures. Instead, those hospitals may have more patients vulnerable to MRSA, and/or may be more aggressive in MRSA screening. HCA MRSA was defined based on the patient’s encounter history with healthcare services in the past twelve months. The MRSA classified as associated with the reporting facility was not necessarily acquired in that facility, or even due to healthcare services. MRSA can circulate freely in the community; thus some of the MRSA cases classified as HCA may in fact have been contracted in the community. Recent research shows that certain MRSA

f St. Joseph’s General Hospital (VIHA) did not provide MRSA surveillance data. g Cimolai N (2010). Canadian Journal of Microbiology 56:89-120 h Public Health Agency of Canada (2011). Result of the surveillance of Methicillin-resistant Staphylococcus aureus – from 1995 to 2009 — A project of Canadian Nosocomial Infection Surveillance Program (CNISP). http://www.phac-aspc.gc.ca i Provided by Leslie Forrester, a regional epidemiologist at Vancouver Coastal Health and a member of Data Quality Working Group of Canadian Nosocomial Infection Surveillance Program (CNISP), and Dr. Elizabeth Bryce, Regional Medical Director for Infection Control at Vancouver Coastal Health and co-chair of CNISP j Gorwitz, RJ, et al (2008). The Journal of Infectious Diseases 197:1226-1234 k Robicsek A, et al (2009). Clinical Infectious Diseases 48:910-913 l Wertheim H, et al (2005). The Lancet Infectious Disease 5:751-762

Provincial Infection Control Network of British Columbia (PICNet) 10 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

strains that were previously more prevalent in the community are now frequently identified as the pathogens from the cases of HCA MRSAm,n. In addition, the rates of MRSA in this report were not adjusted for known risk factors and/or screening practices; for this reason, comparisons between Health Authorities and between facilities should not be made. Other limitations to this report are described below (see “Limitations” in the “About this report” section). Acknowledgements

PICNet wishes to thank all participants in each HA and their affiliated healthcare facilities for their ongoing support and participation in our provincial HAI surveillance program.

m Klevens RA, et al (2007). The Journal of the American Medical Association 298: 1763-1771 n Wilmer A, et al (2011). Infection Control and Hospital Epidemiology 32:1227-1229

Provincial Infection Control Network of British Columbia (PICNet) 11 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

About this report

MRSA surveillance system The provincial MRSA surveillance system involves the voluntary participation of 79 of BC’s 80 acute care facilities. The objectives of the system are to monitor the incidence of MRSA (either infection or colonization) and to describe characteristics of MRSA in BC acute care facilities. The PICNet Surveillance Steering Committee determines the core data elements for the provincial MRSA surveillance in order to minimize the burden of data collection. Working with each Health Authority, PICNet collects and manages the aggregated MRSA surveillance data at the provincial level.

Population under surveillance The population under surveillance consists of inpatients in acute care facilities in BC. This includes patients admitted to the emergency department awaiting placement (e.g. patients admitted to a service who are waiting for a bed), patients in alternative level of care beds, patients in psychiatric beds, and patients in labour and delivery beds.

Excluded are outpatient visits to acute care facilities, patients in extended care beds housed in acute care facilities, and patients with short-term emergency room admissions.

Data sources This report incorporates the data collected from 79 acute care facilities in IHA, FHA, VCHA, PHC, VIHA, NHA, PHSA, and their affiliated hospitals. Data on individual MRSA cases are collected daily and managed by each HA. Based on the minimal dataset as defined by the PICNet Surveillance Steering Committee, the HAs submitted aggregated quarterly data of MRSA cases and facility-specific denominators to PICNet. PICNet consolidates the data for provincial analysis and reporting. Updates and modifications submitted after the data submission due dates may not be reflected in this report, but will be presented in future reports.

Limitations The data in this report are subject to limitations. First, the intensity of MRSA screening varies from hospital to hospital, which greatly affects the identification of MRSA. The hospitals which conducted more intense screening of patients (such as general admissions, admissions to ICU and specialty wards, and high-risk patients) may find more MRSA cases than those which screen patients in specific situations only. The laboratory methods used in identifying MRSA and antibiotics tested may also differ by hospital. Second, MRSA colonization and MRSA infection were not distinguished in the surveillance. All newly identified MRSA cases, either colonizations or as infections, were reported. Not included were infections developed after colonizations; infections and/or colonizations identified in different body sites or from another strain of MRSA; re-infections; or re-colonizations. This report may therefore underestimate the magnitude of MRSA in BC acute care facilities. Also, hospitals that conduct wide screening of MRSA may

Provincial Infection Control Network of British Columbia (PICNet) 12 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

report more cases of MRSA colonizations, while hospitals screening patients at high-risk only may have a higher proportion of MRSA infections.

Third, information on previous exposures to healthcare services is used to determine whether the MRSA was healthcare-associated. The ability to determine healthcare encounter history relies on the patient information system used in each hospital and HA. Some misclassification of MRSA is inevitable. In addition, there is some variation in how MRSA was classified by HA. A twelve-month look-back period and three calendar days after admission (with the day of admission counted as the first day) to classify MRSA associated with the reporting facility is employed by all HAs except PHC, which uses more than seventy-two hours after admission and a four-week look-back period. For MRSA identified less than three calendar days after admission to be classified as HCA with the reporting facility, the current case definition requires that the previous admission in the past twelve months must be a period of greater than three days in the healthcare facility. Variations exists in this classification, including FHA, VCHA and VIHA, which employ more than forty-eight hours of admissions in the past twelve months; PHC, which employs more than twenty-four hours; and PHSA, which employs any admissions. Also, IHA and PHSA classify all MRSA cases other than those associated with the reporting facility as “Community- associated” or “Unknown”, including those cases associated with another facility. PHC classifies the HCA MRSA cases that were associated with the facilities within PHC only, and all others as “Not PHC- associated.” Last, the data for MRSA cases were collected by infection control professionals using data collection forms designed by each HA, while the denominators were collected from their information system. Double-reporting may occur if the MRSA was identified by a different HA. In addition, the definition and inclusion criteria of the data field may vary among HAs. Both MRSA cases and denominator data were aggregated by HA at the facility level by fiscal quarter with the exception of PHSA, which aggregated the data by calendar quarter. Excluded from this report were the data for NHA in FY 2010/2011 because a standard case definition for MRSA surveillance was not in place in NHA prior to April 1, 2011. The data for some facilities in IHA were not available for certain periods due to information system upgrades.

Due to unique challenges in the populations served and environment faced by each facility, the HA is best situated to respond to MRSA in their region and their affiliated healthcare facilities.

Provincial Infection Control Network of British Columbia (PICNet) 13 MRSA surveillance report (Quarter 1, FY 2010/2011 – Quarter 2, FY 2011/2012)

Glossary

Acute care facility Acute care facilities are healthcare facilities in which patients are treated for brief but severe episodes of illness, for the sequelae of an accident or other trauma, or during recovery from surgery. In this report, acute care facility refers to acute care hospitals in BC.

Colonization Colonization is the presence of MRSA on tissue without observable clinical symptoms or immune reaction. Common sites of colonization include the nostrils, belly button, underarms, groin, etc.

Community-associated (CA) (Not healthcare-associated) • An MRSA case (as defined above) identified three calendar days or less after admission to an acute care facility, with the first day counted as the day of admission, AND • There was no exposure to any health care facility, either as an inpatient or an outpatient, within the last 12 months.

Confidence Interval (CI) A confidence interval gives an estimated range of values which is likely to include an unknown population parameter to indicate the reliability of an estimate. The 95% CI of the rate and proportion in this report are calculated using Wilson score intervals.o

Fiscal Quarter and Calendar Quarter Fiscal quarter (FQ) is a specified period within a budget or financial year. There are four FQs in a fiscal year. Start and end dates of each FQ vary from year to year. Calendar Quarter is a period of three consecutive months starting on the first day of January, April, July or October. Below are the start and end dates of each quarter for the fiscal year from 2009/2010 to 2011/2012: Start and end date of quarters for this report Fiscal quarter Calendar quarter Fiscal year Quarter code Start date End date Start date End date 2010/2011 Q1 01-Apr-2010 24-Jun-2010 01-Apr-2010 30-Jun-2010 Q2 25-Jun-2010 16-Sep-2010 01-Jul-2010 30-Sep-2010 Q3 17-Sep-2010 09-Dec-2010 01-Oct-2010 31-Dec-2010 Q4 10-Dec-2010 31-Mar-2011 01-Jan-2011 31-Mar-2011 2011/2012 Q1 01-Apr-2011 23-Jun-2011 01-Apr-2011 30-Jun-2011 Q2 24-Jun-2011 15-Sep-2011 01-Jul-2011 30-Sep-2011 Q3 16-Sep-2011 08-Dec-2011 01-Oct-2011 31-Dec-2011 Q4 09-Dec-2011 31-Mar-2012 01-Jan-2012 31-Mar-2012

o Agresti A and Coull BA (1998). The American Statistician 52:119-126

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Fiscal Year (FY) A term used to differentiate a budget or financial year from the calendar year. The Fiscal Year in BC runs from April 1 of the prior year through March 31 of the next year. For example: FY 2010/2011 is from April 1, 2010 to March 31, 2011.

Healthcare-associated with reporting facility • An MRSA case identified greater than three calendar days after the patient was admitted to the reporting acute care facility, with the first day counted as the day of admission. OR • An MRSA case identified three calendar days or less after admission to your acute care facility, with the first day counted as the day of admission, AND the patient was admitted to the same acute care facility for a period of greater than 3 calendar days within the last 12 months.

Healthcare-associated with another facility: • An MRSA case identified 3 calendar days or less after admission to the reporting acute care facility, with the first day counted as the day of admission, AND • The case had an encounter with another healthcare facility, either as an inpatient (including Acute Care and Long Term Care), OR as an outpatient (including emergency care, ambulatory care, and outpatient clinics), within the last 12 months.

Health Authority (HA) A Health Authority manages and delivers healthcare services. There are five regional Health Authorities which govern, plan, and coordinate services regionally within 16 health service delivery areas, and a Provincial Health Services Authority which coordinates and/or provides provincial programs and specialized services. The six HAs in BC are: • Interior Health Authority (IHA) • Fraser Health Authority (FHA) • Northern Health Authority (NHA) • Vancouver Coastal Health Authority (VCHA) • Vancouver Island Health Authority (VIHA) • Provincial Health Services Authority (PHSA)

Infection Infection refers to the invasion of bacteria into tissue with the manifestation of clinical symptoms of infection, such as increased white blood cell counts, fever, lesions, furuncles, drainage from a break in skin continuity, or erythema. Infections require treatment.

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Inpatient day An accounting unit used by healthcare facilities and healthcare planners. Each day represents a unit of time during which the services of the institution or facility are used by a patient; e.g. 50 patients in a hospital for 1 day would represent 50 inpatient days.

Methicillin-Resistant Staphylococcus aureus (MRSA) Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staph bacteria that is resistant to certain antibiotics called beta-lactams. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. PICNet’s MRSA surveillance program focused on newly identified MRSA cases, which must meet ALL of the following criteria:

• Laboratory identification of MRSA, including Staphylococcus aureus cultured from any specimen that tests oxacillin-resistant by standard susceptibility testing methods; or by a positive result for penicillin binding protein 2a (PBP2a); or molecular testing for mecA. Positive results of specimens tested by other validated polymerase chain reaction (PCR) tests for MRSA may also be included • The patient must be admitted to an acute care facility • The MRSA must be newly identified at the time of hospital admission or identified during hospitalization, either as infection or colonization This includes:

• MRSA infection or colonization identified for the first time during their hospital admission • Patients identified in the emergency department and then admitted to the reporting acute care facility • Patients that have been identified as being positive for MRSA in outpatient clinics (including ambulatory care) or other health care facilities were admitted to the reporting acute care facility with MRSA This DOES NOT include:

• Patients that were previously identified as being positive for MRSA in the reporting acute care facility or other acute care facilities before current admission • Cases identified in the emergency department or outpatient clinics but are not admitted to the reporting acute care facility • Cases re-admitted with MRSA • MRSA cases transferred from another acute case facility

Nosocomial infection Infection associated with admission to the reporting healthcare facility.

Rate for MRSA associated reporting facility per 10,000 inpatient days Number of new MRSA associated with Rate per 10,000 inpatient days = reporting facility within a defined period x 10,000 Sum of inpatient days during the same period A defined period can be a quarter or several quarters, or a year (annual rate).

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Standard error (SE) Standard error is a statistical term that measures the accuracy with which a sample represents a population. SE reflects how certain the same results would be when obtained from repeated samples. The standard error is most useful as a means of calculating a confidence interval. For a large sample, a 95% confidence interval is obtained as the values 1.96×SE either side of the mean.

Statistical significance In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. In this report, the difference is considered as statistically significant if the 95% confidence intervals of the two rates, proportions, percentages, or means do not overlap (i.e., the lower limit of one confidence interval is greater than the upper limit of the other confidence interval).

Trend test Trend test is an aspect of statistical analysis that tries to determine whether there is a statistically significant trend upwards or downwards over a period of time or among specific ordinal categories. This report uses Mantel-Haenszel Chi-square test for linear trend at a statistically significant level of p < 0.05.

Unknown association A MRSA case where there is insufficient information on healthcare exposure history to classify as a healthcare-associated case or community-associated.

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Surveillance Steering Committee The Provincial Infection Control Network of British Columbia (PICNet) is a provincially supported professional collaborative that provides guidance and advice on healthcare-associated infection prevention and control in British Columbia. Under the aegis and accountability framework of the Provincial Health Services Authority, PICNet connects health care professionals from across the province to develop and create guidelines and tools, with a focus on surveillance, education, and evidence-based practice. PICNet’s Surveillance Steering Committee provides guidance to PICNet’s surveillance programs and assists the PICNet Management Office in implementation within the participating Health Authorities. • Jun Chen Collet, Provincial Health Services Authority • David Crawford, Interior Health Authority • Tara Donovan, Fraser Health Authority • Leslie Forrester, Vancouver Coastal Health Authority • Bruce Gamage (Chair), PICNet • Dr. Guanghong Han, PICNet • Deanna Hembroff, Northern Health Authority • Dr. Bonnie Henry, Provincial Health Services Authority • Dr. Linda Hoang, Provincial Health Services Authority • Anthony Leamon, Vancouver Island Health Authority • Dr. Elisa Lloyd-Smith, Providence Health Care • Anne Marie Locas, Interior Health Authority

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