Methicillin-Resistant Staphylococcus Aureus (MRSA) Surveillance Report
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MMeetthhiicciilllliinn--RReessiissttaanntt SSttaapphhyyllooccooccccuuss aauurreeuuss ((MMRRSSAA)) SSuurrvveeiillllaannccee RReeppoorrtt Quarter 1, FY 2010/11 – Quarter 2, FY 2011/12 Prepared by: Provincial Infection Control Network of British Columbia (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 hospital 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). Hospitals 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