The Epidemiology and Control of Methicillin-Resistant S.aureus (MRSA) over 16 Years at a Large Tertiary Care Canadian Institution
J Burt, M Garcia, BA Jolley, C Kennedy, S Scarrow, H Dedier, J Strauss, W Marshall, I Campbell, J Conly
Introduction
MRSA major nosocomial pathogen
Hospital outbreaks have occurred on world-wide basis
Prevalence varies depending on many factors-size of institution,patients
First appeared late 1960s Europe < 10 years after introduction methicillin
First isolates US in early 1970s
Percentage MRSA from all NNIS hospitals in US rose from 2.4% to 29% between 1975 and 1991
Epidemiology of MRSA Canada through CNISP (23 sentinel hospitals) has increased from 1.5 -3.3 % 1994 - 1996
Presence of MRSA since 1978 plus outbreak 1982-83 and 1991-92 prompted a review of our experience
Background
Curently 1200 bed tertiary care 2-site medical school affiliated institution
Transplantation,oncology,neuroscience and cardiac care are major priorities
Medical and surgical adult care
7 ICUs ;40,000 patients/yr;334000 patient days
Merged Western and General hospitals in 1989
Methods
- Retrospective analysis of Microbiology records 1981-1996
- All MRSA isolates recorded and saved since 1979 (I Campbell)
- Denominators :1981-84(1 month survey);1985-90 (estimate); 1991-96 (annual report)
- Admissions from Health Records
- Susceptibilities 1981-89 Multiscan (semi-automated replicating system) 1989-96 Microscan (increased salt 1990,oxacillin screen plate 4mg/L 1991-present)
- Phage typing-PHL Ministy of Health using standard techniques
- Pulsed field gel electrophoresis (PFGE ) done using sma-1
Nosocomial vs Community Acquired MRSA
1982-83 88% nosocomial with majority phage type 82 and PFGE type A
1993-95 32% nosocomial with no predominant phage or PFGE type
1996 increase of MRSA due to 2 outbreaks of 2 distinct clonotypes , one of which is a slide coagulase negative S aureus which exhibits an increased capacity for transmission
Care of the Patient with MRSA at The Toronto Hospital
- Single room or cohorting
- Maximal barrier precautions for known positive patients(gloves, gowns,masks)
- Dedicated equipment
- Decolonization therapy (2% mupirocin to nares ; 2% chlorhexidene soap)
- Discontinue isolation if negative x3
- Screening of roomates and screening on a unit/ward if >2 cases
Conclusions
- MRSA incidence had not increased in over 15 years until 1996
- Continuing nosocomial cases each year
- An increase in community cases necessitating admission screening
- Maximal barrier precautions continue to be used for MRSA patients and have been associated with low prevalence of MRSA at our hospital for over a decade
Future Plans
- Maintainence of current program and surveillance system
- Empowerment of patient and caregivers re: handwashing and hygiene
- Continued use of decolonization
- Introduction of "EPIC" Program as a manouevre to increase compliance with basic hygienic principles as health care restructuring occurs in Canada
"EPIC" Program
"Evolving practices in infection control" (EPIC)
Multifaceted program with greater emphasis on patient caregiver hygiene
Wide availability waterless antiseptics
Redeployment housekeeping
Case-mix changes on wards
Greater regional integration infection prevention and control
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