MRSA SCREENING:

THEORETICAL VS. PRACTICAL

Nancy Alfieri, March 5, 2008

Why Screen?

PROs:• MRSA has increased (in CHR) from 2.2 to

9.4/10,000 patient days since 2003

• CMRSA (new cases) is rising as quickly as health-care associated MRSA in the CHR

• U.S. data indicates an MRSA infection costs an additional $35,000 (while other nosocomial infections add $14,000 to $15,000)

• Patients with unidentified MRSA act as reservoirs for transmission

CONs:

• Screening programs are expensive…

$100,000 allows 5,000 persons to be screened (average of 2.5 screens/person)

3 averted infections = $105,000

• Isolation precautions challenge systems already stretched to capacity

CHR Universal Screening Pilot Project

• 3 months, 3 units(orthopedic surgery, palliative/medicine, medical teaching)

• Methods:• All patients admitted to these units were screened

• Prevalence screens conducted prior to beginning screening and on termination of the pilot

• Anatomical sites screened were: – Nasal culture– Z body swab (axilla and torso)– Up to three wounds

• Suppression: CHG bath/shower

Results• 89.2% of eligible patients were screened

PREVALENCE SCREEN RESULTS

FMC (%) PLC (%) RGH (%) Total

Previously unknown MRSA positive patients detected during Prevalence Screen #1 1/37 (2.7) 4/26 (15.3) 0/33 5/96(5.2)

Previously unknown MRSA positive patients detected during Prevalence Screen #2 1/33 (3.0) 2/29 (6.7) 0/27 3/89(3.3)

New Cases Admitted During Pilot

  FMC (%) PLC (%) RGH (%)

Positive screening at admission to study unit 8/445 (1.8) 20/238(8.4) 11/246 (4.5)

Positive clinical isolate* at admission 0 1/238(0.4) 0

Positive clinical isolate >72 hrs in hospital 0 1/238(0.4) 0

Total 8/445 (1.8) 22/238 (9.2) 11/246 (4.5)

Acquisition of Newly Detected MRSA

Positive Cases

  FMC PLC RGH Total (%)

Nosocomial* 3 12 2 17 (41.5)

LTC 1 0 4 5 (12.2)

Community 4 10 4 18 (43.9)

Unknown 0 0 1 1 (2.4)

Total 8 22 11 41 (100.0)

The Last Table is Important! Why?

• An equal number of cases are hospital-acquired and community-acquired

• This means up to 44% of the positive patients would have been “missed” using an admission screening protocol based on previous hospitalization or living in “institutional” settings

What Did We Learn…

• For the CHR, traditional admission screening would not capture a large proportion of the MRSA-colonized clients

• Medically complex patients with multiple co-morbidities and frequent health care encounters are to be considered “high risk” for MRSA

• Some surgical patient populations may be low risk

What did we learn…(cont’d)

• “Universal” screening is challenging to units facing significant staffing shortages

• Housekeeping workload increases as the burden of patients on isolation increases

• Suppression regimes may be an effective way to decrease transmission risk

• Streamlining screening processes is key to sustainability

Next Steps…

• In the CHR we are proposing expansion of the “universal” screening process and staging implementation

• Screening programs require regular analysis for efficiency and effectiveness

• Screening combined with interventions to reduce transmission requires further study

GO OUT ON A LIMB…

Recommendations1. Go ‘out on a limb’, test your population appropriately

2. Engage the front-line care providers and measure workload, transmission/ acquisition rates in screening programs

3. Question, Question, Question….if the screening protocols don’t impact nosocomial acquisition…then what?

4. Test interventions:• Effective screening specimens• Decolonization• Suppression• Isolation• Environmental controls• Hand hygiene