1. APIC Chapter 13 Journal Club April 15, 2015
Collateral benefit of screening patients for methicillin-resistant Staphylococcus aureus at hospital admission: Isolation of patients with multidrug-resistant gram-negative bacteria
Presented by: Steven Bock RN CIC
NYU Langone Medical Center

2. The proverbial 30,000 foot snapshot

4. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Starting Point
All VAMC Hospitals in the United States
All patients admitted to VAMC hospitals in 2009 – 2012 were included in the study
Included 1.6 million acute care admissions to VAMC hospitals
Represented 759,759 unique individual patients
All patients admitted were included in the study, all patients screened for MRSA colonization at admission (or if found positive within the prior year, included as if tested at admission
All patients MRSA + were put on Contact Precautions (colonized and/or infected)
MRSA screening done by nasal swab PCR, typical lab methodology

5. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Purpose, Definitions
Evaluate impact of MRSA colonization on acquisition of multi-drug resistant gram negative rod (MDR-GNB) colonization and/or infection
Optimize use of Contact Precautions for MRSA and MDR-GNB colonized and/or infected patients
Evaluate benefit of MRSA screening (commonly done) as a proxy for screening for MDR-GNB (not usually done)
Project benefits of Contact Precautions on controlling spread of MDR-GNB (as well as MRSA)
MRSA defined as MRSA PCR + using standard lab methods
New MDR-GNB defined as GNR resistant to at least one drug in 3 different classes of antibiotics, ESBL +, and/or CRE found using standard lab methods, within 30 days of admission

6. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Design
Retrospective review of patient records in national database of all VAMC acute care patients (no control group)
All patients MRSA + in previous 12 months and/or found to be MRSA + within first 24 hrs of admission were put on Contact Precautions
Mean time between admission and screening results (by PCR) was 12.5 hours
New MDR-GNRs were those cases identified within the first 30 days of an admission; could include patients admitted with MDR-GNB and those who acquired MDR-GNB during admission
Comparison of patients admitted with MRSA who became MDR-GNB + was made to patients who were MRSA-free at admission but later developed MDR-GNB
Study design was IRB-approved

7. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Findings 1
Of 1.6 million admissions (759,759 unique patients), 14.7% (~111,700 pts) were MRSA + on admission screening and/or MRSA + in previous 12 months; all were put on Contact Precautions for duration of admission & any subsequent readmissions for following 12 months. About 648,000 pts were MRSA negative.
6.3% (~47,800 pts) had history of MDRO + in prior year (e.g., VRE or MDR-GNB – other than MRSA)
Total of 17.7% (~134,500 pts) of patients were MRSA/MDRO + at admission or within previous 12 months of admission; all put on Contact Precautions for duration of hospital stay
2.4% of MRSA + patients (~2680 pts) developed new MDR-GNB clinical culture during hospital stay
0.9% of MRSA negative patients (~5830 pts) developed new MDR-GNB clinical culture during hospital stay (difference P<.001)

8. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Findings 2
Various MDR-GNR were found
0.2% were MDR Acinetobacter
1.9% were MDR Enterobacteriaceae
20% of new MDR-GNB + patients were MRSA + on admission
11% of new MDR-GNB + patients were MDRO + in previous 12 months
Net 31% of new MDR-GNB + patients had MRSA or MDRO at admission or in previous 12 months (sensitivity of findings)
About 85% of patients who did NOT get MDR-GNB were MRSA negative (specificity of findings)
Findings were consistent between VAMC hospitals

9. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Findings 3
Multilevel regression showed that patients MRSA + at admission had an overall 2.5 fold greater risk of becoming new MDR-GNB during hospital stay vs. MRSA negative pts

10. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Conclusions & Discussion 1
Being MRSA + increases risk of acquiring new MDR-GNB infection
Other studies have shown patients may be co-colonized at admission to acute care hospitals or LTCFs with MRSA & other MDROs (e.g., MDR-GNR).
Screening at admission, if done, is usually limited to MRSA
Lack of MDR-GNR screening at admission may lead to these patients not getting placed on Contact Precautions
Patients put on Contact Precautions for MRSA nasal colonization may help prevent these patients from becoming an undetected reservoir of MDR-GNB

11. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Conclusions & Discussion 2
MRSA screening with the use of Contact Precautions may help “identify” patients who may have MDR-GNB without any additional screening cost or effort
Admission-based MRSA screening with Contact Precautions may help protect a facility from spread of unrelated MDRO
Empiric therapy for MRSA + patients may need to be broadened to cover possible MDR-GNR not yet identified
Empiric therapy for MRSA – patients may be more narrow than traditionally prescribed; they probably don’t have MDR-GNR (~85%)
Cohorting MRSA + patients in the same room should be done cautiously as they may be co-colonized/co-infected with different MDR-GNRs

12. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Limitations & Strengths 1
Study done in VAMC hospitals, unique patient population
MRSA + patients (at admission) may have multiple comorbidities, increasing risk for acquiring MDR-GNB; not controlled in this study
MRSA + patients may get cultured more often than MRSA - patients
MRSA + patients may have been given additional or more broad-spectrum antibiotics, increasing risk of patient developing MDR-GNR infections *
MDR-GNRs identified within 30 days of admission were actually new (not present on admission)

13. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Limitations & Strengths 2
Positive MDR-GNR cultures were assumed to all be infection and not just colonization; however patients would be put on Contact Precautions for either condition
No outcome of acquiring MDR-GNR was made (e.g., longer hospital stay, increased risk of death)
Can’t generalize if Contact Precautions policies are different*
Extremely large sample size
National data set
Robust MRSA screening program
National uniform EMR database from which to collect data

14. Collateral benefit of screening patients for MRSA AJIC (43) January 2015
Study Limitations 1
Study done in VAMC hospitals, unique patient population
MRSA + patients (at admission) may have multiple comorbidities, increasing risk for acquiring MDR-GNB; not controlled in this study
MRSA + patients may get cultured more often than MRSA - patients
MRSA + patients may have been given additional or more broad-spectrum antibiotics, increasing risk of patient developing MDR-GNR infections *
MDR-GNRs identified within 30 days of admission were actually new (not present on admission)

16. Appraisal Results Level III – Non-Experimental Study
Score: B Thank you!
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