APIC Chapter 13 Journal Club April 15, 2015 Collateral benefit of screening patients for methicillin-resistant Staphylococcus aureus at hospital admission:

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 CICNYU Langone Medical Center

The proverbial 30,000 foot snapshot

• 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

Collateral benefit of screening patients for MRSAAJIC (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


• 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


• 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)


• 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


• 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


• 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


• 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


• 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)


• 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


• 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)

Appraisal Results

• Level III – Non-Experimental Study• Score: B Thank you!

APIC Greater NY Meeting Here

Documents

APIC Chapter 13 Journal Club April 15, 2015 Collateral benefit of screening patients for methicillin-resistant Staphylococcus aureus at hospital admission: