Program Schedule

636
Chlorhexidine (CHG) and mupirocin susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolates in the REDUCE-MRSA trial

Session: Oral Abstract Session: Epidemiology of MRSA and Impact of Control Interventions
Friday, October 10, 2014: 10:45 AM
Room: The Pennsylvania Convention Center: 111-AB

Background: The degree to which targeted or universal decolonization strategies for control of MRSA select for resistance to decolonizing agents is unresolved.

Methods: MRSA isolates were collected during baseline and intervention periods from 74 ICUs in a 43 hospital, 3-arm, cluster-randomized trial of screening and isolation (arm 1), targeted decolonization with CHG and mupirocin (arm 2), and universal decolonization without screening (arm 3) to prevent MRSA infection.   Isolates with CHG MIC >4 mg/L by broth microdilution were deemed non-susceptible. qacA/B carriage was detected by PCR.  High-level (HL) and low-level (LL) mupirocin resistance (MR) was determined by Etest.  Probability of MR by arm and period was assessed using a mixed effects generalized logistic regression model.

Results: 3,362 ICU isolates were analyzed: 737 in baseline and 2625 in intervention periods (Figure 1).  Most isolates were from anterior nares surveillance cultures (72% baseline, 75% intervention).  Median day of culture collection was 1.

CHG MIC50 /MIC90 were 2/4 mg/L in both baseline and intervention and did not differ by arm.  One isolate (arm 1 intervention) was not susceptible to CHG (MIC 8 mg/L, qacA-positive) and expressed LLMR.  Two other isolates also carried qacA; 1 co-expressed HLMR.  1 isolate carried qacB.  

Because arm 3 stopped surveillance cultures during intervention, we restricted MR analysis to clinical isolates (Figure 2).  We did not find a significant difference in change between periods across the arms in all clinical MRSA (p –value for 4 degree of freedom test comparing difference in ORs, 0.098).  In contrast, for clinical MRSA acquired in ICU we found a significant difference- in-differences between arms (p<0.001) due mainly to a steep decline in LLMR in arm 2 (OR 0.008, 95% CL 0.001-0.06).  An increase in LLMR and HLMR in arm 3 was also observed (OR for HLMR: 2.6, 95% CL 0.78-8.4; OR for LLMR: 4.7, 95% CL, 0.63-34).

Conclusion: In the REDUCE-MRSA trial, CHG resistance and qacA/B were rare.  Odds of MR were higher in intervention vs baseline for isolates in the universal decolonization arm compared to other arms.  But, small isolate numbers caused wide CLs which included the possibility of no difference in change from baseline.  Continued monitoring of resistance is needed.

Karen Lolans, BS1, Katherine Haffenreffer, BS2, Taliser Avery, MS3, Ken Kleinman, ScD2, Haiying Li, Pharm. D.4, Rebecca E. Kaganov, BA5, Julie Lankiewicz, MPH2, Julia Moody, MS6, Edward Septimus, MD, FIDSA, FSHEA6, Robert A. Weinstein, MD, FIDSA, FSHEA7, Jason Hickok, RN, MBA6, John Jernigan, MD, MS8, Jonathan Perlin, MD, PhD, MSHA, FACP, FACMI6, Susan S. Huang, MD, MPH, FIDSA9, Richard Platt, MD, MS, FSHEA2, Mary K Hayden, MD, FIDSA, FSHEA10 and Agency for Healthcare Research and Quality (AHRQ) DEcIDE Network and Healthcare-Associated Infections Program and the Centers for Disease Control and Prevention (CDC) Prevention Epicenters Program , (1)Department of Pathology, Rush University Medical Center, Chicago, IL, (2)Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, (3)Department of Population Medicine, Harvard Medical School, Boston, MA, (4)Rush University Medical Center, Chicago, IL, (5)Harvard Pilgrim Health Care Institute, Boston, MA, (6)Clinical Services Group, HCA Inc, Nashville, TN, (7)Internal Medicine, Section of Infectious Diseases, Cook County Health and Hospitals System, Chicago, IL, (8)Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, (9)Division of Infectious Diseases and Health Policy Research Institute, University of California Irvine School of Medicine, Irvine, CA, (10)Department of Internal Medicine, Section of Infectious Diseases, Rush University Medical Center, Chicago, IL

Disclosures:

K. Lolans, None

K. Haffenreffer, Sage Products, Inc.: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, contributed product

T. Avery, Sage Products, Inc.: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

K. Kleinman, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

H. Li, None

R. E. Kaganov, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

J. Lankiewicz, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

J. Moody, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

E. Septimus, sage and molnlyke: received product, provided product for ABATE study
AHRQ, CDC, NIH: Grant Investigator, Grant recipient

R. A. Weinstein, None

J. Hickok, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

J. Jernigan, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

J. Perlin, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

S. S. Huang, Sage Products: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed Product
Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product

R. Platt, None

M. K. Hayden, Molnlycke: Conducting a clinical trial for which contributed product is being provided to participating hospitals, Contributed product
PDI Healthcare, Inc.: Conducted a clinical trial for which contributed product was provided to the participating hospital., Contributed product
Sage Products, Inc.: Conducted a clinical trial for which contributed product was provided to the participating hospitals., Contributed product

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