Background: Routine skin cleansing with CHG is an effective strategy to prevent infection and cross-transmission of bacterial pathogens in healthcare settings. Whether daily CHG bathing selects for CHG resistance is unresolved.
Methods: We collected swab samples of patients' skin to monitor minimal inhibitory concentrations (MICs) of CHG for KPC-producing Enterobacteriaceae during a bundled infection control intervention that was conducted in 4 Chicago LTACHs. During the intervention, all patients were bathed daily with CHG. From May 2012 - June 2013, patients who were rectal carriers of KPC and who had received at least three daily CHG baths were evaluated. Cultures were collected using dual Dacron swabs (BBL) from five skin sites: Antecubital fossa, axilla, back, neck, and inguinal area. Swabs were screened for KPC-producing organisms using an ertapenem disk method; blaKPC was confirmed by PCR. Species were identified by MicroScan Walkaway 96 system (Siemens). K. pneumoniae isolates were identified presumptively as multilocus sequence type 258 (ST258) by PCR assay for the ST258-tonB79 cluster. CHG MICs were tested by broth microdilution. For investigation of change in MIC over time, the study period was divided into 4 intervals that were each 3-4 months long and that included approximately equal numbers of observations.
Results: 217 KPC-positive isolates were cultured from 62 patients. 195 (90%) isolates were K. pneumoniae, 13 (6%) Escherichia coli, 4 (1.8%) Enterobacter aerogenes, 3 (1.4%) Providencia stuartii, and 2 (1%) Citrobacter koseri. 119 (62%) K. pneumoniae isolates were members of the ST258 lineage. For K. pneumoniae, the CHG MIC50/MIC90 were 32 µg/mL and 64 µg/mL in periods 1, 3 and 4, and 32 µg/mL and 128 µg/mL in period 2 (Figure). K. pneumoniae ST258 isolates had a significantly higher geometric mean CHG MIC compared to non-ST258 K. pneumoniae (32 µg/mL vs. 18 µg/mL, p=.002). In an analysis of variance that corrected for person and anatomic site, no increase in geometric mean MIC was observed over time among K. pneumoniae , p=.84.
Conclusion: Daily CHG bathing of LTACH patients over 14 months was not associated with development of reduced susceptibility to CHG in KPC-producing K. pneumoniae isolates.
Figure: CHG MICs of blaKPC-positive K. pneumoniae isolates.
N. M. Moore,
L. Fogg, None
S. Weiner, None
D. Blom, None
R. D. Lyles, None
M. Y. Lin, None
D. W. Hines, None
R. A. Weinstein, None
M. K. Hayden, Sage Products, Inc.: Sage provided CHG product at no cost to facilities involved in this study. , Sage provided CHG product at no cost to facilities involved in this study.
Molnlycke: Molnlycke provided CHG product at no charge to facilities participating in a research project on which I am a co-investigator. , Molnlycke provided CHG product at no charge to facilities participating in a research project on which I am a co-investigator.
F. T. CDC Prevention Epicenters Program, None
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