Surveillance for Carbapenemase-Producing Bacteria in the Wake of a Nosocomial Outbreak
Methods: From 1/2012 through 3/2014, perirectal swabs were collected: on admission and weekly in the ICU and other high-risk wards, from patients recently hospitalized at other institutions or transferred out of the ICU, and monthly on all medical-surgical inpatients. Starting 9/2013, swabs were collected from all patients admitted to non-behavioral health wards. Swabs were plated onto chromogenic CRE-selective media and incubated at 35°C for 18-24 h; or tested by blaKPC PCR. Environmental surfaces were sampled using moistened gauze pads. Pigmented colonies were identified by MALDI-TOF MS and tested by blaKPC PCR. CRE-colonized patients were isolated with dedicated nursing and 24-hour infection control adherence monitoring. Equipment and rooms were disinfected with bleach, hydrogen peroxide vapor, and/or UV light.
Results: Of 13,762 orders for surveillance swabs, 11,754 swabs from 3,843 patients were collected, an 85% compliance rate, with the gap largely due to patient refusal. Most swabs were cultured (95.8%), with 4.2% tested directly by PCR. Among 15 patients who had newly identified CRE isolates, 11 were KPC+, of whom 1 had acquired the outbreak strain, and 4 isolates had other mechanisms of carbapenem resistance. Since 7/2012, no instances of hospital transmission have been detected. Of 343 environmental samples, 12 (4.4%) grew CRE (9 sink drains, 1 faucet aerator, 1 handrail, and 1 medication room surface); all but two were epidemiologically linked to colonized patients.
Conclusion: Stringent infection control measures, including direct observation of hand hygiene compliance and aggressive microbiological surveillance were associated with control of CRE transmission. The relative contributions of healthcare personnel and environmental contamination to the nosocomial spread of CRE remain to be delineated.
R. T. Odom,
A. V. Michelin, None
M. A. Bordner, None
A. F. Lau, Bruker Corp: Collaborator, Research support
J. Dekker, Bruker Corp: Collaborator, Research support
K. Frank, Bruker Corp: Collaborator, Research support
D. K. Henderson, None
T. N. Palmore, None
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