Evaluation of a modified cleaning procedure in the prevention of carbapenem-resistant Acinetobacter baumannii clonal spread in a burn intensive care unit using a high- sensitivity luminometer

Background: Enhanced environmental cleaning practices are among the most accepted measures for controlling the spread of carbapenem-resistant Acinetobacter baumannii (CR-Ab). Aim: To evaluate the impact of heightened cleaning on an ongoing CR-Ab outbreak in a burn intensive care unit (BICU) of an Italian teaching hospital, where chlorhexidine-60% isopropyl alcohol was applied as a complementary disinfectant on high-touch surfaces. Methods: Compliance with the microbial limit proposed for the BICU by AFNOR-NF-S90-351 (20 colony-forming units/100cm(2)) was assessed by plate count, and compared with the results obtained with intracellular adenosine triphosphate (ATP) detection. Genotyping was performed using pulsed-field gel electrophoresis. Findings: During the standard cleaning regimen, three out of 23 samples (13%) gave results over the AFNOR limit and five (21.7%) showed unacceptable ATP levels with 100 relative light units/100 cm(2) as the benchmark limit (sensibility 86.4%, specificity 92.2%). Following improvement of the cleaning procedure, only two samples out of 50 (4%) did not satisfy the microbiological criteria and seven (14%) exceeded the ATP limit. In a successive phase, eight of 30 samples collected showed unacceptable results (27%). Conclusions: Adding chlorhexidine-60% isopropyl alcohol as complementary disinfectant proved to be effective for reducing environmental microbial contamination, ATP levels and CR-Ab infection/colonization in patients admitted to the BICU. Real-time monitoring by ATP assay was useful for managing the cleaning schedule and reducing hospital infections, although the calculated values must be interpreted as cleanliness indicators rather than risk indicators. (C) 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.