Near-patient environmental contamination of an intensive care unit with Vancomycin-resistant Enterococci (VRE) and Extended-Spectrum Beta-Lactamase–Producing Enterobacteriaceae (ESBL-E) before and after the introduction of chlorhexidine bathing for patients

In the intensive care unit (ICU), prior room contamination by patients with, for example, vancomycin-resistant Enterococci (VRE), and extended-spectrum β-lactamase–producing Enterobacteriaceae (ESBL-E) is predictive for the acquisition of infections. However, while daily chlorhexidine bathing reduces infection rates due to multidrug-resistant pathogens, the effect of this practice on environmental contamination rates are largely unknown. Surveillance of the healthcare environment is usually only conducted in response to outbreaks along with other infection prevention and control (IPC) investigations and interventions. This is largely due to resource constraints, the transient nature of environmental contamination, low yields from environmental screening, and culture delays, all of which preclude rapid decision making based on these results. In an observational study in a 12-bed adult medical/surgical ICU during non-outbreak periods, we assessed the overall bacterial contamination of near-patient surfaces of occupied beds, includingVRE and ESBL-E, before and after the introduction of a chlorhexidine bathing protocol. A total of 1,703 swabs (Copan E-swabs, Copan Diagnostics, Murrieta, CA) were taken from the immediate environment (within a ~1-m radius) of 157 ICU patients in seven 3-week intervals between October 2012 and June 2014. A chlorhexidine bathing protocol was introduced after period 4 (October 2013). For patient washing, 2% chlorhexidine gluconate cloths, (Sage Products, Cary IL) were universally adopted for use with 100% of ICU patients following a 1-month staff training period. In each 3-week period, 6 ‘high-touch’ sites in occupied beds (Figure 1A) were swabbed twice weekly, as described previously. For some patients, their environment was sampled more than once because their ICU stay exceeded 48 h and because some patients moved beds. Swabs were processed for identification of VRE and ESBL-E among Enterococci and Enterobacteriaceae as described previously. Of 1,703 environmental swabs, 1,186 (70%) were positive for bacterial growth. In total, 176 of 1,186 (14.8%) were positive for Enterococcus spp, of which 61% were VRE, and 49 of 1,186 (4.1%) were Enterobacteriaceae, of which 20% were ESBL-E. Of the 1,703 sites sampled, 745 (43.7%) were taken before chlorhexidine bathing was introduced and 958 (56.3%) were taken after chlorhexidine bathing was introduced. Following the introduction of chlorhexidine cloths for patient bathing, we observed a statistically significant reduction in overall contamination of the environment (74% before vs 62% after; P= .0005, Fisher’s exact test) and in VRE/ESBL-E contamination (9.4% vs 5.0%; P< .0001). The distribution of VRE/ESBL-E between the surfaces sampled before and after chlorhexidine introduction is shown in Figure 1B. A statistically significant reduction in VRE/ ESBL-E was observed for handwashing basins only. Cleaning practices, which involved sequential cleaning of patient bed spaces and general ICU areas with 1000ppm sodium dichloroisocyanurate (Presept®, GS Medical, Dublin, Ireland), were unchanged before and after chlorhexidine bathing was introduced. Hand hygiene audits conducted over the periods in which sampling took place averaged 80.3± 10.5% before chlorhexidine bathing was introduced versus 85.5± 6.5% after chlorhexidine introduction, and the difference was not statistically significant (P= .52, unpaired t test). Data from an ICU annual audit revealed a 15% increase in the number of patients admitted to the unit over the study period; bed-space occupancy increased from 98% to 110% and mean length of stay decreased from 7.0 to 6.3 days. Higher bed occupancy is reported to positively correlate with HCAI rates. Therefore, the reduction in environmental contamination observed following the introduction of chlorhexidine bathing, despite increased pressure on the unit in terms of bed occupancy, is notable. Other potential confounders that may have affected ward activity in the 2 phases included ambient temperature (as a measure of seasonal alterations) and antibiotic consumption. The mean ambient monthly temperature recorded by the nearest weather station (<6km) over the 2 sampling phases and available from the Irish meteorological service MetEireann was lower after chlorhexidine bathing was introduced, but not significantly so (7.9± 0.47°C vs 8.5±0.37°C; P= .70). The ICU ambient temperature was constant between study phases (temperature, 22–24°C; humidity 30–60°C). In addition, ICU antibiotic Cite this article: McDermott H, et al. (2018). Near-patient environmental contamination of an intensive care unit with Vancomycin-resistant Enterococci (VRE) and Extended-Spectrum Beta-Lactamase–Producing Enterobacteriaceae (ESBL-E) before and after the introduction of chlorhexidine bathing for patients. Infection Control & Hospital Epidemiology 2018, 39, 1131–1132. doi: 10.1017/ice.2018.146 Author for correspondence: Dr Deirdre Fitzgerald-Hughes, Department of Clinical Microbiology, RCSI Education and Research Centre, Smurfit Building, Beaumont Hospital, Dublin 9, Ireland. E-mail: dfitzgeraldhughes@rcsi.ie