When hand hygiene and unit-wide chlorhexidine bathing are performed faithfully in ICUs, universal screening and isolation measures may not be necessary to reduce acquisition of methicillin-resistant Staphylococcus aureus (MRSA), a new study suggests.
Researchers sought to test the effect of rapid screening and isolation of carriers on colonization of resistant bacteria in settings where best standard precautions were already in place. First, they conducted a 6-month baseline assessment of 13 European ICUs. In phase 2, they performed an interrupted time-series study of universal chlorhexidine bathing coupled with hand hygiene improvement for an additional 6 months.
For phase 3, the researchers randomly assigned the ICUs to conventional screening (chromogenic screening for MRSA and vancomycin-resistant enterococci [VRE]) or rapid screening (polymerase chain reaction testing for MRSA and VRE and chromogenic screening for highly resistant Enterobacteriaceae [HRE]). In addition, they took contact precautions with identified carriers. The main study outcome was acquisition of antimicrobial-resistant bacteria per 100 patient-days at risk. Results were published online Oct. 23 by Lancet Infectious Diseases.
The entire study period was between May 2008 and April 2011. A total of 64,997 swabs were analyzed. Mean hand hygiene compliance improved from 52% at baseline to 69% in phase 2 and 77% in phase 3. The median proportion of patients who got chlorhexidine bathing increased from 0% at baseline to 100% in phase 2. Acquisition of resistant bacteria decreased significantly after implementation of phase 2 (weekly incidence rate ratio [IRR], 1.014 in phase 1 to 0.976 in phase 2; P=0.04). The decline appeared to be driven mostly by lowering MRSA acquisition (IRR, 1.042 to 0.925; P<0.001), as there was no significant reduction in VRE or HRE acquisition. In phase 3, there was no further reduction in acquisition of any individual or composite bacteria, and acquisition didn't differ significantly between the conventional screening group and the rapid screening group.
When there was a sustained high level of compliance to hand hygiene and chlorhexidine baths, acquisition rates of resistant bacteria weren't improved by screening and isolation of carriers, the authors wrote. MRSA was especially susceptible to hand hygiene and chlorhexidine baths, they noted. These findings are consistent with recent studies, they added, but may not apply to settings with lower hand hygiene compliance. The fact that no intervention had an effect on HRE acquisition suggests new methods may be needed to control this bacteria, such as selective digestive decontamination, they wrote.