Stricter Barrier Precautions Fail to Lower Incidence of Disease- Resistant Infection

Investigators with the STAR*ICU (Strategies to Reduce Transmission of Antimicrobial Resistant Bacteria in Intensive Care Units [ICUs]) trial said it will likely take more than screening, strict hygiene practices, and barrier precautions to prevent the spread of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) within hospital ICUs. Results of the cluster-randomized trial were reported in the New England Journal of Medicine [2011;364(15):1407-1418]. The analysis included data for approximately 3500 patients admitted for ≥2 days to 1 of 18 adult ICUs in the United States between March and August 2006. Of these, 39% (n=2132) were admitted to the 10 ICUs making up the intervention arm and 37% (n=1356) were patients in the 8 ICUs constituting the control group. Shortly after admission, patients underwent cultures for MRSA and VRE, which were repeated weekly and then within 2 days of discharge. Tests showed a median of 46% of intervention patients, and 38% of controls were MRSA positive at admission. Initial VRE cultures were positive for a median of 62% of intervention patients and 77% of controls. Surveillance culture results were withheld from the control ICUs, which used standard protocols to identify infected patients. Many MRSA/VRE colonizations and infections were never detected outside of the cultures. Intervention ICUs used culture results to determine appropriate barrier precautions. Researchers educated ICUs on 3 levels of precautions, all involving a hand-hygiene component before and after contact with patients and their environment, and requiring use of clean gowns and gloves during sterile procedures. Standard precautions were the least restrictive and required that staff members also don clean gloves when anticipating contact with sources of contamination. Universal gloving required that clean gloves also be worn when handling invasive devices or having contact with environmental surfaces. Contact precautions were the most restrictive and added use of a clean gown when coming into contact with infected patients and their environment. In the intervention arm, universal gloving was used with patients whose MRSA/VRE status was undetermined and who had not been treated for MRSA/VRE in the previous year. If cultures were negative, standard precautions were permitted. For patients treated for either pathogen in the prior year or with positive cultures, control precautions were adopted throughout the stay. Control ICUs used standard precautions with all patients except those treated for MRSA/VRE in the past year or identified by staff as harboring MRSA/VRE, in which case control precautions were initiated. Periodic monitoring found intervention staff more likely than control staff to use clean gloves and hand hygiene per protocol following patient contact (47% vs 25%, respectively; P=.02); they were also more likely to use clean gloves (82% vs 72%, respectively) and gowns (77% vs 59%, respectively) with infected patients. In both groups, providers were least likely to follow precautions when contact was limited to the environment. MRSA and VRE rates varied among institutions in both groups. Neither the intervention arm nor the control arm demonstrated significant change from baseline in infection rates, nor did investigators observe a significant difference in the mean incidence of new MRSA and VRE events per 1000 patient-days between the groups (40.4 vs 35.6, respectively; P=.35). The authors said better identification of patients with MRSA/VRE and expanded use of barrier precautions in hospitals are unlikely to reduce transmission of these pathogens effectively. They acknowledged these findings contradicted those of prior studies, which they said had less rigorous designs. Turnaround time for culture results and less-than-ideal adherence to control precautions might have contributed to the trial’s failure to reduce transmissions. The authors noted that their analyses, however, found no inverse relationship between duration and adherence to control precautions and the incidence of new MRSA/VRE events.