Effective cohorting and "superisolation" in a single intensive care unit in response to an outbreak of diverse multi-drug-resistant organisms.

BACKGROUND: Cohorting patients in dedicated hospital wards or wings during infection outbreaks reduces transmission of organisms, yet frequently, this may not be feasible because of inadequate capacity, especially in the intensive care unit (ICU). We hypothesized that cohorting isolation patients in one geographic location in a single ICU and using enhanced isolation procedures ("superisolation") can prevent the further spread of highly multi-drug-resistant organisms (MDRO). METHODS: Six patients dispersed throughout our Surgical Trauma Burn ICU had infections with carbapenem-resistant, non-clonal gram-negative MDRO, namely Klebsiella pneumoniae, Citrobacter freundii, Stenotrophomonas maltophilia, Aeromonas hydrophilia, Proteus mirabilis, Pseudomonas aeruginosa, and Providencia rettgeri. Five of the six patients also had simultaneous isolation of vancomycin-resistant enterococci (VRE). Under threat of unit closure and after all standard isolation procedures had been enacted, these six patients were moved to the front six beds of the unit, the front entrance was closed, and all traffic was redirected through the back entrance. Nursing staff were assigned to either two isolation or two non-isolation patients. In accordance with the practice of Semmelweis, rounds were conducted so as to end at the rooms of the patients with the most highly-resistant bacterial infections. RESULTS: A few months after these interventions, all six patients had been discharged from the ICU (three alive and three dead), and no new cases of infection with any of their pathogens (based on species and antibiogram) or VRE occurred. The mean ICU stay and overall hospital length of stay for these six patients were 78.3 days and 117.2 days respectively, with a mortality rate of 50%. CONCLUSION: Cohorting patients to one area and altering work routines to minimize contact with patients with MDRO (essentially designating a "high-risk" zone) may be beneficial in stopping patient-to-patient spread of highly resistant bacteria without the need for a dedicated isolation unit.