Common microbial isolates in an adult intensive care unit before and after its relocation and expansion

Objective: To describe the prevalence of common and clinically relevant microbial isolates before and after the migration of a 24-bed, open plan, adult intensive care unit (ICU) to a new extended design of 32 single rooms, supporting an expanded clinical oncology casemix while continuing all existing clinical services. Design: Retrospective, observational descriptive analysis covering the period 5 May 2014 to 4 May 2018 - the 2 years before and after the ICU relocation on 5 May 2016. Setting: A university-associated, tertiary teaching hospital and state trauma centre in Victoria, Australia. Patients: Adult ICU patients. Main outcome measures: Bacterial isolate frequency and incident rate ratios (IRRs) during the study period. Results: When compared with the old ICU, the incidence rates per 1000 occupied bed-days in the new ICU were lower for bacterial isolates overall (IRR, 0.88; 95% CI, 0.83-0.93), for coagulase-negative staphylococci (IRR, 0.64; 95% CI, 0.55-0.75) and for vancomycin-resistant enterococci (IRR, 0.50; 95% CI, 0.32-0.80). The incidence rates per 1000 occupied bed-days between ICU locations were unchanged for Staphylococcus aureus (IRR, 1.1; 95% CI, 0.91-1.3), extended-spectrum beta-lactamase-producing organisms (IRR, 1.4; 95% CI, 0.78-2.6) and carbapenemase-producing Enterobacterales (IRR, 0.85; 95% CI, 0.11-6.4). Conclusion: Within the limits of a before-after design and clinically directed sampling, relocation to a new ICU with single rooms and a growing oncological patient casemix was accompanied by no overall change in the apparent prevalence of the nosocomial pathogens S. aureus, extended-spectrum beta-lactamase-producing organisms or carbapenemase-producing Enterobacterales. These finding suggest that advanced physical infrastructure, including patient accommodation in single rooms, may play a role in overall safe delivery of critical care.