Acquisition of multidrug-resistant organisms among hospital patients hospitalized in beds adjacent to critically ill patients.

Objective: To assess whether patients hospitalized in beds physically adjacent to critically ill patients are at increased risk to acquire multidrug-resistant pathogens.

Design: Cohort study.Setting. Shaare Zedek Medical Center, a 550-bed medical referral center.

Patients: From April to September 2004, we enrolled consecutive newly admitted patients who were hospitalized in beds adjacent to either mechanically ventilated patients or patients designated as "do not resuscitate" (DNR). For each of these patients, we also enrolled a control patient who was not hospitalized in a bed adjacent to a critically ill patient. We collected specimens from the anterior nares, the oral cavity, and the perianal zone at the time of admission and subsequently at 3-day intervals until discharge or death. Specimens were cultured on selective media to detect growth of antibiotic-resistant pathogens, including Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta lactamase (ESBL)-producing Enterobacteriaceae, and vancomycin-resistant enterococci (VRE).

Results: We enrolled 46 neighbor-control pairs. Among neighbors and controls, respectively, the incidence rates for isolation of A. baumannii was 8.3 and 4 isolations per 100 patient-days (relative risk [RR], 2.1 [95% confidence interval {CI}, 0.8-5.2]; P=.12), the incidence rates for MRSA were 1.4 and 2.6 isolations per 100 patient-days (RR, 0.6 [95% CI, 0.1-2.3]; P=.45), the incidence rates for ESBL-producing Enterobacteriaceae were 10.5 and 9 isolations per 100 patient-days (RR, 1.2 [95% CI, 0.6-2.4]; P=.84), the incidence rates for VRE were 4.3 and 4.8 isolations per 100 patient-days (RR, 0.9 [95% CI, 0.3-2.4]; P=1), and the composite incidence rate was 21.7 and 16.2 isolations per 100 patient-days (RR, 1.3 [95% CI, 0.8-2.3]; P=0.3).

Conclusions: In this pilot study, we did not detect an increased incidence rate of isolation of multidrug-resistant pathogens among patients hospitalized in beds adjacent to critically ill patients. Further studies with larger samples should be conducted in order to generate valid data and provide patients, physicians, and policy makers with a sufficient knowledge base from which decisions can be made.