Hospital-wide healthcare-associated carbapenemase-producing Enterobacterales outbreak: risks of electric floor scrubbers in catering facilities and kitchens

BACKGROUND

Carbapenemase-producing Enterobacterales (CPE) are associated with poor clinical outcomes and can spread rapidly in healthcare settings. Environmental reservoirs are increasingly recognized as playing an important part in some nosocomial outbreaks.

AIM

To describe the investigation and control of a CPE outbreak, lasting several years, across two separate hospital sites within one organization.

METHODS

Investigation of multiple ward-level CPE cross-transmissions with a number of sporadic cases. Environmental sampling of ward environments, catering facilities and electric floor scrubbers was undertaken.

FINDINGS

Eleven patients over a 19-month period were identified as carrying healthcare-associated New Delhi metallo-beta-lactamase (NDM)-producing Enterobacter cloacae, and a further patient carried NDM Escherichia coli. E. cloacae isolates were indistinguishable on pulsed-field gel electrophoresis typing, supporting acquisition with a single point source. Environmental sampling found contamination of the electric floor scrubbers used for cleaning the hospital catering facilities and in the associated toilets. Standard outbreak response measures achieved control of ward outbreaks. Sporadic cases and hospital-wide cross-transmission were controlled after interventions on the central food-handling unit and by decommissioning affected floor scrubbers. Electric floor scrubbers were found to have the potential to disperse Gram-negative bacteria into the surrounding environment under experimental conditions.

CONCLUSION

This outbreak report demonstrates that catering facilities and kitchens can be involved in widespread healthcare outbreaks of enteric organisms. This is also the first report of the potential role of electric floor scrubbers in causing significant environmental contamination with CPE which may indicate a role in nosocomial transmission.

Environmental contamination and airborne microbial counts: a role for hydroxyl radical disinfection units?

Environmental contamination is thought to play a role in the spread of infection in hospitals and there has been increased interest in novel air disinfection systems in preventing infection. In this study the efficacy of a hydroxyl radical air disinfection system (Inov8 unit) in reducing the number of airborne bacteria was assessed in a clinical setting. Environmental contamination was assessed using settle plates and air samples in three settings: (1) non-clinical room; (2) non-clinical room with defined activity; and (3) single intensive care unit cubicle. A comparison of air counts and environmental contamination rates was made with the Inov8 units on and off. The Inov8 unit produced an overall reduction in both air sample and settle plate counts in each setting (P<0.001, Wilcoxon signed-rank test). There was a mean reduction in air sample counts of 26%, 39% and 55% for settings 1, 2 and 3 respectively. The corresponding reductions in settle plate counts were 35%, 62% and 54%. These results suggest that this type of novel air disinfection may have a role in improving air quality and reducing environmental contamination within clinical isolation rooms. Further work is required to assess the effect on specific pathogens, and to establish whether this will reduce the risks of patients and/or healthcare workers acquiring such pathogens from the environment.