Simulated use of the water circuit disinfection device on a Mycobacterium chimaera-contaminated LivaNova 3T Heater Cooler Device: results of mycobacterial and bacterial surveillance.

BACKGROUND

Mycobacterium chimaera-contaminated heater-cooler devices (HCDs) have been associated with mycobacterial infections after cardiac surgery. Infectious aerosols originating from contaminated water within the HCD that are generated during the operative procedure can transmit M. chimaera. The Water Circuit Disinfection Device (WCDD) is a novel methodology by electrolysis to generate disinfectant agents. The use of the WCDD in combination with a factory-new or used LivaNova 3T HCD after deep cleaning by the manufacturer has been reported to keep HCDs free from mycobacterial contamination. Data on the use of WCDD in combination with used LivaNova 3T HCDs are lacking.

METHODS

We equipped a used, formerly M. chimaera-contaminated LivaNova 3T HCD with the WCDD and simulated its use for 8 months. Every two weeks, 20-ml and 50-ml water samples were analysed for bacterial and mycobacterial growth, respectively. We analysed identified bacteria and mycobacteria during the study period and compared proportions of mycobacterial detection before and after installation of the WCDD.

RESULTS

During the 8-month study period, 21 of 30 (70.0%) water samples grew M. chimaera; no other mycobacterial species were detected. Compared to the anteceding 8 months of the corresponding HCD in clinical use with 12 of 17 (70.6%) water samples growing mycobacteria, the proportion of positive samples did not differ (P=1.00). Of the 36 samples collected for microbiological analysis during the study period, 21 (58.3%) grew bacteria, mostly Sphingomonas spp. (10, 27.8%) and Cupriavidus pauculus (4, 11.1%).

CONCLUSIONS

The installation of the WCDD on a contaminated LivaNova 3T HCD was not associated with significant changes in mycobacterial contamination.