A cluster of hospital-acquired Burkholderia cepacia complex infections was found to be attributed to contaminated extracorporeal membrane oxygenation (ECMO) water heaters. These findings were published in Clinical Infectious Diseases.

In December of 2020, an outbreak B cepacia occurred among patients in the cardiothoracic surgery intensive care unit (CTICU) at Brigham and Women’s Hospital in the United States. A retrospective review of patient records between October 2019 and February 2021 was performed to evaluate the epidemiology of the outbreak.

Among all patients (n=26) who tested positive for B cepacia infection during the study period, 6 infections were confirmed and 2 as probably related with the CTICU cluster, 5 were unrelated with the cluster but treated in the CTICU, and 13 were neither related with to the cluster nor did they receive treatment in the CTICU.


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In addition to the cluster, several non-contaminans species including B cenocepacia (n=8), B multivorans (n=5), B dolosa (n=2), B cepacia/B vietnamiensis (n=1), and Paraburkholderia caledonica (n=1) were detected.

The CTICU cluster cases and unrelated CTICU cases were among patients with a median age of 64 (range, 55-78) and 69 (range, 39-89) years; 50% and 40% were men, median duration on ECMO was 15 (range, 7-18) and 23 (range, 9-37) days until positive culture, 75% and 80% tested positive for infection via respiratory culture, 62.5% and 20% tested positive via blood culture, and 0% and 20% tested positive via urine culture, respectively.

Among patients whose infection was related with the cluster, all had a severe infection that required antibiotic treatment. Of these patients, 3 died during hospitalization, 3 survived but developed chronic colonization and recurrent infection, and 2 recovered.

After cultures were obtained from the water-based ECMO heaters for analysis, all grew B cepacia and were subsequently removed from clinical service. In addition, after cultures were obtained from ECMO water heater touch screens and the sink drain within the room in which the ECMO water heaters were reprocessed, cultures grew B contaminans and clonal B contaminans, respectively. Further investigation showed the potential for cross-contamination between ECMO water heaters via the contaminated sink.

The researchers reviewed the hospital’s ECMO water heater reprocessing protocols and practices. They noted that hospital staff had been disinfecting the water heaters with ortho-phthalaldehyde, a high-level disinfectant not on the approved list of disinfectant agents from the device manufacturer. The researchers also noted that water heaters had been rinsed with tap water rather than sterile water, and sterilization of the water heaters had not been confirmed via test strips.

Following investigation of the outbreak, hospital staff revised their ECMO water heater sterilization protocols to include the use of 5% bleach and manual scrubbing of the water reservoir. However, after multiple sterilization attempts in accordance with these updated protocols, repeat cultures obtained from the ECMO water heaters continued to grow B cepacia. Due to persistent colonization of the contaminated ECMO water heaters despite the additional sterilization efforts, the devices were decommissioned from clinical service.

Between February 2021 and 2022, no new cases of hospital-acquired B cepacia complex infection were detected among patients in the CTICU.

This study was limited as it did not identify the initial colonization event.

These data indicated that water-based ECMO heaters may be a potential reservoir of dangerous biofilms and infection. In regard to the use of ECMO water heaters, the researchers advised hospitals “to review their adherence with manufacturers’ reprocessing requirements, to consider performing routine surveillance cultures of device reservoirs, or to consider waterless strategies to manage vulnerable patients.”

Disclosure: Multiple authors declared affiliations with industry. Please see the original reference for a full list of disclosures.

Reference

Rhee C, Baker MA, Tucker R, et al Cluster of Burkholderia cepacia complex infections associated with extracorporeal membrane oxygenation water heater devices. Clin Infect Dis. 2022;ciac200. doi:10.1093/cid/ciac200