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Update: Ralstonia Species Associated with Vapotherm Oxygen Delivery Devices --- United States, 2005

This report updates information on Ralstonia species associated with Vapotherm oxygen delivery devices (Vapotherm Inc., Stevensville, Maryland) (1). CDC has obtained new information from a test developed by CDC and performed by The Children's Hospital of Philadelphia (Pennsylvania) to assess the efficacy of the new chlorine dioxide disinfection protocol recommended by Vapotherm. Although limited, this information suggests that the new protocol for disinfecting Vapotherm devices and cartridges might not achieve sustained bacterial control in certain situations. At this time, the optimal protocol to disinfect machines and cartridges that might contain very heavy biofilms is not known.

Before development of the new disinfection protocol in October 2005, certain institutions had reported no growth of Ralstonia spp. in samples obtained from machines and cartridges disinfected according to the previous protocol. In addition, in an experiment conducted by an independent laboratory contracted by Vapotherm, a laboratory-generated biofilm (consisting of a mix of organisms) was grown in a Vapotherm device and cartridge for 3 weeks. The device and cartridge were then subjected to the new chlorine dioxide disinfection protocol. Results from this trial revealed no growth during the 4 days after disinfection.

However, in a single trial designed by CDC and involving one machine, The Children's Hospital of Philadelphia subjected a Vapotherm device and used filter cartridge to the new chlorine dioxide disinfection protocol. The device and cartridge were known to be contaminated with Ralstonia spp., and the unit had been out of service and not disinfected for multiple weeks. Samples obtained immediately after disinfection grew no organisms. The trial was initially designed to run for 30 days; however, after 7 days of continuous operation of the unit with no patient contact, samples from both the vapor condensate and the filter cartridge grew Ralstonia spp. in culture at CDC.

Whether the presence of an unusually heavy biofilm in the machine and cartridge in the hospital experiment resulted in the failure to eradicate Ralstonia spp. is unknown. Similarly, the impact of testing a laboratory-generated biofilm instead of a use-generated biofilm is not known. The varying results achieved with the new disinfection protocol might indicate that its efficacy depends on the maturity of any biofilm contained within Vapotherm machines or cartridges.

Testing is being conducted by a private laboratory and CDC to further assess the efficacy of and possible improvements to the new disinfection protocol; CDC continues to search for the source of Ralstonia spp. contamination in Vapotherm devices. Clinicians should continue to weigh the potential risks for Ralstonia spp. contamination of Vapotherm devices against the benefits of using the device in patients requiring humidified oxygen therapy.

Clinicians are encouraged to report findings of Ralstonia spp. in patients using any Vapotherm 2000 respiratory gas administration device directly to the device manufacturer, local or state health departments, or CDC by telephone, 800-893-0485. Cases or any other adverse events related to medical devices should be reported to MedWatch, the Food and Drug Administration's voluntary reporting program online at; by telephone, 800-FDA-1088; by fax, 800-FDA-0178; or by mail, MedWatch, Food and Drug Administration, HF-2, 5600 Fishers Lane, Rockville, MD 20857.

Reported by: The Children's Hospital of Philadelphia, Pennsylvania. Div of Healthcare Quality Promotion, National Center for Infectious Diseases, CDC.


  1. CDC. Ralstonia associated with Vapotherm oxygen delivery device---United States, 2005. MMWR 2005;54:1052--3.

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Date last reviewed: 11/2/2005


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