1680. Contamination of Hydrostatic Shock Controls with Legionella pneumophila in a Bone Marrow Transplant Unit
Session: Poster Abstract Session: Role of the Healthcare Environment in HAIs
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • Legionella in BMTU (2013)_Final_9 22 13.pdf (327.9 kB)
  • Background: Legionellosis is a major concern for stem cell transplant recipients, and the Foundation for Accreditation of Cellular Therapy (FACT) has recommended periodic testing of water for the pathogen in Bone Marrow transplant units (BMTUs). Shortly after a newly constructed BMTU was opened at the UMass Memorial Medical Center, a routine surveillance culture identified Legionella pneumophila serogroup 1 (L. pneumophila) from a shower sample (60 cfu/ml). Although there had been no clinical cases of Legionellosis, 0.2 micron water filters were installed at each outlet throughout the BMTU and an investigation was initiated.

    Methods: Water samples were collected in 250 ml bottles treated with sodium thiosulfate to neutralize any residual disinfectant. Swab samples were collected and transported in sterile polypropylene bottles. Legionellaculture was performed by PathCon Laboratories (Norcross, Georgia).

    Results: Cultures performed on specimens from all water outlets in the BMTU (n=36) identified L. pneumophila in 3 of 8 showers and 1 of 8 sinks (maximum concentration = 780 cfu/ml). Hot water tanks serving the BMTU tested negative. Chlorine concentrations, temperatures and pH levels in BMTU water outlets were appropriate, and no positive cultures were identified at 60 sites outside the BMTU. Despite initiating a water system flushing protocol in the BMTU and disinfecting shower heads/sink aerators, follow up cultures (n=60) 1 month later still identified L. pneumophila in 6 sites. A review of the BMTU plumbing system revealed newly installed electronic faucets and hydrostatic shock controls; upon sampling, 1 of 8 hydrostatic shock controls showed colonization with L. pneumophila serogroup 1, with the highest microbial concentration (400 cfu/swab) noted within the bellows. Retesting in the BMTU 29 days after removal of contaminated hydrostatic shock controls alongside ongoing water system flushes found 1 positive culture (1 cfu/ml) from a sink sample. 11 other samples from water outlets in that same area all tested negative, including 6 locations that were positive prior to removal of the contaminated hydrostatic shock controls.

    Conclusion: Hydrostatic shock controls that may be installed concurrently with electronic faucets can serve as reservoirs for L. pneumophila.

    Isi Obadan, MD, MPH1, Debra Campbell2, Joseph Allen, DSc, MPH3, Matt Fragala, MS, CIH3, Jerry Ludwig, PhD, PE3, Zita Melvin, RN, BSN, CIC4, Deborah Ann Mack, RN, CIC4 and Richard T. Ellison III, MD1,4, (1)Medicine, University of Massachusetts Medical School, Worcester, MA, (2)Environmental Health & Safety, University of Massachusetts Medical School, Worcester, MA, (3)Building Science & Forensics, Environmental Health & Engineering, Inc., Needham, MA, (4)Infection Control, UMass Memorial Medical Center, Worcester, MA


    I. Obadan, None

    D. Campbell, None

    J. Allen, None

    M. Fragala, None

    J. Ludwig, None

    Z. Melvin, None

    D. A. Mack, None

    R. T. Ellison III, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.