Decontamination of heater-cooler units associated with contamination by atypical mycobacteria.
BACKGROUND
Non-tuberculosis mycobacteria such as Mycobacterium chimaera are found widely in hospital water systems. Invasive M. chimaera infections have recently been attributed to heater-cooler units (HCUs) of cardiopulmonary bypass equipment.


OBJECTIVE
To assess the extent of microbiological contamination within the HCUs and to inform decontamination strategies for reducing the microbial load.


METHODS
Water samples taken from HCUs used at University Hospitals Birmingham for cardiopulmonary bypass surgery were sampled to determine the number of micro-organisms by membrane filtration. Various decontamination processes were used throughout the study, all based on the manufacturer's guidance.


RESULTS
Total viable counts >300cfu per 100mL containing a wide variety of micro-organisms were obtained from water inside the HCUs. Working with the manufacturers, we significantly reduced the microbial load of the water within the HCUs by removing the internal tubing soiled with biofilm followed by a weekly decontamination regimen with peracetic acid.


CONCLUSIONS
A decontamination cycle including an initial replacement of internal tubing with weekly microbiological water samples is required to maintain the water quality within HCUs at an acceptable level.
University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK. Electronic address: mark.garvey@uhb.nhs.uk.
M I
MI
Garvey
University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK.
R
R
Ashford
University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK.
C W
CW
Bradley
Hospital Infection Research Laboratory, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK.
C R
CR
Bradley
University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK.
T A
TA
Martin
Public Health England, National Infection Service, Biosafety, Air and Water Microbiology Group, Salisbury, UK.
J
J
Walker
University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK.
P
P
Jumaa
D058491:Bacterial Load; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D003666:Decontamination / Q000379:methods*; D004864:Equipment and Supplies / Q000382:microbiology*; D005374:Filtration; D006785:Hospitals, University; D006801:Humans; D017053:Infection Control / Q000379:methods*; D009165:Mycobacterium Infections, Nontuberculous / Q000517:prevention & control; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification*; D013530:Surgical Wound Infection / Q000517:prevention & control; D006113:United Kingdom; D014871:Water Microbiology
Cardiopulmonary bypass surgery; Decontamination; Heater–cooler unit; Mycobacterium chimaera; Water