Vermamoeba vermiformis resides in water-based heater-cooler units and can enhance Mycobacterium chimaera survival after chlorine exposure.

BACKGROUND

Mycobacterium chimaera colonizes water-based heater-cooler units (HCUs), from which it can spread to patients during surgery. Vermamoeba vermiformis is a free-living waterborne amoeba, which was consistently present within HCUs.

AIM: To determine whether these amoebae can be involved in the persistent presence of M. chimaera.

METHODS

An in-vitro disinfection model.

FINDINGS: Increased survival of M. chimaera was observed after chlorine exposure in the presence of V. vermiformis. Confocal microscopy demonstrated the intracellular presence of M. chimaera in V. vermiformis.

CONCLUSION

In this way, V. vermiformis can contribute to the persistent presence of M. chimaera in HCUs. Cleaning and disinfection protocols should take this phenomenon into account.