Cupriavidus spp. and other waterborne organisms in healthcare water systems across the UK

Cupriavidus pauculus is a rare clinical pathogen, cases of which have been linked to contaminated hospital water systems. An outbreak of three cases of C. pauculus and other waterborne organisms was reported in a Glasgow hospital in 2018. To determine whether Cupriavidus spp. are present in hospital water systems elsewhere in Scotland and the UK, and to ascertain the optimal laboratory methodology for detection. This study also sought to establish where in the water system these organisms are detected, and whether a selective media could be developed for isolation. In addition, water samples were tested for the presence of other Gram-negative waterborne organisms. Water samples were received from 10 UK National Health Service hospitals and from various parts of the water system. Isolates were plated on to tryptone soya agar (TSA) and Pseudomonas isolation agar, and were further identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry and 16S polymerase chain reaction. Cupriavidus spp. were detected in four of 10 hospitals tested, and all five isolates were from the periphery of the water system. All hospitals had evidence of other opportunistic premise plumbing pathogens. Cupriavidus spp. were identified using TSA, with some isolates growing on Pseudomonas isolation agar; as such, they may be detected inadvertently when testing water specifically for Pseudomonas aeruginosa. Isolation of Cupriavidus spp. was not unique to the Glasgow incident, and these bacteria are present in hospital water systems elsewhere in the UK. Water testing in response to clinical cases is recommended. Consideration should also be given to water testing following bacteraemias due to other rare and unusual water-borne pathogens.