A long-lasting Sphingomonas paucimobilis outbreak: A potential for pathogens to persist on environmental devices despite disinfection measures.

BACKGROUND: Sphingomonas paucimobilis, an aerobic, non-fermentative, Gram-negative opportunistic bacillus, can colonize everywhere in hospital settings where water is used. We reported a hospital S paucimobilis outbreak that persisted for nearly 2 years despite all necessary preventive measures. METHODS: Over a period from February 13, 2020 to December 3, 2021, 67 patients were identified to have S paucimobilis as documented by positive cultures from clinical samples, along with 19 positive environmental samples. RESULTS: Bacterial regrowth for molecular analysis could be obtained in 49 isolates (39 clinical, 4 extracorporeal membrane oxygenation (ECMO) water heater devices, 1 unused mouthwash solution, 5 water samples from thoracic drainage aspirators). Two distinct clonally indistinguishable genotypes were detected in AP-PCR and PFGE analyses, with 100% consistency. The main cluster was obtained consistently throughout the outbreak from 30 samples (61.2%: 24 clinical, 4 ECMO, 1 unused mouthwash solution, 1 water sample from the thoracic drainage aspirator). The other cluster involved 15 clinical samples and 4 water samples from the thoracic drainage aspirators. CONCLUSIONS: Given that waterborne pathogens can spread to a wide range of equipment used in healthcare environments, the pathogens can persist on the surfaces of environmental devices even after recommended disinfection measures have been applied. Therefore, individual tracking of all devices used in critical care settings, such as thoracic drainage aspirators and ECMO water heater devices, with records of pre- and post-disinfection procedures is of paramount importance for complete elimination of the source of infection.

Stenotrophomonas maltophilia outbreak with a commercial blood gas injector as the culprit and interventions for source and prevention: A possible passage between patient and ECMO water heater device.

BACKGROUND: Despite low virulence of Stenotrophomonas maltophilia, it represents one of the leading drug-resistant bacteria. We report a large outbreak of S. maltophilia infection associated with an unexpected source, which turned out to be a commercial needleless blood gas injector. METHODS: Over a period from January 1 to December10, 2021, 113 patients were identified to have S. maltophilia infection as documented by positive cultures from the clinical samples, extracorporeal membrane oxygenation (ECMO) water heater devices and commercial needleless blood gas injectors. RESULTS: Sixty-seven isolates (59 clinical, 4 ECMO, 4 blood gas injectors) were sent for molecular analysis. Both arbitrarily primed polymerase chain reaction and pulsed-field gel electrophoresis analyses showed 12 distinct genotypes. Of 67 isolates, 58 were clonally related (86.6%), with 52 indistinguishable strains from 4 blood gas needleless injectors, 46 patients' samples (78%), and 2 ECMO samples (50%). Two ECMO samples and 1 clinical sample were clonally identical. CONCLUSIONS: In the event that eradication of infections would not be possible despite taking all environmental disinfection measures including the ECMO devices, unexpected sources, such as a commercial needleless blood gas injector, should not be omitted from the list for surveillance. In addition, obtaining surveillance cultures of ECMO water reservoirs should be placed in the routine clinical practice.