Outbreak ofRalstonia mannitolilyticabacteraemia in patients undergoing haemodialysis at a tertiary hospital in Pretoria, South Africa

Background Ralstoniaspecies are Gram-negative bacilli of low virulence. These organisms are capable of causing healthcare associated infections through contaminated solutions. In this study, we aimed to determine the source ofRalstonia mannitolilyticabacteraemia in affected patients in a haemodialysis unit. Methods Our laboratory noted an increase in cases of bacteraemia caused byRalstonia mannitililyticabetween May and June 2016. All affected patients underwent haemodialysis at the haemodialysis unit of an academic hospital. The reverse osmosis filter of the haemodialysis water system was found to be dysfunctional. We collected water for culture at various points of the dialysis system to determine the source of the organism implicated. ERIC-PCR was used to determine relatedness of patient and environmental isolates. Results Sixteen patients were found to haveRalstonia mannitolilyticabacteraemia during the outbreak period. We culturedRalstoniaspp. from water collected in the dialysis system. This isolate and patient isolates were found to have the identical molecular banding pattern. Conclusions All patients were septic and received directed antibiotic therapy. There was 1 mortality. The source of theR. mannitolilyticainfection in these patients was most likely the dialysis water as the identical organism was cultured from the dialysis water and the patients. The hospital management intervened and repaired the dialysis water system following which no further casesof R. mannitolilytcainfections were detected. A multidisciplinary approach is required to control healthcare associated infections such as these. Routine maintenance of water systems in the hospital is essential to prevent clinical infections withR.mannitolilytica.