Two concurrent nationwide healthcare-associated outbreaks of complex linked to product contamination, UK and Ireland, 2010-2023.

Background: Species of the (Bcc) have been implicated in multiple nosocomial outbreaks linked to contaminated water-based products, including liquid soaps, mouthwash, and other non-alcoholic aqueous solutions.

Objective: We describe two substantial healthcare-associated outbreaks of Bcc ( and ) in the United Kingdom and Ireland associated with contaminated products. We highlight the challenges during investigation and mitigation, and provide recommendations.

Methods: A multidisciplinary, multi-stakeholder investigation across both outbreaks was adopted, involving interviews, trawling questionnaires, and targeted product sampling.

Results: There were 153 and 66 confirmed cases in the and outbreaks, respectively. Cases predominantly comprised hospitalized individuals, and 70% of isolates were recovered from an invasive site. The outbreak strain of was isolated from non-sterile ultrasound gel. An analytical study suggested the cluster was also linked to ultrasound gel; however, a disinfectant wipe product was subsequently identified as the source (0-3 single nucleotide polymorphism differences between case and wipe isolates).

Outbreak Control Measures: The affected disinfectant wipes were withdrawn. The ultrasound gel was not recalled but health system procurement was suspended, rapid clinical guidance was produced and a National Patient Safety Alert was issued. Inter-organizational partnership was required to mitigate risks.

Conclusion: Identifying the source of outbreaks associated with contaminated products can be challenging, requiring complex multi-stakeholder interventions. We recommend a low threshold for investigation of Bcc clusters, adopting a multidisciplinary approach to investigation and mitigation, implementing interventions focusing on practice, and prompt product removal to protect patients.