Real-time investigation of a Burkholderia cenocepacia bacteraemia outbreak in a Vietnamese intensive care unit

Abstract

Background: The Burkholderia cepacia complex (Bcc), a group of environmentally ubiquitous bacteria, are inherently resistant to antiseptics and antibiotics. Bcc can proliferate in pharmaceutical products, resulting in nosocomial outbreaks. However, Bcc is often dismissed as blood culture contaminants, and precise identification of Bcc species remains challenging in resource-limited settings, leading to under-treatment and delay in outbreak detection. This paper reports the first identified Bcc bacteraemia outbreak in a Vietnamese intensive care unit (ICU). Methods: In June 2023, a Bcc bacteraemia outbreak was acknowledged by the hospital authorities after examination of clinical and microbiological evidence. A comprehensive investigation was performed, encompassing epidemiological and clinical review, environmental sampling, whole-genome sequencing (WGS), and implementation of enhanced infection prevention and control (IPC) measures. Results: The bacteraemia outbreak involved 19 ICU patients between May and August 2023. The causative bacteria were identified as B. cenocepacia belonging to a novel sequence type, and did not carry any acquired antimicrobial resistance genes. Although these organisms were susceptible to the commonly used antibiotics, the outbreak was associated with a high case fatality rate. Three B. cenocepacia isolates were also found in used syringes for drug infusion in three cases, exhibiting a genomic link to the outbreak cluster. Enhanced IPC measures targeting aseptic techniques in handling intravenous medications resulted in termination of the outbreak. Conclusions: WGS plays a crucial role in outbreak control, particularly for under-studied opportunistic pathogens. This work also highlights key gaps in IPC measures, species identification, and treatment of Bcc infections, warranting further research to improve hospital prevention and treatment strategies.