Ralstonia pickettii bloodstream infections with potential genomic link to internationally distributed contaminated...

Area of Science:

• Microbiology
• Infectious Diseases
• Genomics

Background:

• Ralstonia pickettii, a Gram-negative bacterium, can cause severe infections, particularly when contaminating liquid medical products.
• Detection of R. pickettii in patient blood cultures and a stem cell product prompted an investigation into its source.

Purpose of the Study:

• To investigate the source of Ralstonia pickettii infections in three patients.
• To determine the relationship between patient isolates and environmental strains.
• To assess the potential for a common source of contamination in medical products.

Main Methods:

• Whole genome sequencing (WGS) was performed on three patient isolates and two environmental water isolates.
• Core genome multilocus sequence typing (cgMLST) was used for detailed genomic comparison.
• Genomic comparison included a known R. pickettii cluster linked to contaminated saline.

Main Results:

• Patient isolates were closely related to each other but distinct from environmental isolates.
• Patient isolates showed distant relation to an Australian R. pickettii cluster linked to Indian saline.
• Linked medical products were sourced from Europe and the United States, not India.

Conclusions:

• The findings suggest an ongoing risk from an unknown common source of R. pickettii contamination.
• Medical products, potentially distributed globally, may be implicated in this outbreak.
• Investigating invasive R. pickettii infections with WGS is crucial for identifying sources and preventing outbreaks.