Emergence of pstS-Null Vancomycin-Resistant Enterococcus faecium Clone ST1478, Canada, 2013-2018

Area of Science:

• Infectious Diseases
• Microbiology
• Public Health

Background:

• Vancomycin-resistant enterococci (VRE) bloodstream infections (BSIs) are a significant healthcare concern.
• Historically, VRE BSIs have been infrequent in Canada.

Purpose of the Study:

• To investigate a recent, sharp increase in VRE BSIs in Canada.
• To identify the specific strain associated with this rise.

Main Methods:

• Retrospective analysis of VRE bloodstream infection rates.
• Molecular typing of Enterococcus faecium isolates.
• Tracking the prevalence of specific sequence types over time.

Main Results:

• A 113% increase in VRE BSIs was observed in Canada.
• This surge coincided with the emergence of Enterococcus faecium pstS-null sequence type 1478.
• The proportion of this specific strain among all tested isolates rose from 2.7% to 38.7% between 2013 and 2018.

Conclusions:

• The emergence of Enterococcus faecium pstS-null sequence type 1478 is strongly associated with the recent increase in VRE BSIs in Canada.
• Continued surveillance and infection control measures are crucial to manage this evolving threat.