Vancomycin-resistant Enterococcus sequence type 1478 spread across hospitals participating in the Canadian Nosocomial Infection Surveillance Program from 2013 to 2018

Abstract

Objective: To analyze the spread of a novel sequence type (ST1478) of vancomycin-resistant Enterococcus faecium across Canadian hospitals. Design: Retrospective chart review of patients identified as having ST1478 VRE bloodstream infection. Setting: Canadian hospitals that participate in the Canadian Nosocomial Infection Surveillance Program (CNISP). Methods: From 2013 to 2018, VRE bloodstream isolates collected from participating CNISP hospitals were sent to the National Microbiology Laboratory (NML). ST1478 isolates were identified using multilocus sequence typing, and whole-genome sequencing was performed. Patient characteristics and location data were collected for patients with ST1478 bloodstream infection (BSI). The sequence and patient location information were used to generate clusters of infections and assess for intrahospital and interhospital spread. Results: ST1478 VRE BSI occurred predominantly in a small number of hospitals in central and western Canada. Within these hospitals, infections were clustered on certain wards, and isolates often had <20 single-nucleotide variants (SNV) differences from one another, suggesting a large component of intrahospital spread. Furthermore, some patients with bloodstream infections were identified as moving from one hospital to another, potentially having led to interhospital spread. Genomic analysis of all isolates revealed close relatedness between isolates at multiple different hospitals (<20 SNV) not predicted from our epidemiologic data. Conclusions: Both intrahospital and regional interhospital spread have contributed to the emergence of VRE ST1478 infections across Canada. Whole-genome sequencing provides evidence of spread that might be missed with epidemiologic investigation alone.

Genetic analysis of vancomycin-variable Enterococcus faecium clinical isolates in Italy

“…Previously, VVE strains lacking the pstS gene have been identified only in the ST1421 clone [ 6 , 10 , 16 ]. To date, VRE ST1478 was only detected across Canadian hospitals by national surveillance [ 24 , 25 ].…”

“…These pstS -null sequence types (e.g., ST1421 and ST1424) have been reported in Australia, Denmark, Scotland, and South Korea [ 16 , 21 – 23 ]. Very recently, a novel pstS -null ST1478 was also disseminated across acute care hospitals in Canada [ 24 , 25 ].…”

Healthcare-associated infections and antimicrobial resistance in Canadian acute care hospitals, 2017–2021

“…bone marrow transplants, solid organ transplants, cancer patients, etc.) (( 41 )). Although there is a lack of recent data on VRE BSI rates in comparable jurisdictions, there have been increasing trends noted in Europe (( 42 – 45 )), which may be associated, in part, with the introduction and spread of a new clone and gaps in infection prevention practises (( 44 – 46 )).…”

Bacteriocin production facilitates nosocomial emergence of vancomycin-resistantEnterococcus faecium

“…We did however note differences in the percentage of isolates residing within putative transmission clusters among different lineages, with lineage ST1478 showing a significantly higher proportion of clustered isolates. Prior literature has found that the ST117 lineage was responsible for numerous VREfm hospital outbreaks 12,14,33 ; however, the ST1478 lineage has only been detected in the US and Canada 19 . Taken together, these findings suggest that some VREfm lineages might be more efficient than others at transmitting between patients in the hospital.…”

“…CC17 strains frequently encode antimicrobial resistance genes, mobile genetic elements, and genes that enable the metabolism of amino sugars found on GI epithelia and mucin, likely contributing to the success of CC17 strains in healthcare settings [12][13][14][15][16][17][18] . This success is exemplified by CC17 lineages being identified as responsible for widespread outbreaks and increased rates of invasive infection 14,15,17,19 . Although several prior studies have investigated VREfm population structure and dynamics within healthcare settings, we know little about the factors that drive the emergence and persistence of particular VREfm lineages in the hospital.…”