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Volume 32, Number 3—March 2026

Synopsis

Stenotrophomonas maltophilia Bloodstream Infection Outbreak in Acute Care Hospital, California, USA, 2022–20231

Sana M. Khan, Axel A. Vazquez Deida, Steven Langerman, Jennifer C. Hunter, Rebeca Elliott, Alison Laufer Halpin, Alyssa G. Kent, Paige Gable, Heather A. Moulton-Meissner, Frances C. Knight, Thomas Ewing, Kristen Clancy, Amit Chitnis, Eileen F. Dunne, Dustin Heaton, Barbara Allen, Hillary Metcalf, Munira Shemsu, Kathleen Nava, Suada Abdic, Kiran M. Perkins, Elsa Villarino, Jeffrey Silvers, and Kavita K. TrivediComments to Author 
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (S.M. Khan, A.A. Vazquez Deida, S. Langerman, J.C. Hunter, A. Laufer Halpin, A.G. Kent, P. Gable, H.A. Moulton-Meissner, F.C. Knight, T. Ewing, K. Clancy, K.M. Perkins); Alameda County Public Health Department, San Leandro, California, USA (S.M. Khan, A. Chitnis, E.F. Dunne, D. Heaton, M. Shemsu, K.K. Trivedi); California Department of Public Health, Richmond, California, USA (R. Elliott, B. Allen, H. Metcalf, E. Villarino); Sutter Health, Sacramento, California, USA (K. Nava, S. Abdic, J. Silvers)

Main Article

Figure 2

Phylogeny of Stenotrophomonas maltophilia detected in bloodstream infection outbreak in acute care hospital, California, United States, 2022–2023. Case-patient numbering starts at 4 because isolates for the first 3 cases were unavailable for sequencing. Full circles on the phylogenetic tree indicate evolutionary branching in the tree with a high value (n = 1) or strong support for the hypothesis that the branching is true. Cluster 1 (n = 12) differed by 0–4 pairwise high-quality single-nucleotide variants (hqSNVs), across 98.54% of the reference isolate core-genome. Cluster 2 (n = 5) differed by 1–21 hqSNVs, across 97.56% of the core-genome. Cluster 3 (n = 2) differed by 12 hqSNVs, across 98.68% of the core-genome. Cluster 4 (n = 2) differed by 3 hqSNVs, across 99.01% of the core-genome. Scale bar indicates nucleotide substitutions per site.

Figure 2. Phylogeny of Stenotrophomonas maltophilia detected in bloodstream infection outbreak in acute care hospital, California, United States, 2022–2023. Case-patient numbering starts at 4 because isolates for the first 3 cases were unavailable for sequencing. Full circles on the phylogenetic tree indicate evolutionary branching in the tree with a high value (n = 1) or strong support for the hypothesis that the branching is true. Cluster 1 (n = 12) differed by 0–4 pairwise high-quality single-nucleotide variants (hqSNVs), across 98.54% of the reference isolate core-genome. Cluster 2 (n = 5) differed by 1–21 hqSNVs, across 97.56% of the core-genome. Cluster 3 (n = 2) differed by 12 hqSNVs, across 98.68% of the core-genome. Cluster 4 (n = 2) differed by 3 hqSNVs, across 99.01% of the core-genome. Scale bar indicates nucleotide substitutions per site.

Main Article

1Preliminary results were presented at the Society for Healthcare Epidemiology of America Spring Conference; April 16–19, 2024; Houston, Texas, USA.

Page created: February 06, 2026
Page updated: March 20, 2026
Page reviewed: March 20, 2026
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