Single Nucleotide Polymorphism (SNP) Analyses Reveal Potential Vancomycin-Resistant Enterococci (VRE) Transmission Networks between Rooms and Patients on Stem Cell Transplant (SCT) and Leukemia Units

Abstract

Control CMV reactivation after HCT is highly dependent on CMV-specific T cells. Using 13-color flow cytometry, we studied CD8+ T cell responses to pp65 and IE-1 CMV peptide stimulation in cryopreserved PBMC from three clinically distinct subgroups (n = 10 each) of HCT patients: 1) Elite Controllers (EC): CMV seropositive (R+) recipients who never reactivated CMV based on weekly surveillance testing; 2) Spontaneous Controllers (SC): CMV R+ recipients who spontaneously resolved low-grade viremia without antiviral therapy; and 3) Non-controllers (NC): CMV R+ recipients who experienced high-grade CMV viremia (>1000 IU/mL) requiring antiviral therapy. We identified two CMV-specific CD8+ T cell cytokine signatures, measured at day +30, that were strongly associated with the risk of CMV reactivation (Figure 1): i) the non-protective signature (NPS) consisting of IL-2 neg IFNg pos TNFa neg MIP-1b pos CD8+ T cells was positively associated with CMV reactivation (4.9% of CMV-specific CD8+ T cells vs. 19.4 P = .002 for EC vs. SC/NC; 4.9 vs. 10.8 P = .02 for EC vs. SC; 4.9 vs. 22.8 P = .005 for EC vs. NC for pp65 stimulated cells; similar trends were observed in IE-1 stimulated cells); ii) the protective signature (PS) consisted of quadruple producers (IL-2 pos IFNg pos TNFa pos MIP-1b pos), and was significantly reduced 94

Birth Mode Does Not Determine the Presence of Shared Bacterial Strains between the Maternal Vaginal Microbiome and the Infant Stool Microbiome

“…Studies assessing pathogen transmission in outbreak settings using diagnostic sequencing typically involve thresholds dictating the maximum number of SNPs separating any two given genomes to define transmission events. While thresholds differ by species, the upper bound of whole-genome SNP thresholds is approximately 15 to 25 SNPs ( 35 – 37 ). Overall, pairwise comparison of SNPs between all B. breve genomes recapitulated prior findings of within-dyad relatedness between maternal and infant isolates ( Fig.…”

Update on infection control practices in cancer hospitals

“…WGS has yielded important insights into transmission pathways for several significant pathogens and has revealed outbreaks in situations in which standard infection control surveillance and definitions showed no indications of causative pathogens . In a recent study at MD Anderson using WGS of VRE isolates, we demonstrated potential transmission networks between the patient and the environment within and between rooms as well as between patients within and between floors . The limitations of WGS include the need for effective semiautomated pipelines, standardized quality control and data interpretation, bioinformatics expertise, and the infrastructure's cost …”

“…Emerging disciplines, such as outpatient cancer care and the entailed infection control practices (including up‐to‐date immunizations, community respiratory viruses, and prolonged shedding), the role of antibiotic stewardship, and the use of whole‐genome sequencing (WGS) for outbreak investigations, have great applications in ICP for patients living with cancer. However, there is no clear consensus or guidance on the variety of ICP strategies; recommendations for these practices are mainly center‐adapted .…”