Sequencing data of Lactococcus Garvieae strain isolated from platelet concentrate

In September 2020, four paediatric onco-hematologic patients received a platelet concentrate from the same adult donor at Bambino Gesù Children Hospital, Rome. Three of four patients experienced L. garvieae sepsis one day after transfusion. The L. garvieae pediatric isolates and the donor's platelet concentrate were retrospectively collected for whole-genome sequencing (WGS) and shot-gun metagenomics, respectively (Illumina HiSeq). By de novo assembly of the L. garvieae genomes, we found that all the three pediatric isolates shared a 99.9% of identity and were characterized by 440 common SNPs. Plasmid pUC11C (conferring virulence properties) and the temperate prophage Plg-Tb25 were detected in all three strains. Core SNP genome-based Maximum Likelihood tree, including publicly available genomes, revealed a phylogenetic relationship, supported by a value of 100, with L. garvieae strains found to affect cows and humans. Microbial reads obtained by the donor's platelet concentrate have been profiled with MetaPhlAn2 (v.2.7.5); among these, 4.85% belonged to Firmicutes, and 0.84% to Streptococcaceae (>97% identity with L. garvieae), confirming the presence of L. garvieae in the platelet concentrate transfusion. These data showed for the first time three episodes of sepsis due to a transfusion-associated transmission of L. garvieae in three pediatric hospitalized hematology patients. This highlights the importance to implement the screening of platelet components with new human defined pathogens for ensuring safety of blood supply, and, more broadly, for surveillance of emerging pathogens.