title: First report of the isolation of Lactococcus garvieae from a platelet concentrate in Japan.
abstract: BACKGROUND
  Bacterial contamination of platelet concentrates (PCs) remains a serious problem in transfusion. We have been conducting sterility tests on all PCs rejected by blood centers or hospitals due to abnormal appearances. We recently experienced a case in which discrepant results were obtained between the methods used to identify a bacterial species isolated from a PC, requiring further analyses.
  
  
  METHODS
  Bacteria were isolated from a PC using the BacT/ALERT system and plate culture. The species was identified using biochemical tests and molecular analysis. Phylogenetic trees were constructed using sequences of the 16S ribosomal RNA (rRNA) and superoxide dismutase (sodA) genes from the bacterial isolate and related species. In addition, the isolate was cultured at temperatures of 10°C and below to determine its growth activity at low temperatures.
  
  
  RESULTS
  Biochemical tests determined that the isolate was Streptococcus alactolyticus, whereas molecular analysis determined that it was Lactococcus garvieae. These two species belonged to different clusters on the phylogenetic tree. Similar to L. garvieae, the isolate could grow at 10°C.
  
  
  CONCLUSIONS
  We conclude that the isolate was L. garvieae according to molecular identification and its growth characteristic at 10°C. Molecular analysis enabled the identification of this species, which was difficult to classify by biochemical tests. Blood facilities need to be prepared with multiple techniques, including genetic analysis techniques, for identifying contaminating bacterial species. L. garvieae can grow at 10°C and can contaminate both red blood cell concentrates and PCs; thus, this species should be listed as a cryophilic bacterium that could threaten blood safety.
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.. m-kozakai@jrc.or.jp.
authors.forename: Moe
authors.initials: M
authors.lastname: Kozakai
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.. c-matsumoto@jrc.or.jp.
authors.forename: Chieko
authors.initials: C
authors.lastname: Matsumoto
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Satake
authors.affiliation: Central Blood Institute, Blood Service Headquarters, Japanese Red Cross Society and Kanto-Koshinetsu Block Blood Center, Japanese Red Cross Society, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tadokoro
mesh_terms: D001792:Blood Platelets / Q000382:microbiology*; D058731:Blood Safety; D005798:Genes, Bacterial; D006801:Humans; D007564:Japan; D017045:Lactococcus / Q000235:genetics* / Q000302:isolation & purification*; D058889:Molecular Typing / Q000379:methods; D010802:Phylogeny; D017713:Platelet Transfusion; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics; D013696:Temperature
chemical_list: D012336:RNA, Ribosomal, 16S; D013482:Superoxide Dismutase