title: Bactericidal effect of γ-radiation with137Cesium in platelet concentrates.
abstract: BACKGROUND
  γ-radiation is a method that was originally designed for inactivation of T lymphocytes in blood and blood components in order to prevent transfusion associated-graft versus host disease (TA-GVHD). Klebsiella pneumoniae, Escherichia coli, Enterococcus faecium and Staphylococcus epidermidis strains are important pathogens in blood banks since they have been related to post-transfusional sepsis. This study was conducted to demonstrate that γ-radiation is effective in reducing the viability of bacteria in platelet concentrates (PC).
  
  
  METHODS
  Klebsiella pneumoniae, E. coli, E. faecium and S. epidermidis strains were adjusted at 101to 106CFU/ml and used in artificial contamination assays in PC. Contaminated platelet concentrates were subjected to γ-radiation with doses of 2500 cGy in a137Cesium irradiator. The average of surviving bacteria at different bacterial concentrations, logarithmic reduction values (LRV) and bacterial death after γ-radiation percentage was calculated.
  
  
  RESULTS
  Escherichia coli and K. pneumoniae were eliminated in 101to 103CFU; in contrast with 104to 106CFU, the LRV were 2.4, 2.6 and 2.6 for E. coli and 3.3, 2.7 and 3.0 for K. pneumoniae strains at 104, 105and 106CFU respectively. For Gram-positive strains, 101CFU in PC, the inactivation post γ-radiation was not completed. Logarithmic reduction values post γ-radiation were 0.8 to 1.2 for E. faecium and S. epidermidis strains respectively.
  
  
  CONCLUSIONS
  γ-radiation cannot be an alternative for the inactivation of pathogens in PC, because of the bacterial concentration and pathogen nature - being resistant to γ-radiation, the Gram-positive bacteria.
authors.affiliation: Centro Nacional de la Transfusión Sanguínea, Av. Othón de Mendizábal 195, Col. Zacatenco, C.P. 07360, Ciudad de México, Mexico. Electronic address: juanmanuelbello81@hotmail.com.
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Bello-López
authors.affiliation: Centro Nacional de la Transfusión Sanguínea, Av. Othón de Mendizábal 195, Col. Zacatenco, C.P. 07360, Ciudad de México, Mexico.
authors.forename: Facundo
authors.initials: F
authors.lastname: Hernández-Rodríguez
authors.affiliation: Centro Nacional de la Transfusión Sanguínea, Av. Othón de Mendizábal 195, Col. Zacatenco, C.P. 07360, Ciudad de México, Mexico.
authors.forename: Julieta
authors.initials: J
authors.lastname: Rojo-Medina
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001792:Blood Platelets / Q000382:microbiology* / Q000528:radiation effects*; D002588:Cesium Radioisotopes / Q000737:chemistry*; D004926:Escherichia coli / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D050296:Microbial Viability / Q000528:radiation effects
chemical_list: D000900:Anti-Bacterial Agents; D002588:Cesium Radioisotopes
keywords: Bacterial contamination; Inactivation; Platelet concentrates; γ-radiation