title: A noninvasive near infrared system for detection of platelet components contaminated with bacteria.
abstract: BACKGROUND
  Platelet (PLT) transfusion-associated bacterial sepsis has remained a substantial patient risk, primarily due to lacking effective and point-of-issue measures to detect bacterial contamination. This study describes near infrared (NIR) spectroscopy to examine inoculated PLTs without sampling within a few seconds.
  
  
  METHODS
  This study evaluated apheresis PLTs inoculated with low concentrations of Bacillus cereus and Staphylococcus epidermidis, comparing with sterile bags. Short-wavelength NIR spectra over the range from 700 to 1100 nm in the transmittance mode were obtained using research (NIRS6500, Foss NIRSystems) and portable (NIRGun, Shizuoka Shibuya Seiki) instruments at 6-hour intervals from 0 to 72 hours after inoculation (HAI).
  
  
  RESULTS
  The sensitivity of the NIRS6500 was 100% (43/43) and 98% (50/51) after incubating PLTs inoculated with B. cereus for 42 HAI or more and with S. epidermidis for 54 HAI or more, respectively. Difference spectra calculated by subtracting the NIR spectra of stored PLTs with that of the same PLTs measured at 0 HAI improved the discrimination results compared with conventional second derivative spectra.
  
  
  CONCLUSIONS
  The NIRS6500 system can provide a PLT monitoring system based on difference spectra. The chemical components of PLTs that were influenced by bacterial metabolism seemed to play an important role in the calibration structure. Further studies should examine samples spiked with various species of prevalent bacteria.
authors.affiliation: National Food Research Institute, Tsukuba City, Ibaraki, Japan.
authors.forename: Sirinnapa
authors.initials: S
authors.lastname: Saranwong
authors.forename: Shoji
authors.initials: S
authors.lastname: Ezuki
authors.forename: Kinuyo
authors.initials: K
authors.lastname: Kawabata
authors.forename: Sumio
authors.initials: S
authors.lastname: Kawano
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ohto
mesh_terms: D001409:Bacillus cereus / Q000254:growth & development / Q000302:isolation & purification; D000094902:Blood Banking / Q000379:methods*; D002138:Calibration; D004866:Equipment Contamination; D016908:Gram-Positive Bacterial Infections / Q000097:blood / Q000517:prevention & control / Q000635:transmission; D006801:Humans; D008828:Microbiological Techniques / Q000295:instrumentation* / Q000379:methods; D017713:Platelet Transfusion / Q000592:standards*; D019265:Spectroscopy, Near-Infrared; D013203:Staphylococcal Infections / Q000097:blood / Q000517:prevention & control* / Q000635:transmission; D013212:Staphylococcus epidermidis / Q000254:growth & development / Q000302:isolation & purification*