C-183. Rapid and Sensitive Detection of Bacterial Cells in Contaminated Platelet Concentrates Using a Newly Developed Bio-imaging System

N. Yamaguchi1, Y. Motoyama2, M. Matsumoto2, N. Kagami2, Y. Tani3, M. Satake4, M. Nasu1;
1Osaka Univ., Osaka, JAPAN, 2Asahi Breweries, Tokyo, JAPAN, 3Osaka Red Cross Blood Ctr., Osaka, JAPAN, 4Tokyo Metropolitan Red Cross Blood Ctr., Tokyo, JAPAN.

Rapid and sensitive methods for the detection of bacterial cells in platelet concentrates (PCs) are required in order to decrease the transfusion-associated risk of infection from bacterially contaminated PCs. In this study, a rapid microbiological method for the sensitive counting of bacteria in PCs was developed by combining a fluorescent staining technique and a bio-imaging system. An esterase indicator, CFDA (carboxyfluorescein diacetate), was used to detect physiologically active bacteria selectively. A newly developed bio-imaging system (μFinder; Asahi Breweries, Ltd.) was used for counting bacterial cells in PCs. The sensitivity, rapidity and recovery rates were evaluated using PCs spiked with bacteria (Bacillus cereus, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saccharolyticus, Streptococcus agalactiae). Discrimination of bacterial cells from platelets was too difficult because of their similar size and shape; thus, we established a pretreatment protocol with enzyme and detergent to remove platelets. Fewer than 10 fluorescent particles were detected by the bio-imaging system following optimized pretreatment and fluorescent vital staining, and this result shows that platelets are selectively digested by pretreatment. Bacterial cells spiked in PCs were detected within 1 hour (pretreatment: 30 min; filtration and fluorescent staining: 15 min; automated counting: 15 min) and the recovery rate of spiked cells was more than 90%. The microbiological method described here is rapid and sensitive, making it particularly useful for the preliminary screening of PCs contaminated with bacterial cells.

131/C. Unusual Organisms and Case Studies

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