title: Attomol-level ATP bioluminometer for detecting single bacterium.
abstract: We have developed an automated high-sensitive ATP bioluminometer for detecting single bacterium. The apparatus consists of a tube rack for setting reagents and samples, two washing baths for preventing sample carry-over from dispenser nozzle, and x-, y-, z- actuators for moving the dispenser, and an high-sensitive optical system. The reaction tube was selected to reduce the background signal intensities for the ATP bioluminescence measurement. The background signal intensity of the reaction tube was 18 RLU, which is almost the same as the dark counts of the photomultiplier (16 RLU). The ATP calibration curve was linear from 0 to 5 amol (its slope = 22.4 RLU/amol and 3.3 SD of the blank sample signal = 17.9 RLU), and the detection limit of 0.8 amol was obtained. The relationship between intracellular ATP and CFU in Escherichia coli (ATCC25922) was kept linearity from 0 to 20 CFU, and the intracellular ATP (amol) per CFU was calculated to be 3.3 amol/CFU (R2 = 0.9713). Moreover, the relationship between intracellular ATP and CFU in Staphylococcus aureus (ATCC25923) was also kept linearity from 0 to 30 CFU, and the amol/CFU was calculated to be 1.6 amol/CFU (R2 = 0.9847). The automated ATP bioluminometer has ultra-high sensitivity and will be a powerful tool for measuring ATP luminescence derived from small number of bacteria.
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Okanojo
authors.affiliation: Infrastructure Systems Company, Hitachi Ltd, Tokyo, Japan.
authors.forename: Noe
authors.initials: N
authors.lastname: Miyashita
authors.affiliation: Infrastructure Systems Company, Hitachi Ltd, Tokyo, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Tazaki
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Tokyo, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tada
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Tokyo, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Hamazoto
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Tokyo, Japan.
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Hisamatsu
authors.affiliation: Central Research Laboratory, Hitachi Ltd, Tokyo, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Noda
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000737:chemistry; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods*; D002138:Calibration; D015169:Colony Count, Microbial; D004867:Equipment Design; D004926:Escherichia coli / Q000166:cytology; D057230:Limit of Detection; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus / Q000166:cytology
chemical_list: D000255:Adenosine Triphosphate
keywords: attomol-level ATP; automated luminometer; automated washing; rapid detection; reaction tubes