title: Evaluation of a novel automated chemiluminescent assay system for antimicrobial susceptibility testing.
abstract: The newly developed Rapid Lumi Eiken/IS60 (RL/IS60) system automatically determines MICs by detecting chemiluminescence produced in the reaction of a chemiluminescent probe and oxygen metabolites from living microorganisms. The present study evaluated this system for accuracy in antimicrobial susceptibility testing. Chemiluminescence intensities after 4 h of cultivation of clinically important strains were plotted against various concentrations of antimicrobial agents, which resulted in curves reflecting the levels of susceptibility. Sixty-percent inhibitory concentrations based on the susceptibility curves agreed with MICs determined by the reference microdilution method. When the MICs of antimicrobial agents for four quality control (QC) strains (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) were determined by the RL/IS60 system, most (91.1%) of them were within the QC limits proposed by the National Committee for Clinical Laboratory Standards. The system was further assessed for a total of 162 clinical isolates, including E. coli, Citrobacter freundii, Enterobacter cloacae, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Morganella morganii, P. aeruginosa, Haemophilus influenzae, S. aureus, coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, and Streptococcus pneumoniae. Overall, there was 90.6% agreement between the RL/IS60 system and the reference microdilution method. Our results suggest that the RL/IS60 system provides rapid and reliable MICs of a variety of antimicrobial agents for clinical isolates as well as QC strains.
authors.affiliation: Eiken Chemical Co., Ltd., Tochigi, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Manome
authors.forename: Masanari
authors.initials: M
authors.lastname: Ikedo
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Saito
authors.forename: Keiko Kumura
authors.initials: KK
authors.lastname: Ishii
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kaku
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001331:Automation; D001419:Bacteria / Q000187:drug effects*; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D008163:Luminescent Measurements; D008826:Microbial Sensitivity Tests / Q000379:methods; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011933:Reagent Kits, Diagnostic; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D011933:Reagent Kits, Diagnostic