IntroductionEarly and precise identification of Klebsiella pneumoniae carbapenemase (KPC) is critical for guiding effective treatment and curbing the spread of carbapenem-resistant pathogens. The mainstream detection methods targeting KPC are exclusively qualitative, lacking reliable quantitative approaches. To address the need for a rapid and quantitative method, this study developed a sensitive fluorescence immunoassay.MethodsThe assay employs a sandwich immunoassay format, which utilizes carboxylated magnetic agarose microspheres for capture and time-resolved fluorescent microspheres for detection. It enables quantification of the KPC protein within approximately 1 h. The analytical performance of the assay was systematically evaluated, including its sensitivity, linear range, specificity and accuracy.ResultsUnder optimal experimental conditions, it exhibits a wide linear range (0.25–1000 ng/mL) and a low detection limit of 0.194 ng/mL, and shows no cross-reactivity with other common carbapenemases. Recovery rates in bacterial lysates ranged from 96.7 to 108.4%. Compared to a commercial immunochromatographic test, this method demonstrated superior sensitivity.DiscussionThe primary advantage of this fluorescent immunoassay is its ability to achieve rapid, sensitive and quantitative detection of KPC, which addresses a key limitation of current qualitative methods. Its wide linear range and low detection limit enable precise monitoring of KPC expression level variations, offering a novel tool for the clinical assessment of bacterial resistance burden.
Mao et al. (Wed,) studied this question.