title: Probing minority population of antibiotic-resistant bacteria.
abstract: The evolution and spread of antibiotic-resistant pathogens has become a major threat to public health. Advanced tools are urgently needed to quickly diagnose antibiotic-resistant infections to initiate appropriate treatment. Here we report the development of a highly sensitive flow cytometric method to probe minority population of antibiotic-resistant bacteria via single cell detection. Monoclonal antibody against TEM-1 β-lactamase and Alexa Fluor 488-conjugated secondary antibody were used to selectively label resistant bacteria green, and nucleic acid dye SYTO 62 was used to stain all the bacteria red. A laboratory-built high sensitivity flow cytometer (HSFCM) was applied to simultaneously detect the side scatter and dual-color fluorescence signals of single bacteria. By using E. coli JM109/pUC19 and E. coli JM109 as the model systems for antibiotic-resistant and antibiotic-susceptible bacteria, respectively, as low as 0.1% of antibiotic-resistant bacteria were accurately quantified. By monitoring the dynamic population change of a bacterial culture with the administration of antibiotics, we confirmed that under the antimicrobial pressure, the original low population of antibiotic-resistant bacteria outcompeted susceptible strains and became the dominant population after 5hours of growth. Detection of antibiotic-resistant infection in clinical urine samples was achieved without cultivation, and the bacterial load of susceptible and resistant strains can be faithfully quantified. Overall, the HSFCM-based quantitative method provides a powerful tool for the fundamental studies of antibiotic resistance and holds the potential to provide rapid and precise guidance in clinical therapies.
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Tianxun
authors: T
authors: Huang
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Yan
authors: Y
authors: Zheng
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Ya
authors: Y
authors: Yan
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Lingling
authors: L
authors: Yang
authors: Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Yihui
authors: Y
authors: Yao
authors: The First Affiliated Hospital of Xiamen University, Xiamen, Fujian 361005,P.R. China.
authors: Jiaxin
authors: J
authors: Zheng
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Lina
authors: L
authors: Wu
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Xu
authors: X
authors: Wang
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China.
authors: Yuqing
authors: Y
authors: Chen
authors: The First Affiliated Hospital of Xiamen University, Xiamen, Fujian 361005,P.R. China.
authors: Jinchun
authors: J
authors: Xing
authors: The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, P.R. China. Electronic address: xmyan@xmu.edu.cn.
authors: Xiaomei
authors: X
authors: Yan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology / Q000652:urine; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1
keywords: Antibiotic-resistant infection; Bacterial detection; Clinical diagnosis; Flow cytometry; β-lactamase resistance