1. Mass Spectrometry-Based Escherichia coli H Antigen/Flagella Typing: Validation and Comparison with Traditional Serotyping.
- Author
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Cheng K, She YM, Chui H, Domish L, Sloan A, Hernandez D, McCorrister S, Ma J, Xu B, Reimer A, Knox JD, and Wang G
- Subjects
- Antigens, Bacterial immunology, Canada, Escherichia coli immunology, Escherichia coli isolation & purification, Flagella immunology, Sensitivity and Specificity, Antigens, Bacterial analysis, Antigens, Bacterial chemistry, Escherichia coli chemistry, Flagella chemistry, Mass Spectrometry methods, Serotyping methods, Serotyping standards
- Abstract
Background: Escherichia coli H antigen typing with antisera, a useful method for flagella clinical identification and classification, is a time-consuming process because of the need to induce flagella growth and the occurrence of undetermined strains. We developed an alternative rapid and analytically sensitive mass spectrometry (MS) method, termed MS-based H antigen typing (MS-H), and applied it at the protein sequence level for H antigen typing. We also performed a comparison with traditional serotyping on reference strains and clinical isolates., Methods: On the basis of international guidelines, the analytical selectivity and sensitivity, imprecision, correlation, repeatability, and reproducibility of the MS-H platform was evaluated using reference strains. Comparison of MS-H typing and serotyping was performed using 302 clinical isolates from 5 Canadian provinces, and discrepant results between the 2 platforms were resolved through whole genome sequencing., Results: Repeated tests on reference strain EDL933 demonstrated a lower limit of the measuring interval at the subsingle colony (16.97 μg or 1.465 × 10(7) cells) level and close correlation (r(2) > 0.99) between cell culture biomass and sequence coverage. The CV was <10.0% among multiple repeats with 4 reference strains. Intra- and interlaboratory tests demonstrated that the MS-H method was robust and reproducible under various sample preparation and instrumentation conditions. Using discrepancy analysis via whole genome sequencing, performed on isolates with discrepant results, MS-H accurately identified 12.3% more isolates than conventional serotyping., Conclusions: MS-H typing of E. coli is useful for fast and accurate flagella typing and could be very useful during E. coli outbreaks., (© 2016 American Association for Clinical Chemistry.)
- Published
- 2016
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