Kits for Escherichia coli and Shigella screening

Abstract

The invention provides a kit for discriminating escherichia coli and shigella, and relates to the technical field of pathogen discrimination and detection based on mass spectrometry. According to theinvention, a biochemical method and a mass spectrum technology are combined; according to the respective biochemical characteristics of escherichia coli and shigella, it is determined that the mass-to-charge ratios m / z of the two characteristic proteins are 103.12 + / -0.1 and 89.10 + / -0.1 respectively; a biochemical kit reaction solution is combined, and the two characteristic peaks are detected through MALDI-TOF MS, so that whether a to-be-detected sample is escherichia coli or shigella can be accurately judged, and meanwhile whether the to-be-detected sample is shigella sonnei or not is determined. The kit disclosed by the invention contains a biochemical reagent, a reaction solution and a standard correction solution, and the method is high in accuracy, good in repeatability, high in flux, low in detection cost and reliable in result and has a good application prospect.

Description

technical field [0001] The invention relates to the technical field of protein spectrum detection, in particular, to a kit for screening Escherichia coli and Shigella and identifying Shigella somnifera. Background technique [0002] Pathogenic Escherichia coli includes five types, namely enterohemorrhagic Escherichia coli (EHEC), pathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enteroinvasive Escherichia coli (EIEC) and coagulative Escherichia coli Escherichia coli (EAEC). According to different biochemical reactions and O antigens, Shigella is divided into 4 serogroups, namely Shigella dysentery (group A), Shigella flexneri (group B), Shigella baumannii (group C), and S. Shigella (group D). Escherichia coli and Shigella are closely related, and are genetically very close and have similar genetic information. Therefore, it is very difficult to distinguish Escherichia coli from Shigella and the four groups of Shigella, but it is of great signific...

AI Technical Summary

Problems solved by technology

However, there are two problems with this method. One is that this method is based on the ribosomal protein of Shigella sonnei itself, which is manually distinguished by conventional means of MALDI-TOF MS. The workload is cumbersome and complicated. TOF MS combined with the ClinProTools software method can completely screen and obtain the characteristic protein peaks of Shiga Songnai more efficiently, and replace this technology, and the coverage of ribosomal protein screening of Shigella Songnai is wider. Another problem is that the characteristic protein The peak is characterized by 5612.81±8.7, etc. This characterization method is incorrect in this field. For example, 5612.81 is the peak mass-to-charge ratio, and 8.7 is the signal-to-noise ratio. It is unreasonable to add and subtract two different unit values. And because the signal-to-noise ratio is not a fixed value, each spectrum is not exactly the same, and the mass-to-charge ratio (mass size) cannot be added or subtracted from the signal-to-noise ratio (the ratio of signal strength); these four proteins cannot be used to distinguish Song Shigella and Escherichia coli, not to mention the distinction between Shigella populations

[0004] For the identification of Escherichia coli and Shigella, and the identification of Shigella populations, traditional biochemical methods and serological methods are currently used, which are complicated, time-consuming, and costly

The identification results of Escherichia coli and Shigella based on MALDI-TOF MS are confusing, and the improved technical method published in the article can only achieve the highest discrimination ability of 94%; based on MALDI-TOF MS technology, it is impossible to identify Shigella populations. In particular, it is easy to mistakenly detect Shigella as Escherichia coli, which makes it impossible to accurately distinguish Escherichia coli from Shigella with MALDI-TOF MS technology, and it is impossible to further identify whether Shigella is Shigella sonnei. It brings inconvenience and risk of misdiagnosis to food safety inspection, identification of infectious disease pathogens and prevention and control of infectious diseases

[0005] Therefore, when an unknown bacterium is identified by MALDI-TOF mass spectrometry and the identification result is E. coli or Shigella or E. coli + Shigella, the current MALDI-TOF mass spectrometry method cannot further distinguish E. coli and Shigella, let alone To accurately identify whether it is Shigella sonnei, there is an urgent need for a high-throughput, accurate, and easy-to-operate type discrimination method for Escherichia coli and Shigella, as well as Chinese isolates of Shigella, in order to develop independent knowledge The mass spectrometry screening technology of property rights provides new technical support for the prevention and control of infectious diseases

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