| The multi-channel series piezoelectric quartz crystal sensor (MSPQC) is designed based on the principle of series piezoelectric quartz crystal (SPQC). It has the ability of detection multi-samples at one time. It has many advantages, such as high sensitivity, easy operation, broad sensing spectrum, real-time and on-line measurement etc. It has been widely used in many areas, such as analytical chemistry, life science, environmental monitoring and clinical medicine etc. Based on the special response of MSPQC and several metabolism characteristics of the most commonly encountered bacteria in clinic, some new detection methods were presented in this thesis. These new methods had broadened their application in clinical medicine. These new methods for the detection and identification of the most frequent bacteria encountered in clinic were ease to operate,rapid and accurate. The main work could be summarized as follows:1. A new method for the rapid detection and simultaneous classification of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae based on combination of a multi-channel series piezoelectric quartz crystal sensor (MSPQC) with partial least squares (PLS) method was presented. With the proposed PLS-MSPQC system,47 clinical isolates were successfully identified from the simulating blood samples. According to the statistic analysis result, there was no significance discrepancy between PLS-MSPQC method and API 20C AUX method for identification of the four bacterial species (P>>0.05). All the results showed that the method proposed in this thesis had a potential capacity for identifying bacterial species directly without pure culture process, which was cost-cutting and time-saving.2. A model for the result judgment of MSPQC in clinical blood culture was constructed by using PLS method in thesis. In this paper,36 positive samples and 33 negative samples were used to construct the model. And the discrepancy of responsive curve between the bacteria sample and fungi sample was sufficiently considered during the modeling. The model constructed in this thesis not only had the ability to recognize the result (positive or negative) of clinical blood culture by MSPQC, but also could give the result that the type of the positive sample belongs to fungi or bacteria. The model was successfully used to judge 668 clinical samples, the negative and the positive accuracy were 90.74%,92.3% respectively, and the identification accuracy of fungi and bacteria in positive samples were 86.61%,97.14% respectively.3. An improved YC medium was proposed for rapid detection of Stenotrophomonas maltophilia by MSPQC in thesis. YC medium was improved by substituting maltose (10 g/1) for glucose (10 g/1) and methionine (0.5 g/1) was added as the role organic growth gene in it. The detection time of low concentration of Stenotrophomonas maltophilia in the modified YC medium by MSPQC was shortened by 3 h. And the detection limit was low to 10 cfu/ml. This research is meaningful for treating patients in time and decreasing the death rate.
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