Method for evaluating the virulence of pathogenic biphasic bacteria

A technology of bacterial toxicity and bacteria, which is applied in the field of virulence of pathogenic bacteria in two phases, can solve the problems of long incubation time and difficulty in accurately detecting pathogenic bacteria

Inactive Publication Date: 2011-06-22
GENERAL ELECTRIC CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, culture-based methods require lengthy incubation times and are prone to false results as field samples may interfere with the method
Likewise, it is difficult to accurately detect low levels of pathogenic bacteria with hybridization-based methods

Method used

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  • Method for evaluating the virulence of pathogenic biphasic bacteria
  • Method for evaluating the virulence of pathogenic biphasic bacteria
  • Method for evaluating the virulence of pathogenic biphasic bacteria

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] A reference curve for determining the virulence of Legionella pneumophila was drawn.

[0040] Take out 3-5 colonies of Legionella pneumophila (Legionellapneumophila) from the previously propagated medium plate, grow in liquid medium for 48-72 hours, add to 40 ml of freshly sterilized liquid medium to prepare a sample. The samples were shaken (175 rpm) at 36°C for 24 hours.

[0041] A sample of Legionella pneumophila was added to another freshly sterilized liquid medium at a volume ratio of 1:40 to prepare a reference sample. The samples were shaken (175 rpm) at 36°C for 24 hours.

[0042] The reference samples were assayed at the following different time points to determine the various growth phases and DNA and RNA concentrations of Legionella pneumophila: 1.5 hours (for the lag phase), 6 hours, 9 hours (for the exponential phase), 26 hours Hours, 28 hours, 30 hours, 32 hours, 34 hours, 48 ​​hours, 51.5 hours, 73.5 hours and 77 hours (for the post-exponential period)....

Embodiment 2

[0053] Planktonic Legionella pneumophila cells were obtained from different 50 ml samples of cooling tower water by filtration-based concentration. Samples were filtered through a polyethersulfone (PES) 0.45 μm membrane. Cells were lysed on the membrane overnight with 3 ml chemical lysis buffer STM and the lysate was filtered through a PES 0.22 μm membrane to remove cell debris.

[0054] The DNA and rRNA in the lysate were quantitatively determined according to the method described in Example 1.

[0055] As shown in Table 1, most of these field samples had rRNA / DNA ratios in the range of 300-9000, indicating that the growth phase of Legionella pneumophila is post-exponential.

[0056] Table 1

[0057] sample

[0058] Samples 5, 9 and 14 had high RNA concentrations, indicating that they were in a less virulent exponential growth phase, which may be the result of the host shedding the bacteria for the first time.

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PUM

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Abstract

A method for evaluating relative bacterial virulence of a biphasic bacteria in environmental systems includes measuring the concentration of DNA in the bacteria, measuring the concentration of RNA in the bacteria, determining a ratio of the concentration of RNA to the concentration of DNA and correlating the concentration ratio with a level of relative pathogenicity, wherein the bacteria is preferentially Legionella pneumophila, Mycobacterium tuberculosis and Listeria.

Description

field of invention [0001] The present invention relates to methods for assaying biphasic bacteria in environmental systems, and more specifically to methods for evaluating the virulence of biphasic bacteria in environmental systems. Background of the invention [0002] The presence of pathogenic bacteria in environmental or clinical samples from the water, food, healthcare or pharmaceutical industries can pose serious health concerns. Evaluating pathogenic bacteria to determine their virulence is critical to assessing the relative risk of these samples. Concentrations of microbial pathogens can be determined using conventional assays, such as culture-based or hybridization-based methods. However, culture-based methods require lengthy incubation times and are prone to erroneous results because field samples may interfere with the method. Likewise, it is difficult to accurately detect low levels of pathogenic bacteria with hybridization-based methods. More importantly, the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12Q1/68
CPCC12Q1/689Y02A50/30C12Q2561/113
Inventor S·M·博伊特陈静李洁徐韡卿K·杨
Owner GENERAL ELECTRIC CO
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