Method for determining sensitivity of bacteriophage to antibiotics

Abstract

The invention relates to the technical field of biological detection, and in particular relates to a method for evaluating the sensitivity of bacteriophage to antibiotics. According to the evaluation method of the invention, the relationship between the bacterial liquid OD600 and the bacterial quantity, the bacterial liquid dosage and the bacteriophage titer is established, it can be guaranteed that the bacterial liquid dosage meets the determination of the bacteriophage titer, the evaluation result is stable and high in reliability, and the evaluation method can be used for guiding a farmer to select proper bacteriophages and antibiotics with proper concentration for combination for scientific breeding. Therefore, the growth of pathogenic bacteria in the breeding process is effectively inhibited, the labor cost is greatly reduced, and the economic benefit is remarkably improved.

Description

technical field [0001] The invention relates to the technical field of biological analysis and detection, in particular to a method for determining the sensitivity of phages to antibiotics. Background technique [0002] The use of antibiotics to treat bacterial diseases is recognized as an effective way; however, long-term use of antibiotics will break the balance of intestinal flora, destroy the intestinal barrier, and then affect the immunity of animals, making it difficult to control the disease. In 2015, Professor Liu Jianhua of Huazhong Agricultural University and Professor Shen Jianzhong of China Agricultural University jointly published an article on the resistance of Myxobacter sulfate, which proved that the drug resistance of human pathogenic bacteria is related to the use of growth-promoting antibiotics in animals. Drug-resistant bacteria can be passed from animals to humans through the food chain, and more than 20,000 people die from superbugs every year. Therefor...

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Problems solved by technology

For example, Xiao Xi et al. (2017) used the double-layer plate method to detect the titer of bacteriophage JDOO7, but it could not guarantee that the Staphylococcus aureus solution was evenly coated on the surface of the plate, which would cause counting errors; Zhong Wenshi et al. When measuring the titer, the amount of bacterial solution is only 100 μL when laying double-layer plates, and the concentration of bacterial solution varies from batch to batch. If the volume of bacterial solution is used in quantitative experiments, it will cause large errors between repeated experiments.

The double-layer plate method has the following disadvantages: First, the phage activity is easily affected

When preparing a double-layer plate, mix the phage and the bacterial solution and add it to a semi-solid medium at 55°C to make it solidify. It will lead to agglomeration of the medium, uneven distribution of bacteria and phages; second, the amount of bacterial solution is not uniform; most experiments will directly add a certain amount of bacterial solution, such as 100 μL, but the repeatability of this operation is poor; there are also MOI The ratio is the reference for adding liquid, but the MOI values ​​of bacteria and phages must be detected in each experiment, the experiment period is long and the operation is complicated; third, the amount of phages is unreasonable; in addition to the problems mentioned in the second point, most of the phages also need to be tested. Performing a dilution gradient, if the gradient setting is unreasonable, it will cause the following two situations: more plaques, which cannot be counted together; or less plaques, and the counting difference is large

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