Chemical susceptibility inspection method
The purpose of this invention is to provide an inspection method which enables us to judge a microbe's chemical susceptibility quickly, versatile and cheap. The inspection method of this invention's one aspect comprises a step for judging the chemical susceptibility to the antimicrobial of the microbe based on appearance-changing of the observed microbe. The step for judging may judge the chemical susceptibility by obtaining a feature of the plurality of images in the database regarding a plurality of images of microbes which have already been confirmed that they are resistant microbes and a plurality of images of microbes which have already been confirmed that they have susceptibility to an antimicrobial by machine learning and by comparing the images of the microbes with the images in the database based on the feature. Furthermore, the step for judging may judge the chemical susceptibility based on an abundance ratio of the microbe whose appearance changed out of the microbe in the field.
1 . An inspection method for inspecting susceptibility of a first microbe to an antimicrobial, comprising:
mixing the first microbe in a culture fluid with the antimicrobial at a predetermined concentration to prepare the antimicrobial sample;
keeping the antimicrobial sample and a control sample warm at a temperature above room temperature, the control sample comprising a culture fluid comprising a second microbe that is of a same strain as the first microbe, the control sample without the antimicrobial;
observing the antimicrobial sample comprising the first microbe at an initial time and at a plurality of time intervals by a microscope, and observing the control sample comprising the second microbe at at least one of the plurality of time intervals by the microscope, the initial time being a time zero at which the first microbe is not influenced by the antimicrobial;
counting a number of the first microbe in a field of the microscope at one of the plurality of time intervals after mixing the culture fluid containing the first microbe with the antimicrobial;
analyzing an appearance of an observed first microbe and comparing a first image regarding an appearance of the observed first microbe with a second image regarding an appearance of an observed second microbe at at least one of the plurality of time intervals;
discriminating microbes with a change in appearance since the initial time from the first microbe;
calculating an abundance ratio of a number of the microbes with a change in appearance compared to the number of the first microbe in the field, when the abundance ratio exceeds a predetermined value, the microbe is judged to have susceptibility to the antimicrobial, and the judging is confirmed twice consecutively; and
determining a minimum inhibitory concentration of the antimicrobial to the first microbe based on an appearance-changing of the observed first microbe, from the initial time to one of the plurality of time intervals, wherein the minimum inhibitory concentration is the lowest antimicrobial concentration among two antimicrobial samples that are judged to have susceptibility to the antimicrobial;
wherein the microscope is a scanning electron microscope or a scanning probe microscope;
wherein samples observed by the microscope consists of the antimicrobial sample and the control sample.
2 . The inspection method according to claim 1 , further comprising:
putting a plurality of images of drug-resistant microbes into a database;
putting a second plurality of images of microbes that are not drug-resistant into the database; and
obtaining a feature of the plurality of images and the second plurality of images in the database by machine learning, the feature comprising a ratio between microbes without refraction and microbes with refraction at the initial time, cell elongation, micronization, and spheronization; and
wherein the determining comprises comparing the first image and the second image with the plurality of images and the second plurality of images in the database based on the feature.
3 . The inspection method according to claim 1 , wherein the appearance of the observed first microbe or the observed second microbe is a shape of the observed first microbe or the observed second microbe, and/or a brightness of the region where the observed first microbe or the observed second microbe exists.
4 . The inspection method according to claim 3 , wherein the shape of the observed first microbe or the observed second microbe is a shape of a group in case that a plurality of the observed first microbes or a plurality of the observed second microbes form a group, and/or a shape of each observed first microbe or each observed second microbe that is independent of the group.
5 . The inspection method according to claim 1 , wherein the observing comprises observing a same antimicrobial sample in a plurality of fields by the microscope, and the calculating comprises determining the abundance ratio of the number of the microbes whose appearance changed based on a total number of the microbes in the plurality of fields.
6 . The inspection method according to claim 1 , wherein the determining is based on time-changing of the abundance ratio.
7 . The inspection method according to claim 1 , wherein the analyzing comprises obtaining an appearance information of a whole microbe constructed by gathering appearance data of an observed microbe, and the determining comprises comparing an appearance information for the antimicrobial that is administered to treat a microbe a human has to an appearance information for the antimicrobial that is not administered to the human, and determining the minimum inhibitory concentration based on the comparing.