Device for testing bacterium, and method for testing bacterium

A bacteria test apparatus that identifies bacteria and conducts an antibacterial susceptibility test, the bacteria test apparatus comprising:

• a microscope optical system which captures for each of a plurality of wells holding a culture solution containing an antibacterial drug and the bacteria undergoing the antibacterial susceptibility test, a plurality of images of the well including the bacteria at a plurality of time points;
• a processor which calculates, for each of the plurality of wells, a feature of luminance value for each of the images, and determines, for the each of the plurality of wells, whether growth of the bacteria has occurred in the plurality of wells based on a temporal change in the feature of luminance value, wherein the processor calculates statistical features comprising mean luminance values from the images at preset times, calculates differences from mean luminance values at initial culture stage, and estimates growth curves based on corrected time variation in bacteria area with assumption of constant growth rate;
• and
• a display device which displays a determination result output based on the calculation and determination by the processor,
• wherein the calculation includes at least one of a mean, a median, or a mode of the luminance values of an entire image of the well, and
• whether the growth of the bacteria has occurred based on a combination of the mode of luminance values and an area of the bacteria, by correcting a time variation in the area of the bacteria based on a time variation in the feature of luminance value.