Method of detecting bacteria in a fluid using forward-scatter technique
AssigneeBacterioScan LTD.
InventorAmnon Weichselbaum
Life of this patent
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Abstract
A method for detecting and counting particles suspended in fluids, such as bacteria suspended in urine, utilizing dynamic features of the suspended particles and employing light scattering measurements. The disclosed method is suitable for determining the susceptibility of bacteria to antibiotics. A cuvette for detecting bacteria in fluids, which is especially suited for the light scattering measurements, is provided.
Claims14
A method of detecting bacteria suspended in a biological fluid in a system having a light source for generating an input light beam that transmits along an input beam axis entering a cuvette to illuminate a portion of the biological fluid in the cuvette, the system further having a light detector for receiving light forwardly scattered from the biological fluid, the method comprising:
- filtering the biological fluid and placing the filtered biological fluid in the cuvette that holds the filtered biological fluid, the cuvette having a first window and an opposing second window that are transparent and made of a plastic material, the first window being located on the opposite side of the cuvette from the second window, each of the windows having an optical quality defined by a scratch/dig number that is 40/20 or lower;
- aligning the cuvette in the system such that the first window and the opposing second window are aligned with the input beam axis of the input light beam;
- regulating the temperature of the cuvette to affect the bacteria within the filtered biological fluid;
- illuminating a portion of the filtered biological fluid with the input light beam to create forward-scattered light exiting the second window in locations spaced apart from the input beam axis;
- obscuring a remaining portion of input light beam that exits the second window of the cuvette prior to the remaining portion of the input light beam encountering the light detector, the light detector being located behind the second window in the direction of the input beam axis and being spaced away from the second window in the direction of the input beam axis;
- repeatedly receiving forward-scattered signals at the light detector due to the forward-scattered light, the forward-scattered light being indicative of the bacteria within the fluid sample;
- and
- using the forward-scattered signals to determine a change in bacterial count over a period of time.
A method of detecting bacteria suspended in a biological fluid in a system having a light source for generating an input light beam entering a cuvette along an input beam axis to illuminate a portion of the biological fluid in the cuvette, the system further including a light detector for receiving light forwardly scattered from the biological fluid, the method comprising:
- filtering the biological fluid and placing the filtered biological fluid in the cuvette that holds the filtered biological fluid, the cuvette having first and second windows that are transparent and being made of a plastic material, the first window being located on the opposite side of the at least one cuvette from the second window;
- aligning the at least one cuvette in the system such that the first window and the second window are aligned with the input beam axis of the input light beam;
- regulating the temperature of the at least one cuvette to affect the bacteria within the filtered biological fluid;
- illuminating a portion of the filtered biological fluid with the input light beam to create forward-scattered light exiting the second window in locations spaced apart from the input beam axis;
- at a location behind the second window and in front of the light detector in the direction of the input beam axis, obscuring the remaining portion of the input light beam after the input light beam has exited the second window to inhibit an effect of the input light beam on the light detector;
- and
- repeatedly receiving forward-scattered signals at the light detector due to the forward-scattered light, the forward scatter signals being used to determine a change in a bacterial count in the biological fluid.
Dependencies are inferred from the claim text.