Cuvette for detecting bacteria and determining their susceptibility to antibiotics

A method of determining susceptibility of bacteria to different chemo-effecter agents by use of a system having a light source for generating an input light beam that transmits along an input beam axis and enters a cuvette containing a biological fluid having the bacteria, the system further having a light detector for receiving light forwardly scattered from the biological fluid, the method comprising:

• mixing the biological fluid having the bacteria with a first chemo-effecter agent in a first cuvette to form a first mixed fluid sample, the first cuvette having a first entry window and a first exit window that are transparent and made of a plastic material, the first exit window being located on the opposite side of the first cuvette from the first entry window;
• mixing the biological fluid having the bacteria with a second chemo-effecter agent in a second cuvette to form a second mixed fluid sample, the second cuvette having a second entry window and a second exit window that are transparent and made of a plastic material, the second exit window being located on the opposite side of the second cuvette from the second entry window;
• aligning the first cuvette in the system such that the first entry window and the first exit window are aligned with the input beam axis of the input light beam;
• illuminating a portion of the first mixed fluid sample within the first cuvette with the input light beam to create forward-scattered light exiting the first exit window in locations spaced apart from the input beam axis;
• at a location behind the first exit window and in front of the light detector in the direction of the input beam axis, obscuring a remaining portion of the input light beam that exits the first exit window of the first cuvette to inhibit an effect of the input light beam on the light detector;
• repeatedly receiving a first set of forward-scattered signals at the light detector due to the forward-scattered light from first mixed fluid sample;
• aligning the second cuvette in the system such that the second entry window and the second exit window are aligned with the input beam axis of the input light beam;
• illuminating a portion of the second mixed fluid sample within the second cuvette with the input light beam to create forward-scattered light exiting the second exit window in locations spaced apart from the input beam axis;
• at a location behind the second exit window and in front of the light detector in the direction of the input beam axis, obscuring a remaining portion of the input light beam that exits the second exit window of the second cuvette to inhibit an effect of the input light beam on the light detector;
• repeatedly receiving a second set of forward-scattered signals at the light detector due to the forward-scattered light from second mixed fluid sample;
• and
• comparing the first set of forward-scattered signals and the second set of forward-scattered signals to determine the susceptibility of the bacteria to the first chemo-effector agent and the second chemo-effector agent.