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FIELD OF THE INVENTION

The present invention relates generally to the field of measurements of biological liquid samples. Specifically, the present invention relates to systems and method for determining whether bacteria are present in a liquid sample and, if so, for determining the effect of chemoeffectors on the bacteria within the liquid sample.

BACKGROUND OF THE INVENTION

Many applications in the field of analytical research and clinical testing utilize methods for analyzing liquid samples. Among those methods are optical measurements that measure absorbance, turbidity, fluorescence/luminescence, and optical scattering measurements. Optical laser scattering is one of the most sensitive methods, but its implementation can be very challenging, especially when analyzing biological samples in which suspended particles are relatively transparent in the medium.

One particle that often requires evaluation within a liquid is bacteria. The presence of bacteria is often checked with biological liquids, such as urine, amniotic, pleural, peritoneal and spinal liquids. In a common analytical method, culturing of the bacteria can be time-consuming and involves the use of bacterial-growth plates placed within incubators. Normally, laboratory results take may take a day or several days to determine whether the subject liquid is infected with bacteria and the type of bacteria.

Quantification of bacteria, yeast, and other organisms in fluid can be useful for medical diagnosis, drug development, industrial hygiene, food safety, and many other fields. Measurement of light scattering and absorption in samples is a known method for approximating the concentration of organisms. For example, techniques for detecting and counting bacteria are generally described in U.S. Pat. Nos. 7,961,311 and 8,339,601, both of which are commonly owned and are herein incorporated by reference in their entireties.

Accordingly, there is a need for an improved systems and methods that quickly determine whether bacteria is present in the fluid sample and determine the effect of chemoeffectors on a fluid sample. There is also a need for an improved systems and methods that more quickly determine the type of bacteria after the presence of bacteria is determined.

SUMMARY OF THE INVENTION

The present invention is directed to an instrument for taking measurements of organism concentration in multiple fluid samples or in a single fluid sample as a production tool for microbiology. The instrument may hold multiple, individually-loaded, independent fluid samples and determine bacteria concentration of each sample via a forward-scattering signal. Or the instrument may hold a single fluid sample in multiple wells, which contain one or more different chemoeffectors to act on the single fluid. Thus, the effects of a chemoeffector (or concentrations of chemoeffectors) on the bacteria concentration in each fluid sample can be based on forward-scattering signals of the fluid sample over a period of time.

In one aspect, the instrument determines a concentration of bacteria in a plurality of fluid samples, and comprises a housing, a rotatable platform, a plurality of fluid containers, a light source, a sensor, and a motor. The rotatable platform is within the housing. Each of the plurality of fluid containers is coupled to the rotatable platform. Each of the fluid containers holds a corresponding one of the plurality of fluid samples. Each of the fluid containers has an input window and an output window. The light source is within the housing and provides an input beam for transmission into the input windows of the fluid containers and through the corresponding fluid samples. The input beam creates a forward-scatter signal associated with the concentration of bacteria. The motor rotates the rotatable platform so that the input beam sequentially passes through each of the plurality of fluid samples. At least one sensor within the housing detects the forward-scatter signal exiting from the output window associated with the fluid sample receiving the input beam.

In yet a further aspect, the present invention is a method of determining the concentration of bacteria in a plurality of fluid samples. The method includes placing each of the fluid samples in a corresponding one of a plurality of fluid chambers located within a cuvette. Each fluid chamber has a first window for receiving an input beam and a second window for transmitting a forward-scatter signal caused by the input beam. The method further includes registering the cuvette on a rotatable platform associated with an optical measuring instrument, incrementally rotating the rotatable platform so as to sequentially pass the input beam through each of the fluid samples, and in response to passing the input beam through each of the fluid samples, measuring a first forward-scatter signal for each of the fluid samples.

Alternatively, the present invention is an optical measuring instrument for determining a concentration of bacteria in fluid samples. The instrument comprises a housing, a door, a light source, and a rotatable platform. The door is coupled to the housing. The door includes a door platform that extends inwardly into the housing when the door is positioned in a closed state. The light source and a sensor measure an optical signal from the fluid samples. The optical scatter signal is associated with the concentration of bacteria. The rotatable platform is coupled to the door platform. The rotatable platform receives one or more cuvettes that hold the fluid samples. The rotatable platform sequentially moves each of the fluid samples into a testing position for measurement by use of the light source and the sensor.

In yet another aspect, the present invention is an optical measuring instrument for determining a concentration of bacteria in a plurality of fluid samples. The instrument includes a cuvette, a first light source, a first sensor, a second light source, and a second sensor. The cuvette has a plurality of optical chambers for receiving a respective one of the plurality of fluid samples. Each of the optical chambers is at least partially formed by an entry window for allowing transmission of an input beam through the respective fluid sample and an exit window for transmitting an optical signal caused by the bacteria within the respective fluid sample. A first group of the optical chambers contains a first group of the fluid samples. A second group of the optical chambers contains a second group of the fluid samples. The first group of the optical chambers is located on a first locus having a first radius, and the second group of the optical chambers is located on a second locus having a second radius. The first radius is different from the second radius. The first light source produces a first input beam. The first sensor receives a first optical signal that is responsive to a bacterial concentration in the fluid sample and the first input beam. The first light source and the first sensor develop a first series of optical signals that are used for determining the concentration of bacteria within each fluid sample of the first group of fluid samples. The second light source produces a second input beam. The second sensor receives a second optical signal that is responsive to a bacterial concentration in the fluid sample and the second input beam. The second light source and the second sensor develop a second series of optical signals that are used for determining the concentration of bacteria within each fluid sample of the second group of fluid samples.

In another aspect, the present invention is a cuvette for use in an optical measuring instrument for determining a characteristic of a plurality of fluid samples. The cuvette includes a plurality of optical chambers for receiving a respective one of the plurality of fluid samples. Each of the optical chambers includes an entry window for allowing transmission of an input beam through the respective fluid sample and an exit window for transmitting an optical signal caused by the respective fluid sample. A first group of the optical chambers is located on a first locus having a first radius, while a second group of the optical chambers is located on a second locus having a second radius. The first radius being different from the second radius.

Additional aspects of the invention will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided below.

