Device and method for the detection and enumeration of multiple groups of microorganisms

A method for monitoring the growth of primary and secondary groups of microorganisms simultaneously growing in a single test sample, comprising the steps of:

• introducing a mixture of materials into a container, the mixture of materials including a test sample, growth media compounded to promote growth of both the primary and secondary groups of microorganisms potentially present in the test sample, a chromogenic substrate material capable of selectively indicating growth of the primary groups of microorganisms, and a fluorogenic substrate material capable of selectively indicating growth of the secondary group of microorganisms, the container configured to receive the mixture of materials, the container made of material transparent to visible light and ultraviolet light in a specific spectral band, wherein said chromogenic and fluorogenic substrates are selected to enable the fluorogenic substrate to indicate the growth of the secondary group of microorganisms while the primary group of microorganisms is simultaneously growing and changing the color of said chromogenic substrate;
• introducing the container containing the introduced mixture of materials into a monitoring device, the monitoring device including;
• A) a photo reader associated with the container, the photo reader consisting of:
• 1) a visible light source generating electromagnetic energy directed through said transparent material of the container, the visible light source interacting with said chromogenic substrate to yield chromogenic interaction light indicative of growth of the primary groups of microorganisms;
• 2) an ultraviolet light source generating electromagnetic energy directed through said transparent material and interacting with said fluorogenic substrate to yield fluorogenic interaction light indicative of growth of the secondary groups of microorganisms;
• and
• 3) a single photo detector, capable of detecting said chromogenic interaction light and fluorogenic interaction light and producing detection signals respective to said chromogenic interaction light and said fluorogenic interaction light;
• and
• B) a controller electronically connected to the visible light source, the chromogenic light source and the single photo detector, the controller configured to switch the respective light sources on and off;
• switching on the visible light source associated with the photo reader and measuring the intensity of the chromogenic interaction light with the single photo detector;
• switching off the visible light, switching on the ultraviolet light source associated with the photo reader, and measuring the intensity of the fluorogenic interaction light with the single photo detector;
• and
• determining the presence of the primary and secondary groups of microorganisms by the intensities of the chromogenic interaction light and the fluorogenic interaction light, respectively.

A method for monitoring the growth of primary and secondary groups of microorganisms simultaneously growing in a single test sample, comprising the steps of:

• introducing a mixture of materials into a container, the mixture of materials including a test sample, growth media compounded to promote growth of both the primary and secondary groups of microorganisms potentially present in the test sample, a chromogenic substrate material capable of selectively indicating growth of the primary groups of microorganisms, and a fluorogenic substrate material capable of selectively indicating growth of the secondary group of microorganisms, the container configured to receive the mixture of materials, the container made of material transparent to visible light and ultraviolet light in a specific spectral band, wherein said chromogenic and fluorogenic substrates are selected to enable the fluorogenic substrate to indicate the growth of the secondary group of microorganisms while the primary group of microorganisms is simultaneously growing and changing the color of said chromogenic substrate;
• introducing the container containing the introduced mixture of materials into a monitoring device, the monitoring device including;
• A) a photo reader associated with the container, the photo reader consisting of:
• 1) a visible light source generating electromagnetic energy directed through said transparent material of the container, the visible light source interacting with said chromogenic substrate to yield chromogenic interaction light indicative of growth of the primary groups of microorganisms;
• 2) an ultraviolet light source generating electromagnetic energy directed through said transparent material and interacting with said fluorogenic substrate to yield fluorogenic interaction light indicative of growth of the secondary groups of microorganisms;
• and
• 3) a single photo detector, capable of detecting said chromogenic interaction light and fluorogenic interaction light and producing detection signals respective to said chromogenic interaction light and said fluorogenic interaction light;
• and
• B) a controller electronically connected to the visible light source, the chromogenic light source and the single photo detector, the controller configured to switch the respective light sources on and off;
• switching on the visible light source associated with the photo detector and measuring the intensity of the chromogenic interaction light with the single photo detector;
• switching off the visible light source associated with the photo detector, switching on the ultraviolet light source associated with the photo detector;
• measuring the intensity of the fluorogenic interaction light with the single photo detector;
• switching off the ultraviolet light source associated with the photo detector;
• and
• repeating the preceding steps at predetermined intervals to obtain a recorded time sequence of the chromogenic interaction light and a recorded time sequence of the fluorogenic interaction light for the container.