Abstract: Improved cards for use in an automated machine to detect the presence of specific microbes and thereby identify them, enumerate them, and/or determine their susceptibility to antibiotics. Each card includes a plate having conical detection wells each with a selected medium therein, at least one filling port with a septum which is retained by a collar formed therein, and filler passages of specific length and configuration connecting the port to the wells. Discontinuities are provided in the filler passages to prevent unwanted fluid flow and to reduce migration of the microbes when the card is in use. Overflow chambers of a specific configuration are also provided adjacent the wells to entrap bubbles.

Abstract: The concentration of microorganisms in a known volume of a water specimen is ascertained by introducing the water specimen into a plurality of wells which have known volume and contain a nutrient medium. The mixture of water specimen and nutrient medium is incubated and the wells are observed for a change in the appearance thereof which indicates metabolic activity, that is, the existence of microorganisms in the wells. If all the wells change appearance, then it is known that the concentration exceeds a certain limit, that is, at least one cell per specific well volume. On the other hand, if none of the wells change, then it is most likely the concentration is less than one cell per total volume of specimen in the wells. A change in appearance of some but not all of the wells indicates a concentration between the foregoing limits, and this concentration is estimated by statistical evaluation based on proven statistical computations.

Abstract: A process for determining the susceptibility of microorganisms to antibiotics involves introducing a diluted specimen into discrete quantities of a selective culture medium which favors a specific microorganism in that the microorganism is sustained by the medium and when so sustained will change the optical characteristics of the medium. Only the specific microorganism will alter the optical characteristics. Some of the discrete quantities are blended with known antibiotics, while at least one is not. If the specimen contains the microorganisms favored by the selective medium, the optical characteristics of the discrete quantity of pure selective medium, that is the one without antibiotics, will change. If the antibiotics in any of the other discrete quantities are ineffective against the favored microorganisms, the optical characteristics of those quantities will likewise change.