The light scattering of a number of aliquots of a given bacterial/broth suspension, each containing a different antibiotic are rapidly measured and compared with the forward light scattering of a control suspension of the bacteria in the absence of antibiotic. The inhibitory effectiveness of each antibiotic on the growth of the bacteria is then computed from the substantially simultaneous readings and printed out. The bacterial/broth suspension samples are conveniently deposited in a disposable, plastic, transparent, compartmented container or cuvette into which antibiotic discs are introduced into all but one compartment (chamber) from a ganged disc dispenser. After a brief agitated incubation period of about three hours, the covette is inserted in a photometric analyzer which measures the intensity of light scattered at some angle to the incident beam by each sample chamber and compares it with the light scattered at the same angle by the control chamber to which no antibiotic has been added. The relative effectiveness of each antibiotic is computed and recorded to determine which of the antibiotics is most suitable for treating the patient. The partitioned cuvette includes a filling reservoir from which the inoculated broth is introduced as equal volume aliquots into the interconnected lobes of a row of double lobed chambers. Rotation of the partitioned cuvette transfers the equal volumes of broth inoculum from the interconnected lobes to the transparent and separated lobes of the chambers. Then different antibiotic discs are simultaneously dropped within apertured tubes which are located within all chambers except the control chamber. Elution of the antibiotics into the liquid samples begins immediately. The cuvette is then placed in an incubator/shaker for approximately 3 hours at approximately 36.degree.C to promote bacterial growth and antibiotic elution. The light scattering readings are obtained at the end of the agitation/incubation period and the relative antibiotic effectiveness computed in an analyzer into which the cuvette is inserted and indexed past a light source. The light passes through a lens system which directs a beam of light successively through the transparent lobes of the cuvette. The readings are obtained at a predetermined angle of scatter of, for example, 35.degree.. Initial analog signals are converted to binary digits and logarithms to simplify normalization of the antibiotic-mediated inhibition of bacterial growth by the total growth in the control chamber. The normalized growth inhibition values are printed out and rated on a scale of 0 (no inhibition, total resistance) to 100 (complete inhibition, total susceptibility). In addition the total growth, which has occurred in the control chamber during the agitation/incubation period, is printed out as a logarithmic difference (growth index). If insufficient growth has occurred in the control chamber (growth index less than 0.9), the cuvette may be reincubated and reread before disposal.
The apparatus comprises a plurality of stationary cuvettes, a chamber for the fluid to be evaluated, means for placing the chamber in fluid communication with each of the cuvettes and for permitting the flow of fluid from the chamber into each of the cuvettes, a plurality of optical transmitting means in registration with each of the cuvettes for transmitting a beam of radiant energy through each of the cuvettes, and detector means for intercepting each of the beams of radiant energy and for measuring any optical changes in the radiant energy passing through the fluid in each of the cuvettes. The chamber for the fluid, the plurality of cuvettes and the fluid communication means are all housed within, preferably, a disposable, self-contained cartridge of unitary construction. The cartridge is mountable within a carriage that houses the transmitting and detector means of the apparatus. The chamber which forms the upper portion of the cartridge can be prefilled with bacterial suspension. Periodically, during the growth of the subject bacteria the suspensions are agitated by suitable means. Samples of antibiotics of varying potency are placed in the cuvettes. The cartridge is mounted in the carriage. On a signal from the detector means a portion of the suspension passes into each of the cuvettes to begin the antibiotic titer which is evaluated by means of the transmitting and detector means and associated electronic circuitry.
An apparatus for testing a substance is characterized by a substantially planar base member carrying a reservoir extending lengthwise thereon. A plurality of test zones, each having a chemical substance therein, are carried by the base and are disposed in a side-by-side relationship with each other and in a substantially perpendicular relationship with the reservoir. Each test zone is separated and isolated from the next adjacent test zone by a sidewall of a predetermined height. The test zones are each separated from the reservoir by a barrier having a height less than the height of the sidewall. A clear plastic cover is provided to enclose the reservoir and the test zones so that fluid communication is permitted only between each individual test zone and the reservoir through a clearance space defined between the interior of the cover and the top of the barrier. After introduction of the substance to be tested within the reservoir, the method comprises rotating the testing apparatus a predetermined angular distance about an axis of rotation extending longitudinally through the reservoir to permit the substance to be tested into enter each of the test zones through the defined clearance. The testing apparatus may be rotated in an angular direction opposite to the first angular direction to thereby return the apparatus to its original position and isolate the substance to be tested in each individual test zone.
A process for bacteria identification and for determining the sensitivity of bacteria to antibiotics, and an apparatus and measuring supports for carrying out this process. There is manually introduced, by means of a sampling and transfer tool, a given volume of bacterial colony into a primary receiver. This is automatically dispersed within a liquid to form a precalibrated inoculum in the primary receiver. There is automatically carried out total or partial transfer of this precalibrated inoculum between the primary receiver and one or more measuring supports, these transfers being carried out without the precalibrated inoculum being placed in contact with an element other than a sampling and transfer tool and/or the primary receiver and its final measuring support or supports and in such a way that the transferred quantities of bacteria correspond to the quantities required for the analyses to be carried out. The precalibrated inoculum is automatically distributed, optionally after having appropriately diluted it to end up with a definitive calibration in one or more compartments of the measuring supports containing mainly appropriate reagents. Measurements are taken on the content of the compartments during or at the end of one or more incubations undergone by the inoculum in the measuring supports, the measurements taken being registered by a computer and being processed in order to characterized the growth of the bacteria present in the inoculum, to identify them and/or to determine their sensitivity to various antibiotics.
A microprocessor based apparatus and method for recording antimicrobic susceptibility data and biotype data. Manual data entry means in the form of two separate arrays of switches are provided for entering susceptibility data from microdilution test panels and a biochemical identification panels. An LED array is provided in a test panel housing on the front panel of the instrument cabinet in which the system is housed for feedback of data entry under microprocessor control. A microprocessor system records the entered well coordinated data for the microdilution test panel wells and the biochemical identification panel wells and converts the entered data into a printout of the minimum inhibitory concentration (MIC) of antimicrobics in the MIC test panel and a probable identification of the unknown microorganism. A multicopy form is provided for the printout from a printer functioning under microprocessor control. The printout includes both human readable MIC and biochemical identification information and a machine readable code for subsequent entry of the information into a data base.
The present invention relates to processes for the preparation of new imidazoles, especially of 4- or 5-nitro-imidazoles, substituted by tetrahydroimidazoles which may be substituted and to such compounds which are valuable chemotherapeutica in the treatment of gram-negativ bacteria, protozoa and worms.
