Patent CA-1264434-A (CA)
Inventor: HORVATH JUDITH
IPC: C12M1/18
Filed: 1988-12-20
Granted: 1990-01-16
Abstract: ABSTRACT   It is known that some bacterial fermentations of sugars are associated with acid and gas productions. The production of gas then can be used as a diagnos-tic tool to identify the particular family of microorganisms present in the fermentation media. This type of diagnostic identification of families of mic-roorganisms are routinely carried out in health and water pollution laboratoriesby physically trapping the gas produced by the resident microorganisms in a water sample and media mix. The test is commonly used when laboratories are testing for the presence or absence of total and fecal coliform bacteria in a water sample to check the sanitary quality of water.   At the present, bacterial gas production is tested by trapping the gas produced by the use of an inverted vial ( Durham tube ) immersed and filled with liquid fermentation media. The extensive preparation of the fermentation tube is accomplished by placing the inner vial with the open end facing downwardinto a large fermentation tube containing the fermentation broth. This is fol-lowed by high temperature ( 121 C ) and pressure ( 15 lbs/square inch ) steri-lization for 15 min., followed by a very gradual cooling off period. The steri-lization procedure kills all microorganisms present in the media, and will also cause the escape of all air bubbles trapped inside the inner vial. When the testwater containing fermenting bacteria is added to the media, some of the gas produced will be physically trapped inside the inner fermentation vial in form of gas bubbles and will be visible to the examiner.   Alternatively, other kits are designed such way that the escape of trapped air bubbles is accomplished by inverting of the tightly capped fermentation tube containing sample and sterile media and the partially immersed inner vial a few times to mix until the inner tube is full of liquid. The tubes are then kept upright for the duration of the procedure. The gas produced will be trappedinside the inner Durham tube in form of visible gas bubbles. This procedure alsohas several limitations, it is designed to test for undiluted sample only.   This invention eliminates the necessity of high teperature and pressure sterilization and the lengthy cooling off period in order to produce a media filled and air bubble free inner fermentation vial ready for testing. A specially designed inner fermentation vial kit is utilized which can either be placed in-side the larger fermentation tube or be constructed to be permanently attached to the outside of the large fermentation bottle. The inner fermentation vial kitis equipped with an upper and lower reservoir separated by a constricted neck area and is open at both ends. The upper reservoir is equpped with an inner sliding cone-shaped plug that is operated by an extension rod attached to the cap of the upper reservoir. By depressing on the extension rod, the plug will produce a seal at the constricted neck area of the inner vial.   The closure of the neck area by the plug is carried out after the addition of the fermentation media into the fermentation vessel and the inner vial kit the point of media overflow well into the upper reservoir of the inner vial. The closure by the plug will then produce a media filled and air bubble free lower reservoir. Upon inoculating this system with test water containing fermenting bacteria, a portion of the gas produced will be trapped inside the lower reser-voir of the inner vial kit in form of gas bubbles below the plug, allowing for visual examination while the uncontaminated media in the upper reservoir will act as a quality control check against seal leakage.     This fermentation system allows for the testing to be carried out in the field or in the laboratory without any prior, labour intensive high tempera-ture and pressure sterilization to produce a media filled and air bubble free inner vial for testing. The test can be carried out rapidly by the use of pre-packed and factory sterilized glassware and media.