The Determination of the Presence of Coliform Bacteria from Selected Sources by Means of the Most Probable Number MPN Method
Coliform bacteria are good indicator organisms for the presence of pathogenic bacteria due to their realtionship with these pathogenic bacteria, their relative ease of determination by simple methods, and by their occurrence in large quantities in human feces. The MPN method used in this experiment is one of the prescribed techniques for the determination of these coliform bacteria from the Standard Methods for the Examination of Water and Wastewater as prescribed by the EPA. It consists of three stages, each of which necessitates a positive result for the previous stage. The first stage (presumptive test) determines the gas-producing coliform characteristic during lactose-fermentation. The second stage (confirmed test), determines the gram-reaction and also the lactose fermentation abilities of the organism, while the last stage (completed test) determines the endospore presence to determine if the organisms in the sample indeed are coliforms. The number of coliforms or bacteria present is readily seen with the use of a special table and then the statistically estimated numbers are determined. The samples, however, did not produce positive results for the presence of coliforms. Enventhough there was a large
These were then incubated for 48 hrs at 37ºC. If we compare this to the number of bacteria present, we would now have a notion of the relative amount of bacteria that are not coliform living on the sample. Better and more specific tests should thus be made by future researchers to make more accurate and definitive conclusions on the presence of coliforms in bodies of water. jp_~infortec_hotspots_boracay_infopol. Two each of pre-poured EMB and MacConkey agar plates were then inoculated, using streak plating technique for isolation, with samples from the test tube chosen. Safranin was then dropped on the slide, and after a minute, the slide was rinsed with tap water. The presence of 1100 MPN non-coliform bacteria per 100ml should not be taken as a health hazard. cultures of the organisms in the NA slant enumerated earlier that were fixed on a slide (like the smears on Gram staining). This narrows it down to a few groups of bacteria that ferment lactose. In this test the bacteria left are screened using again, lactose broths, for the final assurance of gas-production in lactose fermentation, gram staining, also for final assurance that the bacteria that passed are really gram-negative, and endospore staining, which will separate the non-coliforms from the coliforms. Discussion The tests made were done by stages in order to narrow down the possibilities in the determination of the presence of these coliform bacteria. These principles and procedures now form the basis and the rationale for the methods by which this experiment was conducted.
Common topics in this essay:
EMB MacConkey,
Lower Upper,
Introduction Human,
Gram Staining,
Presumptive Test,
Frank MPN,
Enterobacter NCSU,
Endospore Staining,
Washington DC,
Water Wastewater,
coliform bacteria,
test tubes,
confirmed test,
macconkey agar,
tap water,
indicator organisms,
1 0,
lactose fermentation,
tubes gas,
durham tubes,
2 oct 1999,
macconkey agar plates,
colonies macconkey agar,
inside durham tubes,
presence coliform bacteria,
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