Tag: most probable number
When Angelo Falcon chose his water source for the first project in BIOL 3410 Microbiology lab, he had little idea that it would bring to light an issue being discussed in Abilene City Hall. The class was charged with finding various sources of ground water and surface water to test for the numbers and types of bacteria present. Angelo sampled water from a man-made waterfall downtown, while others in the class tested streams and lakes and ponds and wells in and around Abilene. Testing included a standard MPN (most probable number) assay, followed by isolation and purification of a Gram negative bacterium, characterization of its colony morphology and staining characteristics, and biochemical testing to provide hints at its identity. The project culminated in confirming the identifications of isolates using BD-BBL Crystal(R) E/NF panels for rapid identification of enteric and non-fermenting Gram negative rods. Angelo’s isolate came back as Enterobacter cloacae, and a little snooping revealed this to be a microbe frequently associated with sewage and soil. A conversation with people associated with the waterfall revealed the water source to be a shallow well tapping into an aquifer found under much of northern Abilene.
And that is things began to add up. In early September, Abilene’s City Council dealt with the issue of shallow ground water in northern Abilene and its unsanitary condition by issuing a warning to residents with wells into this water source – do not drink the water, do not use the water for irrigating vegetables, do not allow pets or livestock to drink the water. Angelo can testify to the presence of nasty bacteria in the water. Add to Angelo’s work confirming evidence from Amanda Carter, a classmate who tested water from her father’s north-side well, and you have every reason to believe City Council made the right decision.
Its nice when what you are doing in the lab to develop basic skills has a purpose and relevance to society.