Final answer:
Common methods for isolating and counting bacteria include spread plate, pour plate, membrane filtration, and streak plate methods. Serial dilution is also integral in preparing samples for these methods. Additional tests, like the disk-diffusion and use-dilution test, assess the effectiveness of antibacterial agents.
Step-by-step explanation:
The question pertains to methods commonly used for isolating bacteria and counting viable cells within a sample. The most frequently used methods include the spread plate method, where a sample is spread on agar using a sterile spreader; the pour plate method, involving serial dilutions of a culture; and the membrane filtration technique, used for very dilute samples like drinking water, where the sample is filtered and then cultured on appropriate media for cell count.
Another method to isolate bacteria is the streak plate method, which dilutes individual cells across an agar plate, allowing single cells to form colonies indicative of a pure culture. In serial dilution, a culture is diluted systematically to achieve a countable range of colony-forming units (CFUs), typically between 30-300. The membrane filtration technique helps in counting live cells in dilute solutions by filtering a sample through a membrane and culturing the retained microorganisms. Additionally, to measure the antibacterial effectiveness of chemical agents, the disk-diffusion and use-dilution test methods can be applied.