One of the advantages of some newly developed rapid identifi

One of the advantages of some newly developed rapid identification tools is that pure cultures are not needed. Why is that pure cultures are not needed. Why is a pure culture necessary for biochemical tests such as Enteroutube, but not for DNA probes?

Solution

We generally perform biochemical tests to identify unknown microbes. Now, if we don’t have a pure culture and the culture contains other unwanted organisms, it could skew the results of the biochemical test. Sometimes it may also lead to false-positive or false-negative results of the test.

Therefore, by not having a pure culture, we will have inaccurate results.

For patient diagnostic tests, this could result in false negatives or false positive in biochemical tests, which could lead to giving a patient an incorrect treatment.

On the other hand, when newer tools such as DNA probes are used, they are very specific. DNA probes bind directly to target sites or nucleic acid sequences, which is very unique to that microbe. So even if we don’t have a pure culture, the probe will be able to bind to the DNA of the specific microbe only. Hence, a pure culture would be unnecessary.