Question

You have isolated a bacterium in pure culture. Based on some morphological and biochemical tests you suspect this bacterium is of the species Klebsiella pneumoniae. In order to confirm this you utilize molecular techniques to assess the relatedness of your isolate to a type strain (a well-characterized version) of K. pneumoniae.

1. What two molecular methods would you use to compare your isolated bacterium to K. pneumoniae?
2. What criterion would you use with these two tests to confidently say your isolated bacteria is a member of the species K. pneumoniae?

Answer 1

Two molecular techniques that can be used for comparison and reasons are :

1.  16S rRNA gene sequencing- It remains the same during the course of evolution. Thus if the sequencing patterns of unknown bacteria show similarity with known bacteria we can confidently say they are closely related.

2. FISH (fluorescence in situ hybridization) technique can also be used by fluorescently tagging the DNA fragments of the unknown species with the known ones. The extent of binding can be recorded and can detect whether or not they are related .