Summary
Classification of microbes using phenotypic traits, rRNA and whole-genome similarity.
In depth
Bergey's Manual and the Genome Taxonomy Database. Average nucleotide identity of 95 percent suggests the same species. Names are validated by publication.
Taxonomy now relies on genomic similarity (ANI, dDDH). Names must follow codes. Uncultured microbes receive provisional names.
Key idea: many microbes remain unnamed.
Classification has moved from phenotype (shape, Gram stain, biochemical tests) to genome-based taxonomy. A species is usually defined as strains sharing about 95 percent ANI or 70 percent DNA-DNA hybridisation, plus phenotype. The Genome Taxonomy Database (GTDB) reorganises classification by phylogeny. Uncultured taxa are named with Candidatus.
Names are written in italics with a capitalised genus and lower-case species (Escherichia coli, abbreviated E. coli), and strains may be given designations such as K-12. Nomenclature is governed by the International Code of Nomenclature of Prokaryotes. Horizontal gene transfer makes species boundaries blurry, and the tree is sometimes seen as a network.
Frequently asked questions
What is Microbial Taxonomy?
Classification of microbes using phenotypic traits, rRNA and whole-genome similarity.
Which area of biology covers Microbial Taxonomy, and how advanced is it?
Microbial Taxonomy is one of the 54 topics in Microbiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Bacterial Genetics, Gut-Brain Axis, 16S rRNA Sequencing.
Why does Microbial Taxonomy matter?
Correct identification is needed in diagnostics, outbreaks and regulations.
Can you give an example of Microbial Taxonomy?
Escherichia coli is named for Theodor Escherich.
What should I learn before Microbial Taxonomy?
Work through the Beginner topics in Microbiology first, such as Microorganisms, Bacteria, Archaea, then return to Microbial Taxonomy. Advanced topics assume the Intermediate vocabulary.
What topics are related to Microbial Taxonomy?
The closest topics to Microbial Taxonomy are Bacterial Genetics, Gut-Brain Axis, 16S rRNA Sequencing, Metagenomics. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Microbial Taxonomy?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Microbial Taxonomy. To practise the whole of Microbiology, use the Microbiology quiz.
How is Microbial Taxonomy different from Bacterial Genetics?
Microbial Taxonomy: Classification of microbes using phenotypic traits, rRNA and whole-genome similarity. Bacterial Genetics: Bacteria change genetically through mutation and by exchanging DNA by transformation, transduction and conjugation. Read both side by side and note what each one explains.
How should I study Microbial Taxonomy step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Bacterial Genetics and explain the difference aloud. Finally, take the Microbiology quiz and come back to this page for any question you miss.