I'm lost...where do we belong?


There is no need to feel trapped when learning about taxonomy.  Below is a brief overview of some of the basic traits that you would expect to find in the various levels. 


Classification Information (User Created)



Bacteria: The three domains of life include Bacteria, Eukarya, and Archaea.  Salmonella enteritidis belongs in the Bacteria domain as it is prokaryotic, lacks a true nucleus, lacks membrane bound organelles, and contains peptidoglycan in the cell walls.


Eubacteria: Also known as “true bacteria,” the kingdom of Eubacteria is the most common kind of bacteria found today.  Most of the living bacteria that are known to be parasitic and cause diseases are also found in this kingdom.  The three basic morphological types of bacteria are: bacillus (rod shaped), cocci (spherical), and curved/helical.  Salmonella enteritidis is a bacillus shaped bacteria.

Proteobacteria: Although there is no known molecular characteristic that is unique within this phylum, rRNA sequencing similarities have placed Salmonella into this phylum.  Proteobacteria are gram-negative bacteria that appear pink under a microscope after being treated with Gram stain.  This means that the peptidoglycan component of the cell wall, which is located between the outer membrane and the plasma membrane, is thinner than the gram positive bacteria. Gram positive bacteria have a thicker layer of peptidoglycan and lack the outer membrane that is observed in gram-negative bacteria.

Gamma proteobacteria: This is the largest and most diverse class of the phylum, Proteobacteria.  This group consists of facilitative anaerobes which means that these bacteria can survive with or without oxygen. This broadens the environments that they can be found in.

Enterobacteriales: Many of these bacteria, "gram-negative enteric bacteria," can be found residing in the intestines of animals and humans.  Many important pathogens, such as Salmonella, are also included in this family.

Enterobacteriaceae: Members of this family are typically motile via flagella and also reduce nitrates.

Salmonella: These bacteria are chemoorganotrophic which means that they have both a respiratory and fermentative type of metabolism.  Salmonella also can occur in the environment, humans, and animals.


Time to see a phylogenetic tree that includes Salmonella enteritidis.