Binomial Nomenclature: The correct format for the genus species or a species’ scientific name

The genus name always has the first letter capitalized and species name (and subspecies, if applicable) is in all small case. Strain names appear in normal font. When the name appears in normal font like this, the name is either in italics or underlined without an underline in the space between the names. Here are two examples: Klebsiella pneumoniae or Klebsiella pneumoniae. Underlining is more common when the name is written by hand and italics are frequently used when typed.

If the name appears in a sentence that is already italicized like this one, then the binomial name appears as normal text so that Klebsiella pneumoniae appears like this and the rest of the sentence continues in italics.

Here are some examples wrong ways of portraying the binomial name in a regular-font sentence: Klebsiella pneumoniae, klebsiella pneumoniae, Klebsiella Pneumoniae, Klebsiella pneumoniae, Klebsiella pneumoniae, and Klebsiella pneumoniae.” If the name is entered in a simple text field where font formats cannot be conveyed, then enter it like Klebsiella pneumoniae.

This is a good article on binomial nomenclature, https://en.wikipedia.org/wiki/Binomial_nomenclature, although they incorrectly portray “Homo sapiens” with an underlined space.