Scientists don't divide bacteria into two kingdoms. Instead, they classify bacteria into a single domain called Bacteria (also known as Eubacteria).

However, within the domain Bacteria, there are two main categories based on their gram staining results:

* Gram-positive bacteria: These bacteria have a thick peptidoglycan layer in their cell wall, which stains purple with Gram stain.

* Gram-negative bacteria: These bacteria have a thinner peptidoglycan layer and an outer membrane, which stains pink with Gram stain.

It's important to note that these categories are based on a staining technique and not a taxonomic classification. There are many other ways to classify bacteria, such as by their shape, metabolism, or genetic characteristics.