Staphylococcus aureus and streptococcus salivarius bacteria have a thick pg layer and do not have an outer membrane. what color should a smear of either s. aureus or s. salivarius appear following gram staining?

Purple

Explanation:

The cell wall of gram-positive bacteria has a thick peptidoglycan layer present outside the plasma membrane. The gram-negative bacteria have a thin peptidoglycan layer covered by a thicker outer membrane. The outer membrane is absent in gram-positive bacteria.  

Given that Staphylococcus aureus and Streptococcus salivarius have a thick peptidoglycan layer and lack the outer membrane, they are gram-positive bacteria.

Due to the presence of a thick peptidoglycan layer, these gram-positive bacteria retain the purple color of crystal violet even after washing with ethanol or acetone.  

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